1 00:00:00,000 --> 00:00:04,162 WWW.MY-SUBS.CO 1 00:00:03,888 --> 00:00:07,324 >> Earth, a unique planet, 2 00:00:07,358 --> 00:00:10,627 restless and dynamic. 3 00:00:10,728 --> 00:00:13,897 Continents shift and clash. 4 00:00:13,998 --> 00:00:17,534 volcanoes erupt. Glaciers grow 5 00:00:17,602 --> 00:00:19,236 and recede. 6 00:00:19,270 --> 00:00:20,504 Titanic forces that are 7 00:00:20,538 --> 00:00:23,073 constantly at work, leaving a 8 00:00:23,174 --> 00:00:25,142 trail of geological mysteries 9 00:00:25,176 --> 00:00:28,945 behind. 10 00:00:28,980 --> 00:00:30,414 In this episode, we investigate 11 00:00:30,481 --> 00:00:33,183 the formation of The Rockies, 12 00:00:33,217 --> 00:00:34,217 A North American mountain 13 00:00:34,318 --> 00:00:36,853 range shrouded in mystery, 14 00:00:36,954 --> 00:00:39,089 flanked by huge slabs of rocks 15 00:00:39,123 --> 00:00:40,957 with ancient sea fossils buried 16 00:00:41,025 --> 00:00:43,026 high in its slopes and crowned 17 00:00:43,094 --> 00:00:44,961 by jagged peaks that geologists 18 00:00:45,029 --> 00:00:46,830 believe were once double the 19 00:00:46,864 --> 00:00:49,866 height they are today. 20 00:00:49,934 --> 00:00:51,368 Scientists piecing together 21 00:00:51,402 --> 00:00:53,136 their story uncover evidence of 22 00:00:53,204 --> 00:00:56,273 massive ice sheets, collapsing 23 00:00:56,307 --> 00:00:58,008 mountains and explosive 24 00:00:58,042 --> 00:01:01,178 volcanic eruptions. 25 00:01:01,212 --> 00:01:02,479 A geological history that 26 00:01:02,580 --> 00:01:04,548 brings us one step closer to 27 00:01:04,582 --> 00:01:06,483 understanding how the Earth was made. 28 00:01:06,584 --> 00:01:10,552 S02x06 The Rockies Original Air Date on December 22, 2009 29 00:01:10,555 --> 00:01:13,857 -- Sync, corrected by elderman -- -- for MY-SUBS.com --- 30 00:01:13,925 --> 00:01:15,759 The Rockies--a majestic 31 00:01:15,860 --> 00:01:17,761 mountain range towering high 32 00:01:17,829 --> 00:01:20,731 above the American West. 33 00:01:20,765 --> 00:01:22,032 It's the longest chain in North 34 00:01:22,133 --> 00:01:23,934 America and the third longest 35 00:01:24,035 --> 00:01:26,203 in the world, stretching over 36 00:01:26,304 --> 00:01:29,206 3,000 miles from New Mexico, 37 00:01:29,273 --> 00:01:30,841 through Colorado, Wyoming and 38 00:01:30,908 --> 00:01:35,746 Montana and north into Canada. 39 00:01:35,847 --> 00:01:37,280 For decades, geologists have 40 00:01:37,315 --> 00:01:38,648 been puzzled about how this 41 00:01:38,750 --> 00:01:40,650 giant mountain range rose from 42 00:01:40,752 --> 00:01:42,586 the plains. 43 00:01:42,653 --> 00:01:44,187 The investigation begins with a 44 00:01:44,222 --> 00:01:46,757 specific type of rock. 45 00:01:46,858 --> 00:01:48,658 >> Here we are in the 46 00:01:48,659 --> 00:01:51,027 heart of the Rocky Mountains, 47 00:01:51,129 --> 00:01:52,395 we're in an amazing place to 48 00:01:52,463 --> 00:01:54,731 begin with, and right here at 49 00:01:54,732 --> 00:01:57,067 Red Rocks we're in the midst of 50 00:01:57,168 --> 00:01:59,169 an amphitheatre of rock. 51 00:01:59,270 --> 00:02:01,638 >> [singing rock music] 52 00:02:06,611 --> 00:02:08,712 >> 13 miles west of Denver, 53 00:02:08,780 --> 00:02:11,081 Colorado, two 300-foot-high 54 00:02:11,182 --> 00:02:13,550 sandstone monoliths slope 45 55 00:02:13,618 --> 00:02:15,819 degrees into the sky. 56 00:02:15,887 --> 00:02:17,621 Each is taller than Niagara 57 00:02:17,722 --> 00:02:19,356 Falls. 58 00:02:19,423 --> 00:02:21,224 Together, they form the walls of 59 00:02:21,259 --> 00:02:25,162 a unique musical venue. 60 00:02:25,263 --> 00:02:26,997 [crowd cheering] 61 00:02:27,064 --> 00:02:28,165 >> But there is more to these 62 00:02:28,232 --> 00:02:30,867 rocks than fine acoustics. 63 00:02:30,902 --> 00:02:32,803 These rocks tell the story of 64 00:02:32,870 --> 00:02:34,204 how the Rocky Mountains were 65 00:02:34,272 --> 00:02:36,706 made. 66 00:02:36,808 --> 00:02:37,908 The story begins with a 67 00:02:37,975 --> 00:02:40,777 mystery, 8,000 feet high in the 68 00:02:40,812 --> 00:02:42,779 Colorado Rockies 60 miles 69 00:02:42,814 --> 00:02:44,447 northwest of Boulder. 70 00:02:44,515 --> 00:02:46,082 All kinds of strange 71 00:02:46,150 --> 00:02:48,151 impressions are found in rocks 72 00:02:48,219 --> 00:02:50,520 scattered over the landscape. 73 00:02:50,588 --> 00:02:51,788 >> We find more than a hundred 74 00:02:51,889 --> 00:02:54,057 species of marine animals right 75 00:02:54,091 --> 00:02:56,359 here at this site. We find 76 00:02:56,427 --> 00:02:58,061 sharks. We find lobsters, 77 00:02:58,162 --> 00:03:00,063 crabs. We find beautiful fossil 78 00:03:00,131 --> 00:03:01,631 clams which are all over the 79 00:03:01,699 --> 00:03:02,599 place. 80 00:03:02,633 --> 00:03:04,167 >> These fossils are crucial 81 00:03:04,268 --> 00:03:06,069 evidence of what existed here 82 00:03:06,137 --> 00:03:08,438 before The Rockies emerged. 83 00:03:08,539 --> 00:03:10,073 >> We're sitting at 84 00:03:10,174 --> 00:03:11,875 about 8,000 feet in the middle 85 00:03:11,876 --> 00:03:13,343 of the Rocky Mountains. 86 00:03:13,411 --> 00:03:15,245 And so when these fossils where 87 00:03:15,313 --> 00:03:17,514 formed, this was below the level 88 00:03:17,515 --> 00:03:19,416 of the ocean. This was below sea 89 00:03:19,517 --> 00:03:21,718 level. 90 00:03:21,786 --> 00:03:23,353 >> This area was covered by a 91 00:03:23,421 --> 00:03:26,122 vast inland sea. 92 00:03:26,157 --> 00:03:27,858 It existed for over 30 million 93 00:03:27,892 --> 00:03:30,527 years and stretched from Utah 94 00:03:30,595 --> 00:03:32,262 to Missouri and from the Gulf 95 00:03:32,330 --> 00:03:35,599 of Mexico to the Arctic Sea. 96 00:03:35,700 --> 00:03:37,701 >> And at this very site, 97 00:03:37,768 --> 00:03:38,768 it would have been very warm, 98 00:03:38,803 --> 00:03:40,337 almost tropical, so 99 00:03:40,438 --> 00:03:41,972 envision maybe a day on the 100 00:03:42,073 --> 00:03:43,807 beach in Florida or something 101 00:03:43,875 --> 00:03:46,209 like that. 102 00:03:46,244 --> 00:03:47,978 >> This warm climate attracted a 103 00:03:48,045 --> 00:03:49,613 unique type of creature that 104 00:03:49,680 --> 00:03:51,581 left behind large, round 105 00:03:51,616 --> 00:03:54,050 imprints in the rocks. 106 00:03:54,151 --> 00:03:55,418 These fossils would play an 107 00:03:55,519 --> 00:03:56,753 important part in the 108 00:03:56,787 --> 00:03:58,054 investigation. 109 00:03:58,155 --> 00:03:59,122 >> This fossil here is 110 00:03:59,156 --> 00:04:01,258 a giant fossil Ammonite and 111 00:04:01,325 --> 00:04:03,660 this animal, this coiled shell 112 00:04:03,694 --> 00:04:04,895 right here, is a relative of 113 00:04:04,962 --> 00:04:05,528 modern-day squids. 114 00:04:05,596 --> 00:04:07,230 So, the closest living relatives 115 00:04:07,298 --> 00:04:09,432 today are squids, nautiloids, 116 00:04:09,500 --> 00:04:11,434 octopuses, things like that. 117 00:04:11,502 --> 00:04:12,869 And so in this big coiled shell 118 00:04:12,970 --> 00:04:13,970 here, the animal would have 119 00:04:14,038 --> 00:04:15,605 lived at this end, and its 120 00:04:15,673 --> 00:04:16,706 tentacles would have stretched 121 00:04:16,774 --> 00:04:18,074 out right here. 122 00:04:18,142 --> 00:04:20,410 And this animal is really quite 123 00:04:20,511 --> 00:04:21,945 remarkable. It's about the size 124 00:04:21,979 --> 00:04:23,580 of a truck tire, and this is 125 00:04:23,614 --> 00:04:24,781 incredible because most 126 00:04:24,882 --> 00:04:27,751 Ammonites aren't this big. 127 00:04:27,785 --> 00:04:29,319 >> Nowhere else have scientists 128 00:04:29,420 --> 00:04:30,954 found a greater number of these 129 00:04:31,022 --> 00:04:34,057 prehistoric creatures than here. 130 00:04:34,125 --> 00:04:35,125 Miller has come up with a 131 00:04:35,159 --> 00:04:37,060 theory why so many of them came 132 00:04:37,128 --> 00:04:38,962 to this area. 133 00:04:39,063 --> 00:04:40,130 >> We think this particular 134 00:04:40,231 --> 00:04:42,332 fossil here was a female 135 00:04:42,433 --> 00:04:44,134 Ammonite. And we think that in 136 00:04:44,235 --> 00:04:46,236 part because male squids are 137 00:04:46,304 --> 00:04:48,138 smaller than female squids by a 138 00:04:48,205 --> 00:04:50,040 lot. So just looking around the 139 00:04:50,107 --> 00:04:51,207 fossil deposits here, we've 140 00:04:51,242 --> 00:04:52,676 found a male Ammonite, this 141 00:04:52,777 --> 00:04:53,843 small one here. 142 00:04:53,878 --> 00:04:55,578 So compare the size of this guy 143 00:04:55,613 --> 00:04:57,747 to this very big one here. And 144 00:04:57,782 --> 00:04:58,782 when we look across this 145 00:04:58,883 --> 00:05:01,151 landscape, we find mostly these 146 00:05:01,218 --> 00:05:03,153 big Ammonites. And so we think 147 00:05:03,220 --> 00:05:04,521 that maybe all these females 148 00:05:04,555 --> 00:05:05,956 got together to spawn and then 149 00:05:06,057 --> 00:05:09,693 died after they spawned. 150 00:05:09,760 --> 00:05:11,328 >> When the Ammonites became 151 00:05:11,429 --> 00:05:12,963 extinct, the map of North 152 00:05:13,064 --> 00:05:14,397 America looked completely 153 00:05:14,498 --> 00:05:17,033 different. 154 00:05:17,134 --> 00:05:18,768 To the north, the Canadian Rocky 155 00:05:18,869 --> 00:05:22,238 Mountains already existed. 156 00:05:22,306 --> 00:05:23,740 To the south, the American 157 00:05:23,774 --> 00:05:28,745 Rockies had yet to rise. 158 00:05:28,779 --> 00:05:30,013 The date of the Ammonites' 159 00:05:30,047 --> 00:05:32,315 extinction holds a key to when 160 00:05:32,383 --> 00:05:35,485 they first emerged. 161 00:05:35,586 --> 00:05:36,920 >> These animals died 162 00:05:36,954 --> 00:05:38,688 about 70 million years ago 163 00:05:38,789 --> 00:05:39,856 in the middle of the western 164 00:05:39,957 --> 00:05:41,057 interior seaway. And so we know 165 00:05:41,125 --> 00:05:42,192 at that time, about 70 166 00:05:42,226 --> 00:05:43,593 million years ago, that this 167 00:05:43,694 --> 00:05:45,962 site was below sea level. 168 00:05:46,030 --> 00:05:47,464 So we know then that the Rocky 169 00:05:47,498 --> 00:05:48,932 Mountains had to rise from that 170 00:05:48,966 --> 00:05:51,568 seaway some time after 171 00:05:51,602 --> 00:05:54,237 70 million years ago. 172 00:05:54,305 --> 00:05:55,939 >> Today, all that is left from 173 00:05:56,040 --> 00:05:57,674 the ancient sea floor are these 174 00:05:57,742 --> 00:05:59,576 fossilized remains high in the 175 00:05:59,677 --> 00:06:04,047 Colorado Rockies. 176 00:06:04,115 --> 00:06:06,282 Next, geologists needed to find 177 00:06:06,317 --> 00:06:09,686 out what pushed the seafloor up. 178 00:06:09,754 --> 00:06:11,187 The investigation moves to 179 00:06:11,222 --> 00:06:12,856 these slabs of rock flanking 180 00:06:12,923 --> 00:06:14,324 the Rockies just outside 181 00:06:14,392 --> 00:06:17,560 Denver, Colorado. 182 00:06:17,595 --> 00:06:19,596 They are known as the flatirons, 183 00:06:19,663 --> 00:06:20,764 and they are part of the same 184 00:06:20,831 --> 00:06:22,465 formation that make up the Red 185 00:06:22,500 --> 00:06:25,468 Rocks Amphitheater. 186 00:06:25,503 --> 00:06:26,870 These slabs of rock are 187 00:06:26,937 --> 00:06:29,105 unusual, because they contain 188 00:06:29,140 --> 00:06:31,374 holes--holes that make the 189 00:06:31,409 --> 00:06:33,410 flatirons appealing to climbers 190 00:06:33,477 --> 00:06:36,112 and geologists alike. 191 00:06:36,213 --> 00:06:37,113 >> So when we go 192 00:06:37,214 --> 00:06:38,314 climbing in the flatirons, we're 193 00:06:38,382 --> 00:06:39,949 climbing on really nice 194 00:06:39,950 --> 00:06:41,751 hand-holds, in some cases 195 00:06:41,852 --> 00:06:42,952 hand-holds that have been 196 00:06:43,020 --> 00:06:45,021 formed either by the pebbles in 197 00:06:45,122 --> 00:06:47,824 the rock or by zones of 198 00:06:47,825 --> 00:06:49,225 fine-grained material that are 199 00:06:49,293 --> 00:06:51,394 easily removed by erosion, the 200 00:06:51,462 --> 00:06:53,396 shales and the silt stones. 201 00:06:53,464 --> 00:06:55,665 Those layers get removed 202 00:06:55,766 --> 00:06:58,201 leaving a notch for the hands 203 00:06:58,269 --> 00:07:00,103 to go in, and it makes 204 00:07:00,137 --> 00:07:02,472 for fantastic climbing. 205 00:07:02,506 --> 00:07:04,274 >> The holes are a clue as to 206 00:07:04,308 --> 00:07:05,675 how these strangely tilted 207 00:07:05,776 --> 00:07:07,744 flatirons were formed. 208 00:07:07,845 --> 00:07:09,946 >> The layers themselves, the 209 00:07:10,047 --> 00:07:11,381 different grain sizes in the 210 00:07:11,449 --> 00:07:14,951 layers, the silt, the sand, the 211 00:07:15,019 --> 00:07:17,220 pebbles--this tells us that 212 00:07:17,288 --> 00:07:20,924 these are sedimentary rocks. 213 00:07:21,025 --> 00:07:22,926 >> Sediments form in water when 214 00:07:23,027 --> 00:07:24,861 sand and small pieces of rock 215 00:07:24,929 --> 00:07:26,863 settle on the ground. 216 00:07:26,931 --> 00:07:28,264 Over millions of years, they get 217 00:07:28,299 --> 00:07:32,368 compressed into layers of rock. 218 00:07:32,403 --> 00:07:34,204 Taking a closer look, Lester can 219 00:07:34,271 --> 00:07:35,672 find out more about the 220 00:07:35,739 --> 00:07:38,374 surroundings they formed in. 221 00:07:38,409 --> 00:07:39,542 >> These were not just deposited 222 00:07:39,577 --> 00:07:40,810 in any kind of sedimentary 223 00:07:40,845 --> 00:07:41,744 situation, but they were 224 00:07:41,812 --> 00:07:44,013 deposited in rivers capable of 225 00:07:44,081 --> 00:07:45,915 transporting big particles and 226 00:07:45,950 --> 00:07:50,019 busting 'em up as it goes along. 227 00:07:50,121 --> 00:07:52,355 >> Sheets of sand and gravel 228 00:07:52,389 --> 00:07:54,457 built up a thick sedimentary bed 229 00:07:54,492 --> 00:07:56,626 like a layered cake, 230 00:07:56,660 --> 00:07:58,361 but stream deposits are rarely 231 00:07:58,395 --> 00:08:00,130 more than a few degrees from 232 00:08:00,197 --> 00:08:01,297 horizontal. 233 00:08:01,365 --> 00:08:02,465 >> These rocks--you can see the 234 00:08:02,566 --> 00:08:03,633 layers and the layers in the 235 00:08:03,667 --> 00:08:06,402 flatirons behind me--are 60 236 00:08:06,470 --> 00:08:08,204 degrees. 237 00:08:08,272 --> 00:08:10,106 >> Something caused these vast 238 00:08:10,207 --> 00:08:15,645 slabs to be tilted. 239 00:08:15,746 --> 00:08:17,580 The investigation moves 10 240 00:08:17,648 --> 00:08:19,282 miles northeast to Flagstaff 241 00:08:19,350 --> 00:08:21,284 Mountain, located in the outer 242 00:08:21,385 --> 00:08:25,188 ranges of the Colorado Rockies. 243 00:08:25,289 --> 00:08:26,122 >> I'm standing here 244 00:08:26,190 --> 00:08:27,023 right next to a miniature 245 00:08:27,091 --> 00:08:28,725 flatiron. It's tilted like the 246 00:08:28,759 --> 00:08:31,127 flatirons at about 60 degrees. 247 00:08:31,195 --> 00:08:32,462 It's steep. How did it 248 00:08:32,530 --> 00:08:33,663 get that way if it was 249 00:08:33,731 --> 00:08:35,198 originally a stream gravel 250 00:08:35,299 --> 00:08:36,933 deposit? 251 00:08:37,001 --> 00:08:38,601 >> The answer lies in the darker 252 00:08:38,669 --> 00:08:40,370 rock underneath. 253 00:08:40,471 --> 00:08:41,738 It is granite and looks 254 00:08:41,839 --> 00:08:43,273 completely different to the 255 00:08:43,374 --> 00:08:46,109 flatiron rock above. 256 00:08:46,177 --> 00:08:47,210 >> There's no layering 257 00:08:47,278 --> 00:08:48,545 in this rock, unlike the 258 00:08:48,646 --> 00:08:50,113 flatiron rock which does have 259 00:08:50,181 --> 00:08:51,114 layering. 260 00:08:51,182 --> 00:08:52,282 There's no pebbles in this 261 00:08:52,349 --> 00:08:53,917 rock, unlike the flatiron rock 262 00:08:54,018 --> 00:08:59,189 which does have pebbles. 263 00:08:59,290 --> 00:09:00,523 >> A close-up investigation of 264 00:09:00,591 --> 00:09:01,991 the granite reveals that it is 265 00:09:02,059 --> 00:09:03,893 full of minerals. 266 00:09:03,994 --> 00:09:05,495 This offers another clue to how 267 00:09:05,529 --> 00:09:08,965 the Rockies emerged. 268 00:09:09,066 --> 00:09:10,266 >> So I've picked up 269 00:09:10,334 --> 00:09:11,768 this granite here and taking a 270 00:09:11,802 --> 00:09:14,704 look at it, I see quartz and 271 00:09:14,772 --> 00:09:16,039 feldspar and a little bit of 272 00:09:16,073 --> 00:09:17,340 mica in here, very 273 00:09:17,408 --> 00:09:20,076 characteristic of a rock like 274 00:09:20,144 --> 00:09:22,045 this that has cooled from a 275 00:09:22,079 --> 00:09:26,049 magma, from a liquid rock. 276 00:09:26,083 --> 00:09:28,985 >> Among the minerals is iron. 277 00:09:29,053 --> 00:09:30,420 It is responsible for the dark 278 00:09:30,521 --> 00:09:33,256 color of the rock. 279 00:09:33,324 --> 00:09:34,791 The precise quantity of iron 280 00:09:34,858 --> 00:09:36,392 tells scientists the depth at 281 00:09:36,427 --> 00:09:39,596 which the rock was formed. 282 00:09:39,697 --> 00:09:40,663 >> So we've taken this 283 00:09:40,698 --> 00:09:42,765 rock into the laboratory and we 284 00:09:42,833 --> 00:09:44,367 do the chemistry on this rock, 285 00:09:44,401 --> 00:09:45,635 and we can actually determine 286 00:09:45,669 --> 00:09:47,804 that not only did cool and 287 00:09:47,871 --> 00:09:49,639 crystallize at depth, that 288 00:09:49,707 --> 00:09:51,441 depth we can estimate at about 289 00:09:51,542 --> 00:09:56,746 15 miles down. 290 00:09:56,780 --> 00:09:58,581 It's now at the surface. How 291 00:09:58,649 --> 00:10:00,149 did it get here? It's been 292 00:10:00,251 --> 00:10:01,684 pushed up by the rise of the 293 00:10:01,752 --> 00:10:03,219 Rocky Mountains and in doing 294 00:10:03,287 --> 00:10:04,787 so, look what it's done to the 295 00:10:04,855 --> 00:10:06,956 flatiron. 296 00:10:07,057 --> 00:10:08,491 >> Scientists investigating the 297 00:10:08,559 --> 00:10:10,226 Rocky Mountains have found two 298 00:10:10,327 --> 00:10:14,030 clues about their early history. 299 00:10:14,098 --> 00:10:16,032 Ammonites on a site 8,000 feet 300 00:10:16,100 --> 00:10:17,934 high are evidence that the area 301 00:10:18,002 --> 00:10:20,203 was once under the sea. 302 00:10:20,304 --> 00:10:22,305 Traces of iron in granite 303 00:10:22,373 --> 00:10:23,539 is evidence that 304 00:10:23,574 --> 00:10:25,642 rock pushed up from 15 miles 305 00:10:25,743 --> 00:10:26,909 below the surface 306 00:10:27,011 --> 00:10:29,479 tilting the flatirons. 307 00:10:29,546 --> 00:10:31,014 And it didn't just happen here 308 00:10:31,081 --> 00:10:32,482 but along approximately 1,000 309 00:10:32,549 --> 00:10:35,852 miles of the American Rockies. 310 00:10:35,953 --> 00:10:37,387 Geologists now needed to find 311 00:10:37,454 --> 00:10:39,489 out what monumental forces were 312 00:10:39,590 --> 00:10:41,391 responsible for this massive 313 00:10:41,458 --> 00:10:44,059 upheaval. 314 00:10:50,478 --> 00:10:52,179 100 million years ago, most of 315 00:10:52,280 --> 00:10:54,014 North America was covered by a 316 00:10:54,082 --> 00:10:57,451 vVast inland sea. 317 00:10:57,552 --> 00:10:59,286 70 million years ago, the sea 318 00:10:59,354 --> 00:11:02,022 retreated and the Rocky 319 00:11:02,090 --> 00:11:04,191 Mountains began to rise, forming 320 00:11:04,259 --> 00:11:07,194 a great mountain range. 321 00:11:07,295 --> 00:11:08,462 Scientists trying to piece 322 00:11:08,563 --> 00:11:10,564 together their geological past 323 00:11:10,632 --> 00:11:12,199 needed to solve the mystery of 324 00:11:12,267 --> 00:11:18,205 what lifted them up. 325 00:11:18,273 --> 00:11:19,807 A force capable of that amount 326 00:11:19,841 --> 00:11:21,175 of heavy lifting would have to 327 00:11:21,276 --> 00:11:24,378 have been on a global scale. 328 00:11:24,479 --> 00:11:26,080 Geologists believe this force 329 00:11:26,114 --> 00:11:29,884 was caused by plate tectonics. 330 00:11:29,918 --> 00:11:31,518 The Earth's crust is broken up 331 00:11:31,553 --> 00:11:33,354 into a series of interlocking 332 00:11:33,388 --> 00:11:34,989 plates. 333 00:11:35,023 --> 00:11:36,924 These plates are continuously 334 00:11:36,992 --> 00:11:38,726 on the move. 335 00:11:38,827 --> 00:11:40,361 Over millions of years, they 336 00:11:40,428 --> 00:11:42,796 collide and break apart, 337 00:11:42,831 --> 00:11:44,098 forming new continents and 338 00:11:44,199 --> 00:11:45,833 geological features around the 339 00:11:45,901 --> 00:11:47,468 world. 340 00:11:47,535 --> 00:11:49,169 When The Rockies formed, two of 341 00:11:49,204 --> 00:11:50,838 these plates smashed into each 342 00:11:50,906 --> 00:11:52,273 other at the American West 343 00:11:52,374 --> 00:11:53,807 Coast. 344 00:11:53,808 --> 00:11:55,009 >> What we know is 345 00:11:55,110 --> 00:11:56,443 that at the time of this 346 00:11:56,511 --> 00:11:58,178 granite uplift on the western 347 00:11:58,179 --> 00:12:00,714 margin of North America, ocean 348 00:12:00,782 --> 00:12:03,083 crust and oceanic plate was 349 00:12:03,184 --> 00:12:05,085 subducting beneath the North 350 00:12:05,153 --> 00:12:06,654 American plate, and it was doing 351 00:12:06,721 --> 00:12:09,890 so at a high rate of speed. 352 00:12:09,925 --> 00:12:11,926 As such, it was transferring 353 00:12:11,993 --> 00:12:13,694 stress into the interior of the 354 00:12:13,728 --> 00:12:15,329 continent. 355 00:12:15,363 --> 00:12:16,263 >> As the two plates moved 356 00:12:16,364 --> 00:12:17,464 towards each other, they 357 00:12:17,532 --> 00:12:19,700 squeezed the crust. 358 00:12:19,734 --> 00:12:21,168 Over millions of years, it 359 00:12:21,269 --> 00:12:23,070 folded and buckled forming tall 360 00:12:23,104 --> 00:12:24,905 mountains. 361 00:12:24,973 --> 00:12:26,440 This was the birth of the 362 00:12:26,541 --> 00:12:29,009 American Rockies. 363 00:12:29,077 --> 00:12:30,911 But a mystery remained. 364 00:12:30,979 --> 00:12:32,146 How did the collision of two 365 00:12:32,180 --> 00:12:33,647 tectonic plates at the western 366 00:12:33,715 --> 00:12:35,549 edge of North America cause the 367 00:12:35,617 --> 00:12:38,619 rise of the Rockies 500 to 1,000 368 00:12:38,720 --> 00:12:40,454 miles inland? 369 00:12:40,522 --> 00:12:41,355 >> Mountain ranges 370 00:12:41,456 --> 00:12:42,556 that form on the margins of 371 00:12:42,624 --> 00:12:43,791 continents are pretty easy to 372 00:12:43,825 --> 00:12:45,726 explain, or where continents 373 00:12:45,827 --> 00:12:47,061 have collided. Where India 374 00:12:47,095 --> 00:12:48,362 slams into Asia, we get the 375 00:12:48,463 --> 00:12:50,631 Himalayas. Where oceanic crust 376 00:12:50,699 --> 00:12:52,099 dives beneath the continental 377 00:12:52,167 --> 00:12:54,001 margin in the northwest, 378 00:12:54,069 --> 00:12:55,235 the Cascades, or in 379 00:12:55,270 --> 00:12:56,337 South America, the Andes 380 00:12:56,371 --> 00:12:57,604 Mountains. 381 00:12:57,639 --> 00:12:59,440 But these mountains here in the 382 00:12:59,541 --> 00:13:01,141 middle of a continent are much 383 00:13:01,176 --> 00:13:02,443 harder to explain and they've 384 00:13:02,510 --> 00:13:05,446 been an enigma for decades. 385 00:13:05,513 --> 00:13:07,047 >> Only recently geologists have 386 00:13:07,082 --> 00:13:10,684 come up with a plausible theory. 387 00:13:10,719 --> 00:13:12,353 They suspect the Rockies formed 388 00:13:12,454 --> 00:13:14,321 along a line where the crust is 389 00:13:14,356 --> 00:13:15,689 very fragile. 390 00:13:15,724 --> 00:13:16,724 >> What happens when 391 00:13:16,791 --> 00:13:18,092 the continent gets compressed, 392 00:13:18,159 --> 00:13:19,393 especially if there's a weak 393 00:13:19,461 --> 00:13:20,728 zone or a zone that's prone to 394 00:13:20,795 --> 00:13:23,430 buckling, it rises. 395 00:13:23,531 --> 00:13:24,498 That's what's brought this 396 00:13:24,532 --> 00:13:26,900 granite to the surface. 397 00:13:26,968 --> 00:13:29,770 >> Geologists now understood how 398 00:13:29,804 --> 00:13:31,905 the Rockies rose and they had a 399 00:13:31,973 --> 00:13:34,541 date for when it happened, 400 00:13:34,609 --> 00:13:35,709 but what were these early 401 00:13:35,810 --> 00:13:37,344 mountains like? 402 00:13:37,445 --> 00:13:38,612 How do they compare to the 403 00:13:38,713 --> 00:13:40,814 mountains of today? 404 00:13:40,882 --> 00:13:42,182 On a site in The Rockies 70 405 00:13:42,250 --> 00:13:44,184 miles northwest of Denver, 406 00:13:44,252 --> 00:13:47,254 geologists find a clue. 407 00:13:47,255 --> 00:13:48,322 >> The mountains that 408 00:13:48,356 --> 00:13:49,356 we see here today aren't the 409 00:13:49,424 --> 00:13:50,858 mountains that were around 410 00:13:50,892 --> 00:13:52,092 millions of years ago. They're 411 00:13:52,160 --> 00:13:53,260 always evolving. Rivers are 412 00:13:53,261 --> 00:13:54,995 shifting. Peaks are shifting. 413 00:13:55,063 --> 00:13:56,363 It's a very dynamic process. 414 00:13:56,431 --> 00:13:57,364 It's almost as if the mountains 415 00:13:57,432 --> 00:14:00,567 are alive themselves. 416 00:14:00,602 --> 00:14:01,935 >> Miller sets out to estimate 417 00:14:02,037 --> 00:14:03,103 the height of the early 418 00:14:03,138 --> 00:14:04,872 mountains. But how can you 419 00:14:04,939 --> 00:14:06,673 measure something that is no 420 00:14:06,775 --> 00:14:08,409 longer there? 421 00:14:08,510 --> 00:14:10,477 Once more, fossils provide the 422 00:14:10,512 --> 00:14:13,047 evidence he is looking for. 423 00:14:13,114 --> 00:14:14,214 >> What's amazing about 424 00:14:14,315 --> 00:14:15,582 collecting fossils is that 425 00:14:15,650 --> 00:14:16,750 you're really the first person 426 00:14:16,785 --> 00:14:18,052 to see this when you crack open 427 00:14:18,119 --> 00:14:19,486 a rock. 428 00:14:19,554 --> 00:14:20,320 It's the first time it sees 429 00:14:20,388 --> 00:14:21,588 light again after 60 million 430 00:14:21,656 --> 00:14:23,957 years. 431 00:14:24,025 --> 00:14:25,392 >> Miller has uncovered a 60 432 00:14:25,460 --> 00:14:27,127 million-year-old fossilized 433 00:14:27,195 --> 00:14:29,463 leaf. 434 00:14:29,497 --> 00:14:30,597 >> It's from a tree that grew 435 00:14:30,665 --> 00:14:32,566 here just 10 million years after 436 00:14:32,667 --> 00:14:35,502 the Rockies began to form. 437 00:14:35,570 --> 00:14:37,371 And intriguingly, this leaf 438 00:14:37,405 --> 00:14:39,273 holds a clue to the height of 439 00:14:39,307 --> 00:14:41,708 these early mountains. 440 00:14:41,810 --> 00:14:43,177 Or more precisely, it's the 441 00:14:43,244 --> 00:14:45,045 edges of the leaf, known as 442 00:14:45,080 --> 00:14:47,147 leaf margins. 443 00:14:47,215 --> 00:14:48,715 Botanists know that in colder 444 00:14:48,783 --> 00:14:50,250 temperatures, the margins tend 445 00:14:50,318 --> 00:14:52,419 to have more teeth than leaves 446 00:14:52,520 --> 00:14:54,421 that grow in warmer areas. 447 00:14:54,489 --> 00:14:55,689 >> Leaves with teeth 448 00:14:55,790 --> 00:14:57,157 do better in colder climates 449 00:14:57,225 --> 00:14:58,258 because teeth are actually 450 00:14:58,326 --> 00:14:59,526 really advantageous in 451 00:14:59,594 --> 00:15:00,894 ump-starting growth at the 452 00:15:00,962 --> 00:15:02,162 beginning of the growing season. 453 00:15:02,230 --> 00:15:03,330 In this case, you can see this 454 00:15:03,398 --> 00:15:04,598 beautiful fossil leaf here with 455 00:15:04,666 --> 00:15:06,433 teeth, and each of the teeth are 456 00:15:06,534 --> 00:15:07,434 little hot-beds of 457 00:15:07,502 --> 00:15:08,802 photosynthesis. So when that 458 00:15:08,870 --> 00:15:10,437 leaf first comes out of the bud, 459 00:15:10,505 --> 00:15:12,339 it gets a jump-start on leaves 460 00:15:12,407 --> 00:15:15,943 that don't have teeth. 461 00:15:15,977 --> 00:15:17,478 >> Miller uses this information 462 00:15:17,512 --> 00:15:19,213 to find out about the height of 463 00:15:19,247 --> 00:15:21,515 the young Rocky Mountains. 464 00:15:21,583 --> 00:15:22,783 In a simple but powerful 465 00:15:22,884 --> 00:15:24,618 technique, he compares the 466 00:15:24,686 --> 00:15:26,620 number of leaves with teeth to 467 00:15:26,688 --> 00:15:28,322 those without. 468 00:15:28,356 --> 00:15:29,423 >> If you go to a 469 00:15:29,524 --> 00:15:30,424 particular area and you pick up 470 00:15:30,492 --> 00:15:31,959 all the species of leaves that 471 00:15:32,060 --> 00:15:33,227 are there from the trees that 472 00:15:33,328 --> 00:15:34,294 are growing in that area and 473 00:15:34,329 --> 00:15:35,329 you compare the number of 474 00:15:35,430 --> 00:15:36,864 species that have teeth to the 475 00:15:36,965 --> 00:15:38,332 number of species that have 476 00:15:38,433 --> 00:15:39,967 smooth margins, that gives us 477 00:15:40,068 --> 00:15:40,968 some idea of what the 478 00:15:41,035 --> 00:15:42,669 temperature is. 479 00:15:42,704 --> 00:15:44,238 >> So the higher the proportion 480 00:15:44,339 --> 00:15:46,306 of plants with jagged edges 481 00:15:46,341 --> 00:15:47,975 compared to plants with smooth 482 00:15:48,042 --> 00:15:49,510 edges, the colder the 483 00:15:49,611 --> 00:15:51,612 temperature of the site. 484 00:15:51,679 --> 00:15:53,313 And the colder the temperature, 485 00:15:53,414 --> 00:15:55,849 the higher the mountain. 486 00:15:55,884 --> 00:15:56,884 >> So if you 487 00:15:56,951 --> 00:15:58,318 got into a hot-air balloon here 488 00:15:58,386 --> 00:15:59,486 today and you floated straight 489 00:15:59,521 --> 00:16:00,954 up into the atmosphere, the 490 00:16:01,022 --> 00:16:02,156 temperature would decrease in a 491 00:16:02,223 --> 00:16:03,423 aery predictable way. And it 492 00:16:03,525 --> 00:16:05,058 turns out that for about every 493 00:16:05,126 --> 00:16:06,126 mile you go up in the 494 00:16:06,161 --> 00:16:07,227 atmosphere, you lose about 495 00:16:07,328 --> 00:16:09,129 20 degrees fahrenheit. 496 00:16:09,230 --> 00:16:10,564 So if we know how temperature 497 00:16:10,598 --> 00:16:11,865 changes with elevation, we can 498 00:16:11,966 --> 00:16:13,867 back out elevation from those 499 00:16:13,935 --> 00:16:16,703 estimates of temperature. 500 00:16:16,771 --> 00:16:17,971 >> To work out the height of the 501 00:16:18,039 --> 00:16:19,973 early mountain, Miller needs to 502 00:16:20,041 --> 00:16:22,743 compare samples from two areas-- 503 00:16:22,777 --> 00:16:24,411 one at the base of the mountain 504 00:16:24,512 --> 00:16:27,047 and one at the top. 505 00:16:27,115 --> 00:16:28,515 Fossils found at the base of 506 00:16:28,583 --> 00:16:30,117 the Rockies near to present day 507 00:16:30,151 --> 00:16:32,219 Denver have an amazing story to 508 00:16:32,287 --> 00:16:34,054 tell. 509 00:16:34,122 --> 00:16:35,689 These ancient leaves are 510 00:16:35,790 --> 00:16:37,858 incredibly similar to plants 511 00:16:37,926 --> 00:16:42,029 growing in the tropics today. 512 00:16:42,063 --> 00:16:43,297 >> So after the Rockies 513 00:16:43,331 --> 00:16:44,831 rose, down in the area of 514 00:16:44,866 --> 00:16:46,300 Denver, it was sub-tropical and 515 00:16:46,334 --> 00:16:48,402 tropical forests. We had palms 516 00:16:48,503 --> 00:16:50,404 and cycads and canopies like we 517 00:16:50,471 --> 00:16:52,673 see in the tropics today. 518 00:16:52,740 --> 00:16:53,941 Up here, we had a forest that 519 00:16:54,008 --> 00:16:55,042 looked probably more like a 520 00:16:55,109 --> 00:16:56,410 forest that grows in North or 521 00:16:56,511 --> 00:16:57,578 South Carolina on the east 522 00:16:57,645 --> 00:17:00,581 coast of the U.S. 523 00:17:00,648 --> 00:17:01,848 >> By comparing the ancient 524 00:17:01,950 --> 00:17:03,317 fossil leaves from the top of 525 00:17:03,384 --> 00:17:04,851 the mountain with fossil leaves 526 00:17:04,953 --> 00:17:06,486 from the foot of the mountain, 527 00:17:06,588 --> 00:17:07,654 Miller has come up 528 00:17:07,689 --> 00:17:12,392 with a surprising conclusion. 529 00:17:12,460 --> 00:17:13,327 >> Turns out that 530 00:17:13,394 --> 00:17:14,695 the fossil leaves here are 531 00:17:14,762 --> 00:17:16,129 predominantly toothed, as 532 00:17:16,231 --> 00:17:17,130 compared to those that are in 533 00:17:17,232 --> 00:17:18,865 Denver, which are predominantly 534 00:17:18,967 --> 00:17:20,133 smooth margined. 535 00:17:20,235 --> 00:17:20,968 And it turns out the ones in 536 00:17:21,035 --> 00:17:22,035 Denver grew in a climate that 537 00:17:22,136 --> 00:17:23,303 was about, on average, about 538 00:17:23,371 --> 00:17:25,138 75 degrees fahrenheit. 539 00:17:25,206 --> 00:17:26,373 The ones up here grew in a 540 00:17:26,407 --> 00:17:27,507 climate that was probably about 541 00:17:27,575 --> 00:17:29,209 50 degrees fahrenheit. 542 00:17:29,310 --> 00:17:30,744 So we know how temperature 543 00:17:30,778 --> 00:17:32,045 changes with elevation. That 544 00:17:32,146 --> 00:17:34,214 means that this site when these 545 00:17:34,315 --> 00:17:35,549 fossil leaves were deposited, 546 00:17:35,583 --> 00:17:37,684 was about a mile higher than 547 00:17:37,752 --> 00:17:38,685 Denver. 548 00:17:38,753 --> 00:17:39,753 Today, it's only half a mile 549 00:17:39,821 --> 00:17:41,588 higher. So, 60 million years 550 00:17:41,656 --> 00:17:42,322 ago, the mountains would be 551 00:17:42,390 --> 00:17:48,629 twice as high as they are today. 552 00:17:48,663 --> 00:17:50,030 >> After the Rockies emerged 553 00:17:50,131 --> 00:17:51,765 from the sea, it took them 10 554 00:17:51,866 --> 00:17:54,301 million years to rise. 555 00:17:54,369 --> 00:17:55,936 60 million years ago, they 556 00:17:56,004 --> 00:17:57,871 reached spectacular heights of 557 00:17:57,939 --> 00:18:00,574 28,000 feet, rivaling the 558 00:18:00,642 --> 00:18:02,109 Himalayas today. 559 00:18:06,781 --> 00:18:08,115 The deep history of the Rocky 560 00:18:08,216 --> 00:18:09,850 Mountains is beginning to take 561 00:18:09,951 --> 00:18:12,953 shape. A weak line in the crust 562 00:18:13,021 --> 00:18:14,955 explains why The Rockies rose 563 00:18:15,023 --> 00:18:18,191 500 to 1,000 miles inland. 564 00:18:18,226 --> 00:18:19,593 Fossil leaves show that the 565 00:18:19,661 --> 00:18:21,194 young Rocky Mountains were once 566 00:18:21,229 --> 00:18:25,032 nearly twice their size. 567 00:18:25,099 --> 00:18:26,266 Half of the rock that formed 568 00:18:26,301 --> 00:18:28,669 them originally has vanished. 569 00:18:28,770 --> 00:18:30,103 Scientists are now trying to 570 00:18:30,138 --> 00:18:31,838 unravel the processes that cut 571 00:18:31,906 --> 00:18:33,674 them down to the size they are 572 00:18:33,741 --> 00:18:35,575 today. 573 00:18:43,625 --> 00:18:45,559 100 million years ago, a vast 574 00:18:45,627 --> 00:18:47,361 inland sea covered the area 575 00:18:47,395 --> 00:18:48,762 where the American Rockies 576 00:18:48,830 --> 00:18:51,198 stand tall today. 577 00:18:51,299 --> 00:18:52,899 70 million years ago, the sea 578 00:18:52,934 --> 00:18:55,035 retreated as The Rockies began 579 00:18:55,103 --> 00:18:58,739 to rise. 60 million years ago, 580 00:18:58,840 --> 00:19:00,073 the Rocky Mountains reached 581 00:19:00,108 --> 00:19:01,575 their pinnacle, towering into 582 00:19:01,643 --> 00:19:04,077 the sky with peaks over 28,000 583 00:19:04,112 --> 00:19:05,912 feet high, rivaling the 584 00:19:06,014 --> 00:19:08,982 Himalayas. Since then, the 585 00:19:09,017 --> 00:19:11,184 entire mountain range has lost 586 00:19:11,252 --> 00:19:14,655 nearly half its height. 587 00:19:14,722 --> 00:19:16,123 Geologists investigating the 588 00:19:16,190 --> 00:19:17,624 history of the Rockies are 589 00:19:17,659 --> 00:19:19,026 trying to discover what 590 00:19:19,093 --> 00:19:20,727 happened to the billions of 591 00:19:20,828 --> 00:19:23,830 tons of rock that went missing. 592 00:19:27,435 --> 00:19:29,369 The investigation starts with a 593 00:19:29,437 --> 00:19:30,737 mystery at the Owl Creek 594 00:19:30,838 --> 00:19:32,005 Mountains in the Wyoming 595 00:19:32,106 --> 00:19:34,441 Rockies. 596 00:19:34,475 --> 00:19:35,642 The mountains are sliced by a 597 00:19:35,710 --> 00:19:37,444 river that has formed a deep 598 00:19:37,478 --> 00:19:40,080 canyon. 599 00:19:40,081 --> 00:19:41,081 >> Well, the Wind River 600 00:19:41,115 --> 00:19:42,616 is very perplexing. 601 00:19:42,650 --> 00:19:43,750 It chose to take a straight 602 00:19:43,818 --> 00:19:45,285 path right through the core of 603 00:19:45,353 --> 00:19:47,454 a major mountain range. This is 604 00:19:47,455 --> 00:19:48,555 not the way that rivers 605 00:19:48,656 --> 00:19:50,557 normally act. Usually they'll 606 00:19:50,625 --> 00:19:51,925 take the easiest route, 607 00:19:51,993 --> 00:19:53,460 which is downhill. But this 608 00:19:53,561 --> 00:19:55,362 river cut right through a major 609 00:19:55,463 --> 00:19:57,097 mountain range and has been 610 00:19:57,198 --> 00:19:58,565 a mystery. It's a very 611 00:19:58,633 --> 00:19:59,900 perplexing issue to early 612 00:19:59,934 --> 00:20:03,637 geologists in the region. 613 00:20:03,738 --> 00:20:05,472 >> This river led to confusion 614 00:20:05,540 --> 00:20:08,008 as early as 1806 when Meriwether 615 00:20:08,109 --> 00:20:10,477 Lewis and William Clark mapped 616 00:20:10,545 --> 00:20:12,079 the area during their famous 617 00:20:12,113 --> 00:20:14,381 expedition to explore uncharted 618 00:20:14,449 --> 00:20:17,017 territory in the west. 619 00:20:17,085 --> 00:20:18,185 When they came to the area 620 00:20:18,286 --> 00:20:20,287 around the Owl Creek Mountains, 621 00:20:20,355 --> 00:20:22,022 they assumed there were two 622 00:20:22,090 --> 00:20:24,291 rivers. 623 00:20:24,359 --> 00:20:25,559 North of the mountain flowed a 624 00:20:25,626 --> 00:20:26,893 river which they named 625 00:20:26,928 --> 00:20:28,462 "Bighorn", thinking it was 626 00:20:28,563 --> 00:20:30,263 different to Wind River in the 627 00:20:30,331 --> 00:20:31,732 South. 628 00:20:31,833 --> 00:20:33,700 But later surveys showed that 629 00:20:33,735 --> 00:20:35,435 the Bighorn and Wind River are 630 00:20:35,470 --> 00:20:37,437 in fact one river that 631 00:20:37,472 --> 00:20:41,541 channeled through the mountain. 632 00:20:41,609 --> 00:20:43,510 Recently, geologists have come 633 00:20:43,544 --> 00:20:45,645 up with a possible answer--an 634 00:20:45,713 --> 00:20:47,547 answer that could also explain 635 00:20:47,648 --> 00:20:49,082 what happened to the once 636 00:20:49,183 --> 00:20:51,885 towering peaks of the Rockies. 637 00:20:51,919 --> 00:20:54,054 They proposed that millions of 638 00:20:54,088 --> 00:20:56,556 tons of rock eroded away, 639 00:20:56,624 --> 00:20:58,091 filled in the valleys, and 640 00:20:58,159 --> 00:20:59,459 covered the lower parts of the 641 00:20:59,527 --> 00:21:00,727 mountains. 642 00:21:00,795 --> 00:21:01,962 It completely changed the 643 00:21:01,996 --> 00:21:04,097 terrain. 644 00:21:04,165 --> 00:21:05,165 >> At one point in 645 00:21:05,233 --> 00:21:06,366 ancient history, the basins in 646 00:21:06,434 --> 00:21:07,467 Wyoming were filled with 647 00:21:07,535 --> 00:21:08,802 sediments that had eroded off 648 00:21:08,903 --> 00:21:09,870 the mountains. 649 00:21:09,904 --> 00:21:11,738 This allowed the river to be at 650 00:21:11,806 --> 00:21:13,006 a higher plain and meander 651 00:21:13,074 --> 00:21:14,174 wherever it wanted to on its 652 00:21:14,242 --> 00:21:17,010 course. 653 00:21:17,078 --> 00:21:18,412 >> As the water flowed, it 654 00:21:18,446 --> 00:21:20,447 carved deep into the sediments 655 00:21:20,515 --> 00:21:23,250 and rock underneath. 656 00:21:23,284 --> 00:21:24,451 >> Eventually, it 657 00:21:24,519 --> 00:21:25,819 cut down a channel into the 658 00:21:25,887 --> 00:21:26,887 mountain and it eventually 659 00:21:26,921 --> 00:21:28,088 excavated right through the 660 00:21:28,156 --> 00:21:31,258 mountain. 661 00:21:31,292 --> 00:21:33,827 >> But this is just a theory. 662 00:21:33,895 --> 00:21:35,695 Now geologists needed to find 663 00:21:35,730 --> 00:21:38,165 proof on the ground. 664 00:21:38,266 --> 00:21:39,966 The search is on for the rock 665 00:21:40,001 --> 00:21:41,501 yhat eroded from the early 666 00:21:41,536 --> 00:21:44,438 Rockies. 667 00:21:44,539 --> 00:21:45,806 The investigation moves to a 668 00:21:45,907 --> 00:21:47,507 series of thousand-foot-tall 669 00:21:47,542 --> 00:21:49,643 hills in the Powder River basin 670 00:21:49,710 --> 00:21:53,346 in Wyoming. 671 00:21:53,448 --> 00:21:55,882 Known as the Pumpkin Buttes, 672 00:21:55,983 --> 00:21:58,084 they stand tall in an otherwise 673 00:21:58,152 --> 00:22:02,255 wide, empty landscape. 674 00:22:02,356 --> 00:22:03,723 Hidden behind the horizon are 675 00:22:03,791 --> 00:22:05,525 the Bighorn Mountains, the 676 00:22:05,626 --> 00:22:09,362 nearest range of the Rockies. 677 00:22:09,430 --> 00:22:10,697 These hills are not formed from 678 00:22:10,731 --> 00:22:13,066 solid rock but a collection of 679 00:22:13,167 --> 00:22:14,334 rubble. 680 00:22:19,040 --> 00:22:20,207 >> This rock, which 681 00:22:20,241 --> 00:22:21,374 we find all over the top of 682 00:22:21,409 --> 00:22:23,210 Pumpkin Buttes in wyoming, is 683 00:22:23,311 --> 00:22:25,278 granite. The closest granitee 684 00:22:25,379 --> 00:22:27,080 find to this area is the Bighorn 685 00:22:27,114 --> 00:22:28,181 Mountains, nearly a 686 00:22:28,282 --> 00:22:31,818 hundred miles to the west. 687 00:22:31,919 --> 00:22:32,986 >> The round shape of the 688 00:22:33,020 --> 00:22:34,721 granite rocks is further proof 689 00:22:34,822 --> 00:22:36,990 that they traveled from afar. 690 00:22:37,091 --> 00:22:39,059 Tumbling downhill in rivers and 691 00:22:39,093 --> 00:22:41,194 kandslides rounded them on 692 00:22:41,262 --> 00:22:42,696 their journey over millions of 693 00:22:42,730 --> 00:22:45,265 years. 694 00:22:45,366 --> 00:22:47,467 This was a crucial step in the 695 00:22:47,535 --> 00:22:49,002 investigation tracing the 696 00:22:49,070 --> 00:22:50,437 missing rock from the early 697 00:22:50,471 --> 00:22:52,639 Rockies. 698 00:22:52,707 --> 00:22:55,709 Rock and cobbles eroded down 699 00:22:55,743 --> 00:22:57,711 from the Bighorn Mountains and 700 00:22:57,745 --> 00:22:59,446 filled up the basin to at least 701 00:22:59,547 --> 00:23:02,015 1,000 feet, the height of the 702 00:23:02,083 --> 00:23:03,283 Pumpkin Buttes. 703 00:23:03,351 --> 00:23:04,284 >> The Pumpkin Buttes 704 00:23:04,352 --> 00:23:06,419 are unique because this used to 705 00:23:06,454 --> 00:23:09,289 be the actual surface level of 706 00:23:09,357 --> 00:23:11,157 the basin itself. 707 00:23:11,192 --> 00:23:13,560 The rest has been eroded away, 708 00:23:13,628 --> 00:23:15,262 a thousand feet of sediment, to 709 00:23:15,363 --> 00:23:18,999 the basin that we see now. 710 00:23:19,100 --> 00:23:20,367 >> But the rubble found here is 711 00:23:20,468 --> 00:23:22,102 nowhere near enough to have 712 00:23:22,169 --> 00:23:26,106 covered the Owl Creek Mountains. 713 00:23:26,173 --> 00:23:27,807 Mclaughlin traveled to Darton's 714 00:23:27,842 --> 00:23:30,076 Peak, 100 miles west in the 715 00:23:30,144 --> 00:23:32,512 Bighorn Mountains. 716 00:23:32,547 --> 00:23:35,181 On a cliff 9,000 feet high, he 717 00:23:35,283 --> 00:23:37,350 finds granitic cobbles that are 718 00:23:37,451 --> 00:23:39,352 strikingly similar to the ones 719 00:23:39,420 --> 00:23:41,254 on the Pumpkin Buttes. 720 00:23:41,355 --> 00:23:43,456 They, too, are from the core of 721 00:23:43,558 --> 00:23:46,960 the Rocky Mountains. 722 00:23:46,994 --> 00:23:47,994 >> The core of the 723 00:23:48,095 --> 00:23:49,095 Rocky Mountains are made 724 00:23:49,163 --> 00:23:50,096 extensively of granite, much 725 00:23:50,164 --> 00:23:51,698 like what you see here. 726 00:23:51,732 --> 00:23:54,000 These are from the Bighorns 727 00:23:54,068 --> 00:23:55,235 that have been transported 728 00:23:55,269 --> 00:23:57,370 down, rolled, and smoothed along 729 00:23:57,438 --> 00:23:58,338 their way to create these 730 00:23:58,372 --> 00:24:02,642 smaller boulders and cobbles. 731 00:24:02,710 --> 00:24:04,277 >> This is strong evidence that 732 00:24:04,345 --> 00:24:05,512 cobbles eroding from the 733 00:24:05,546 --> 00:24:07,347 Rockies filled in the basins 734 00:24:07,381 --> 00:24:09,349 and valleys to at least 9,000 735 00:24:09,417 --> 00:24:11,618 feet, slowly burying the 736 00:24:11,719 --> 00:24:13,153 Mountains under their own 737 00:24:13,220 --> 00:24:14,788 debris. 738 00:24:14,855 --> 00:24:16,222 Where once the mighty Rockies 739 00:24:16,324 --> 00:24:18,758 stood, there was now a gray, 740 00:24:18,859 --> 00:24:20,760 barren plain with only the 741 00:24:20,861 --> 00:24:22,562 peaks of the old mountains 742 00:24:22,597 --> 00:24:27,467 piercing the surface. 743 00:24:27,501 --> 00:24:28,935 The same process has happened 744 00:24:28,970 --> 00:24:31,671 in other mountain chains, too. 745 00:24:31,772 --> 00:24:32,772 There is evidence that the 746 00:24:32,840 --> 00:24:34,774 European Alps were also cut in 747 00:24:34,875 --> 00:24:38,311 half by erosion. 748 00:24:38,379 --> 00:24:40,146 At their base, scientists found 749 00:24:40,214 --> 00:24:42,048 hills formed out of millions of 750 00:24:42,149 --> 00:24:44,150 tons of rock that had cascaded 751 00:24:44,218 --> 00:24:49,022 down and reduced their height. 752 00:24:49,056 --> 00:24:50,924 But the story of the eroding 753 00:24:50,958 --> 00:24:54,761 Rockies wasn't over yet. 754 00:24:54,829 --> 00:24:56,129 After erosion turned the 755 00:24:56,197 --> 00:24:57,931 landscape into a gray cobble 756 00:24:57,965 --> 00:24:59,833 field, another disruption 757 00:24:59,867 --> 00:25:01,568 happened. 758 00:25:01,602 --> 00:25:03,036 Evidence for this is a layer 759 00:25:03,137 --> 00:25:07,140 covering the top of the cobbles. 760 00:25:07,208 --> 00:25:08,208 >> It's very light. 761 00:25:08,275 --> 00:25:09,275 It's very fine-grained. 762 00:25:09,310 --> 00:25:10,677 It's actually a volcanic ash. 763 00:25:10,778 --> 00:25:11,511 As you can see, it's made of 764 00:25:11,579 --> 00:25:12,746 very, very fine-grained 765 00:25:12,780 --> 00:25:14,214 sediments compared to this 766 00:25:14,281 --> 00:25:16,383 boulder conglomerate, which is 767 00:25:16,417 --> 00:25:18,918 made up of big hunks of rock. 768 00:25:18,953 --> 00:25:20,387 It sits directly on top of this 769 00:25:20,454 --> 00:25:21,655 unit, and it was laid 770 00:25:21,689 --> 00:25:24,157 horizontally from mostly ash 771 00:25:24,191 --> 00:25:27,360 fall. 772 00:25:27,461 --> 00:25:28,928 >> This fine-grained ash 773 00:25:28,996 --> 00:25:31,064 suggests huge volcanic eruptions 774 00:25:31,098 --> 00:25:34,067 nearby. They spewed out thick 775 00:25:34,101 --> 00:25:36,336 clouds of hot air, ash, and 776 00:25:36,370 --> 00:25:38,338 volcanic rock, which settled on 777 00:25:38,372 --> 00:25:42,509 the ground. Radiocarbon dating 778 00:25:42,543 --> 00:25:43,877 the rock revealed that it 779 00:25:43,911 --> 00:25:47,781 happened 25 million years ago. 780 00:25:47,815 --> 00:25:49,449 >> Ash was deposited as it came 781 00:25:49,550 --> 00:25:51,351 out of the sky as plumes. 782 00:25:51,419 --> 00:25:52,619 Most of it came from the west 783 00:25:52,653 --> 00:25:54,988 and was deposited in basins 784 00:25:55,056 --> 00:25:56,823 across Wyoming. 785 00:25:56,891 --> 00:25:58,191 >> After the lower Rockies were 786 00:25:58,259 --> 00:26:00,193 buried by their own rock, 787 00:26:00,261 --> 00:26:02,362 volcanic ash settled on top and 788 00:26:02,430 --> 00:26:03,730 covered the area with a thick 789 00:26:03,831 --> 00:26:08,334 white sheet. 790 00:26:08,369 --> 00:26:09,269 >> At the time of 791 00:26:09,336 --> 00:26:10,704 the deepest basin-fill of this 792 00:26:10,738 --> 00:26:12,272 volcanic material, all you would 793 00:26:12,339 --> 00:26:13,640 see in this area would be the 794 00:26:13,708 --> 00:26:15,442 very tops of the peaks exposed. 795 00:26:15,543 --> 00:26:16,443 The rest would be large, 796 00:26:16,510 --> 00:26:20,413 extensive lateral ash sheets. 797 00:26:20,448 --> 00:26:21,915 >> Erosion and volcanism 798 00:26:21,982 --> 00:26:23,283 completely transformed the 799 00:26:23,350 --> 00:26:26,920 terrain and buried The Rockies. 800 00:26:26,987 --> 00:26:28,321 But then over millions of 801 00:26:28,355 --> 00:26:30,724 years, rivers flushed out the 802 00:26:30,825 --> 00:26:32,726 eroded rock. 803 00:26:32,793 --> 00:26:33,827 Most of it is thought to have 804 00:26:33,894 --> 00:26:35,228 ended up in the Missouri and 805 00:26:35,262 --> 00:26:36,796 Mississippi rivers from where 806 00:26:36,831 --> 00:26:40,366 it was transported into the sea. 807 00:26:40,434 --> 00:26:42,068 What's left are the mountains 808 00:26:42,136 --> 00:26:45,238 we see today. 809 00:26:45,272 --> 00:26:46,706 This also confirmed the theory 810 00:26:46,807 --> 00:26:48,174 geologists had about the 811 00:26:48,275 --> 00:26:51,277 formation of Wind River Canyon. 812 00:26:51,345 --> 00:26:52,979 The incredible amount of infill 813 00:26:53,047 --> 00:26:55,682 buried the Owl Creek Mountain. 814 00:26:55,716 --> 00:26:57,450 Wind River flowed on top and 815 00:26:57,518 --> 00:26:59,486 began carving into the mountain, 816 00:26:59,520 --> 00:27:00,954 creating the canyon we see 817 00:27:01,055 --> 00:27:06,593 today. 818 00:27:06,694 --> 00:27:08,061 The investigation into what 819 00:27:08,129 --> 00:27:09,395 happened to the early Rocky 820 00:27:09,497 --> 00:27:11,231 Mountains reveals two major 821 00:27:11,298 --> 00:27:13,399 clues. 822 00:27:13,501 --> 00:27:14,768 Granite found on the Pumpkin 823 00:27:14,835 --> 00:27:16,136 Buttes is evidence that the 824 00:27:16,237 --> 00:27:17,871 early Rockies dumped their 825 00:27:17,938 --> 00:27:21,508 eroded rock into the basins. 826 00:27:21,575 --> 00:27:22,942 Wind River Canyon cutting 827 00:27:23,043 --> 00:27:24,577 straight through the Owl Creek 828 00:27:24,678 --> 00:27:26,146 Mountains is evidence that the 829 00:27:26,213 --> 00:27:27,580 Rockies were buried by their 830 00:27:27,681 --> 00:27:30,784 own debris. 831 00:27:30,851 --> 00:27:32,752 The once mighty Rockies had now 832 00:27:32,853 --> 00:27:34,654 been cut down to nearly half 833 00:27:34,688 --> 00:27:36,689 their original size, 834 00:27:36,757 --> 00:27:39,926 but the story was far from over. 835 00:27:39,960 --> 00:27:40,927 Before they became the 836 00:27:40,961 --> 00:27:42,829 Mountains we know today, they 837 00:27:42,863 --> 00:27:44,364 would have to endure an even 838 00:27:44,465 --> 00:27:45,064 greater assault. 839 00:27:52,803 --> 00:27:54,337 70 million years ago, a great 840 00:27:54,404 --> 00:27:56,706 inland sea disappeared and the 841 00:27:56,807 --> 00:27:58,608 Rocky Mountains emerged from 842 00:27:58,709 --> 00:28:00,810 yhe sea floor. 843 00:28:00,911 --> 00:28:02,245 60 million years ago, they 844 00:28:02,312 --> 00:28:04,080 reached their peak height-- 845 00:28:04,147 --> 00:28:07,049 twice what it is today. 846 00:28:07,084 --> 00:28:09,151 Then for millions of years, the 847 00:28:09,253 --> 00:28:10,953 Rockies slowly eroded away to 848 00:28:10,988 --> 00:28:12,888 half their original height 849 00:28:12,990 --> 00:28:14,957 until 3 million years ago 850 00:28:14,992 --> 00:28:16,492 another dramatic chapter in 851 00:28:16,526 --> 00:28:18,427 their story began that would 852 00:28:18,528 --> 00:28:19,629 transform them into the 853 00:28:19,696 --> 00:28:21,964 Mountains we know today. 854 00:28:29,406 --> 00:28:30,873 Geologist and photographer Bob 855 00:28:30,907 --> 00:28:33,175 Anderson takes to the air. 856 00:28:33,243 --> 00:28:34,677 He is looking for clues that 857 00:28:34,711 --> 00:28:36,178 will tell him how the mountains 858 00:28:36,246 --> 00:28:39,448 have evolved. 859 00:28:39,516 --> 00:28:40,950 First, he flies over Boulder 860 00:28:40,984 --> 00:28:45,421 Canyon in the Colorado Rockies. 861 00:28:45,489 --> 00:28:46,889 It is an area that has remained 862 00:28:46,990 --> 00:28:49,225 almost unchanged over millions 863 00:28:49,259 --> 00:28:51,060 of years. 864 00:28:51,094 --> 00:28:52,061 >> So, this is Boulder 865 00:28:52,129 --> 00:28:53,396 Canyon we're flying up right 866 00:28:53,397 --> 00:28:56,399 now and you can see how the 867 00:28:56,433 --> 00:28:59,402 river has incised maybe a few 868 00:28:59,403 --> 00:29:00,970 hundred feet down into 869 00:29:01,038 --> 00:29:02,972 otherwise relatively rolling 870 00:29:03,040 --> 00:29:08,077 terrain. 871 00:29:08,145 --> 00:29:09,078 >> The mountain peaks that 872 00:29:09,146 --> 00:29:10,346 existed on the young Rocky 873 00:29:10,414 --> 00:29:12,315 Mountains were rounded off as 874 00:29:12,349 --> 00:29:14,350 rivers and streams eroded the 875 00:29:14,418 --> 00:29:17,787 rock. 876 00:29:17,888 --> 00:29:19,322 >> It's this rolling terrain 877 00:29:19,389 --> 00:29:22,124 that the landscape looked like 878 00:29:22,159 --> 00:29:23,326 in the aftermath of 879 00:29:23,393 --> 00:29:24,694 the mountain-building event that 880 00:29:24,795 --> 00:29:26,228 ended about 50 million years 881 00:29:26,330 --> 00:29:30,066 ago. 882 00:29:30,133 --> 00:29:31,701 >> But as Anderson climbs higher 883 00:29:31,802 --> 00:29:33,069 to Longs Peaks in the Rocky 884 00:29:33,136 --> 00:29:34,970 Mountain National Park, the 885 00:29:35,038 --> 00:29:37,940 terrain changes. 886 00:29:37,974 --> 00:29:39,342 Instead of rolling hills, there 887 00:29:39,409 --> 00:29:40,776 are rugged mountains with 888 00:29:40,844 --> 00:29:43,212 steep, jagged cliffs. 889 00:29:43,246 --> 00:29:44,413 It's evidence that another 890 00:29:44,481 --> 00:29:47,983 force has been at work. 891 00:29:48,051 --> 00:29:49,585 The most famous of these cliffs 892 00:29:49,619 --> 00:29:51,687 is "the Diamond". 893 00:29:51,788 --> 00:29:53,255 Named for its shape, it's a 894 00:29:53,323 --> 00:29:55,591 vertical wall with a sheer 900 895 00:29:55,692 --> 00:29:57,793 foot drop. 896 00:29:57,861 --> 00:29:59,962 The summit, about 45,000 square 897 00:30:00,030 --> 00:30:02,231 feet, is the same size as a 898 00:30:02,299 --> 00:30:04,934 football field. 899 00:30:04,968 --> 00:30:05,701 >> Well, we're flying 900 00:30:05,769 --> 00:30:08,337 beside Longs Peak, one of the 901 00:30:08,405 --> 00:30:09,972 biggest climbing 902 00:30:10,040 --> 00:30:11,941 challenges in The Rockies. 903 00:30:11,975 --> 00:30:13,509 For a century, it's been a 904 00:30:13,610 --> 00:30:15,511 climbing mecca. 905 00:30:15,612 --> 00:30:17,913 It's a gorgeous intact piece 906 00:30:17,948 --> 00:30:20,483 of rock. 907 00:30:20,550 --> 00:30:22,485 >> This awesome wall is the most 908 00:30:22,552 --> 00:30:24,086 difficult climb in the whole of 909 00:30:24,121 --> 00:30:26,021 the Rockies, and since it was 910 00:30:26,089 --> 00:30:27,490 officially opened to climbers 911 00:30:27,557 --> 00:30:30,259 in 1960 has claimed over 50 912 00:30:30,293 --> 00:30:35,464 lives. 913 00:30:35,499 --> 00:30:36,632 Back on the ground, 914 00:30:36,666 --> 00:30:37,833 Anderson is looking for 915 00:30:37,934 --> 00:30:39,301 evidence that will reveal the 916 00:30:39,369 --> 00:30:40,936 processes that shaped the 917 00:30:41,004 --> 00:30:43,472 jagged peaks. 918 00:30:43,573 --> 00:30:45,741 On a hillside, he finds 919 00:30:45,809 --> 00:30:47,743 mysterious large boulders 920 00:30:47,844 --> 00:30:48,911 scattered across the valley 921 00:30:48,979 --> 00:30:50,379 floor. 922 00:30:50,447 --> 00:30:53,015 [tapping rock] 923 00:30:53,116 --> 00:30:54,550 A closer look uncovers some 924 00:30:54,651 --> 00:30:58,754 secrets about their origin. 925 00:30:58,822 --> 00:30:59,822 >> I'm standing in 926 00:30:59,856 --> 00:31:01,190 front of a rounded boulder that 927 00:31:01,291 --> 00:31:03,392 itself is sitting on a smooth 928 00:31:03,460 --> 00:31:06,462 bedrock outcrop. 929 00:31:06,530 --> 00:31:07,830 Both the boulder and the 930 00:31:07,898 --> 00:31:09,899 outcrop are covered in lichen 931 00:31:09,933 --> 00:31:12,301 here of green to black to 932 00:31:12,369 --> 00:31:15,104 gray colors, and therefore I had 933 00:31:15,205 --> 00:31:16,705 to whack off a piece of the 934 00:31:16,740 --> 00:31:18,641 rock in order to see inside the 935 00:31:18,742 --> 00:31:19,708 rock. 936 00:31:19,743 --> 00:31:20,810 And indeed it is different. 937 00:31:20,844 --> 00:31:22,278 The minerals that I see and the 938 00:31:22,345 --> 00:31:23,913 texture of the rock is 939 00:31:24,014 --> 00:31:25,347 different from the underlying 940 00:31:25,382 --> 00:31:27,016 rock. And therefore the rock is 941 00:31:27,083 --> 00:31:31,554 foreign to this particular site. 942 00:31:31,655 --> 00:31:33,088 >> Anderson searches the ground 943 00:31:33,156 --> 00:31:35,024 for more clues as to how this 944 00:31:35,091 --> 00:31:37,726 massive boulder got here. 945 00:31:37,828 --> 00:31:39,628 Nearby, he finds a smooth 946 00:31:39,729 --> 00:31:41,931 surface with very fine scratch 947 00:31:41,998 --> 00:31:44,633 marks. 948 00:31:44,734 --> 00:31:45,835 >> I'm sitting on a 949 00:31:45,902 --> 00:31:47,470 polished surface. This little 950 00:31:47,537 --> 00:31:49,738 piece right here is smooth to 951 00:31:49,840 --> 00:31:51,674 the touch. And if I look at it 952 00:31:51,741 --> 00:31:53,442 in a certain way that the light 953 00:31:53,477 --> 00:31:55,110 glints off of it just right, I 954 00:31:55,178 --> 00:31:56,178 can see that there are 955 00:31:56,246 --> 00:31:57,746 scratches running in this 956 00:31:57,814 --> 00:31:59,715 direction across the surface. 957 00:31:59,816 --> 00:32:01,083 >> The only force that could 958 00:32:01,184 --> 00:32:02,651 have produced these fine, 959 00:32:02,719 --> 00:32:04,720 parallel scratches on the rock 960 00:32:04,821 --> 00:32:09,358 is ice, and lots of it. 961 00:32:09,426 --> 00:32:11,093 It's a clue that a massive 962 00:32:11,194 --> 00:32:15,464 glacier once filled this valley. 963 00:32:15,532 --> 00:32:16,465 >> And that tells me 964 00:32:16,533 --> 00:32:17,533 that the glacier came 965 00:32:17,634 --> 00:32:18,901 down-valley, came across this 966 00:32:19,002 --> 00:32:22,037 surface and eroded it. 967 00:32:22,072 --> 00:32:23,439 Each one of these scratches 968 00:32:23,507 --> 00:32:25,207 corresponds to a sand grain 969 00:32:25,242 --> 00:32:27,142 embedded in the sole of the ice 970 00:32:27,244 --> 00:32:28,878 that just like sandpaper 971 00:32:28,945 --> 00:32:30,513 smoothes off the surface. So 972 00:32:30,580 --> 00:32:32,248 zillions of sand grains over 973 00:32:32,315 --> 00:32:34,416 thousands of years will have 974 00:32:34,484 --> 00:32:38,120 eroded this surface smooth. 975 00:32:38,154 --> 00:32:39,588 >> As glaciers flowed down the 976 00:32:39,656 --> 00:32:41,690 valley, they picked up rocks 977 00:32:41,758 --> 00:32:43,692 and grit. 978 00:32:43,760 --> 00:32:45,661 The ice pushed down on these 979 00:32:45,695 --> 00:32:46,962 cutting tools with the weight 980 00:32:47,063 --> 00:32:48,864 of over a thousand fully loaded 981 00:32:48,965 --> 00:32:51,600 garbage trucks. 982 00:32:51,701 --> 00:32:53,402 It left scratch marks all over 983 00:32:53,503 --> 00:32:55,404 the Rockies up to 1,000 feet 984 00:32:55,472 --> 00:32:56,972 high. 985 00:32:57,040 --> 00:32:59,241 This is evidence that a massive 986 00:32:59,309 --> 00:33:01,110 wall of ice covered this part 987 00:33:01,177 --> 00:33:02,811 of The Rockies and shaped the 988 00:33:02,846 --> 00:33:04,914 mountains. 989 00:33:05,015 --> 00:33:06,382 The ice ripped out the rock 990 00:33:06,483 --> 00:33:08,183 from the valley walls and left 991 00:33:08,218 --> 00:33:10,452 behind the jagged cliffs and 992 00:33:10,487 --> 00:33:14,924 rugged edges. 993 00:33:14,991 --> 00:33:15,891 >> For the last few 994 00:33:15,926 --> 00:33:17,092 million years, perhaps 3 995 00:33:17,193 --> 00:33:18,394 million years, glaciers have 996 00:33:18,461 --> 00:33:20,462 come and gone from the Rocky 997 00:33:20,530 --> 00:33:22,197 Mountains. And every time they 998 00:33:22,265 --> 00:33:23,832 come across the landscape, 999 00:33:23,900 --> 00:33:25,200 they're capable of eroding that 1000 00:33:25,302 --> 00:33:27,102 landscape at rates that are 1001 00:33:27,170 --> 00:33:29,638 perhaps fractions of an inch 1002 00:33:29,739 --> 00:33:31,907 per year, meaning that over the 1003 00:33:32,008 --> 00:33:35,277 course of one glacial cycle you 1004 00:33:35,378 --> 00:33:38,547 perhaps erode 10, 20 feet 1005 00:33:38,648 --> 00:33:40,649 of rock. 1006 00:33:40,750 --> 00:33:42,451 >> Ice also created the broad 1007 00:33:42,485 --> 00:33:44,286 Canyons. 1008 00:33:44,387 --> 00:33:46,288 With every ice age, new glaciers 1009 00:33:46,356 --> 00:33:48,257 ground their way down v-shaped 1010 00:33:48,291 --> 00:33:49,825 river valleys and turned them 1011 00:33:49,893 --> 00:33:56,065 into broad u-shaped canyons. 1012 00:33:56,099 --> 00:33:56,932 >> For the glacier, 1013 00:33:57,000 --> 00:33:58,367 the whole valley is its 1014 00:33:58,435 --> 00:34:00,469 channel, so any place where the 1015 00:34:00,570 --> 00:34:02,438 glacier touches the wall it's 1016 00:34:02,472 --> 00:34:04,073 capable of eroding it. 1017 00:34:04,174 --> 00:34:05,874 And therefore the walls 1018 00:34:05,942 --> 00:34:07,309 will be made more vertical on 1019 00:34:07,344 --> 00:34:08,877 the edges and be flattened on 1020 00:34:08,979 --> 00:34:10,613 the base, until it gets 1021 00:34:10,680 --> 00:34:12,881 to now a u-shape which then 1022 00:34:12,949 --> 00:34:15,484 propagates downward. 1023 00:34:15,518 --> 00:34:16,986 >> Ice also explains the 1024 00:34:17,053 --> 00:34:20,623 presence of these boulders. 1025 00:34:20,690 --> 00:34:22,057 They hitchhiked at the bottom 1026 00:34:22,125 --> 00:34:23,792 of a glacier down the frozen 1027 00:34:23,860 --> 00:34:25,761 valley. 1028 00:34:25,795 --> 00:34:27,329 When the last ice age came to 1029 00:34:27,430 --> 00:34:29,331 an end and the glaciers melted 1030 00:34:29,432 --> 00:34:31,433 about 10,000 years ago, the 1031 00:34:31,501 --> 00:34:36,772 boulders were left behind. 1032 00:34:36,806 --> 00:34:38,774 Scientists had found two pieces 1033 00:34:38,842 --> 00:34:39,875 of evidence that were 1034 00:34:39,976 --> 00:34:41,210 responsible for the jagged 1035 00:34:41,244 --> 00:34:43,946 looks of the Rockies today. 1036 00:34:43,980 --> 00:34:45,614 A solitary boulder foreign to 1037 00:34:45,682 --> 00:34:47,149 the area could have only been 1038 00:34:47,217 --> 00:34:50,419 transported here by ice. 1039 00:34:50,520 --> 00:34:52,254 Striations showed scientists 1040 00:34:52,288 --> 00:34:53,889 that a glacier at least 1,000 1041 00:34:53,957 --> 00:34:57,326 feet thick covered the Rockies. 1042 00:34:57,360 --> 00:34:58,794 Ice was responsible for the 1043 00:34:58,862 --> 00:35:00,429 dramatic shape of the Rockies 1044 00:35:00,497 --> 00:35:01,964 today. 1045 00:35:02,032 --> 00:35:04,033 But the mountains keep evolving. 1046 00:35:04,067 --> 00:35:05,668 Recently, scientists discovered 1047 00:35:05,702 --> 00:35:07,603 alarming evidence that they may 1048 00:35:07,704 --> 00:35:10,839 collapse into a deep rift. 1049 00:35:20,028 --> 00:35:21,962 For the last 70 million years, 1050 00:35:22,030 --> 00:35:24,131 compression, erosion and ice 1051 00:35:24,232 --> 00:35:25,299 have sculpted the Rocky 1052 00:35:25,333 --> 00:35:26,600 Mountains to their present 1053 00:35:26,668 --> 00:35:28,402 formation. 1054 00:35:28,503 --> 00:35:29,837 But the geology that created 1055 00:35:29,871 --> 00:35:30,771 this impressive 1056 00:35:30,872 --> 00:35:32,973 Mountain range has also the 1057 00:35:33,041 --> 00:35:35,876 potential to destroy it. 1058 00:35:35,977 --> 00:35:38,412 Over the last 25 million years, 1059 00:35:38,479 --> 00:35:40,047 a gigantic rift has been 1060 00:35:40,114 --> 00:35:41,415 opening up at the southern end 1061 00:35:41,482 --> 00:35:43,951 of the Rocky Mountains. 1062 00:35:44,052 --> 00:35:46,420 It stretches over 160,000 square 1063 00:35:46,487 --> 00:35:48,922 miles and is known as the Rio 1064 00:35:48,957 --> 00:35:51,225 Grande Valley. 1065 00:35:51,292 --> 00:35:52,392 Geologists are eager to 1066 00:35:52,427 --> 00:35:54,061 investigate how this giant 1067 00:35:54,128 --> 00:35:55,696 rifting valley could affect the 1068 00:35:55,763 --> 00:36:00,334 future of the Rockies. 1069 00:36:00,401 --> 00:36:01,702 They find their first lead in 1070 00:36:01,769 --> 00:36:03,837 San Ysidro, New Mexico, north 1071 00:36:03,872 --> 00:36:06,473 of Albuquerque. 1072 00:36:06,507 --> 00:36:08,675 The area is dominated by 1073 00:36:08,776 --> 00:36:11,144 bright, yellow, porous rock 1074 00:36:11,212 --> 00:36:14,214 known as travertines. 1075 00:36:14,315 --> 00:36:16,583 Curiously, geologists think 1076 00:36:16,684 --> 00:36:20,587 this rock forms from water. 1077 00:36:20,588 --> 00:36:23,323 >> This water has some unusual 1078 00:36:23,391 --> 00:36:24,591 characteristics, and that is 1079 00:36:24,692 --> 00:36:26,693 this water's capable of 1080 00:36:26,694 --> 00:36:28,295 precipitating, or depositing, a 1081 00:36:28,329 --> 00:36:30,564 new rock called travertine. It's 1082 00:36:30,598 --> 00:36:32,199 kind of like the scale in your 1083 00:36:32,233 --> 00:36:34,835 teapot. 1084 00:36:34,869 --> 00:36:36,103 >> Travertine rock is 1085 00:36:36,137 --> 00:36:38,238 made out of calcite, the same 1086 00:36:38,306 --> 00:36:39,873 material that builds up lime 1087 00:36:39,941 --> 00:36:44,511 scale. These rocks grow very 1088 00:36:44,579 --> 00:36:47,281 rapidly. Some enlarge by a few 1089 00:36:47,315 --> 00:36:49,149 inches per month. 1090 00:36:49,217 --> 00:36:50,217 >> About a liter of 1091 00:36:50,218 --> 00:36:51,919 the water will be able to drop 1092 00:36:51,953 --> 00:36:54,321 out or precipitate a little 1093 00:36:54,389 --> 00:36:56,189 pile of calcite about as big as 1094 00:36:56,190 --> 00:36:58,592 an aspirin tablet. 1095 00:36:58,660 --> 00:37:00,193 >> Like lime scale building up 1096 00:37:00,228 --> 00:37:01,595 in a hot water kettle, 1097 00:37:01,663 --> 00:37:03,664 travertines form around warm 1098 00:37:03,731 --> 00:37:08,502 springs. Measurements confirm 1099 00:37:08,569 --> 00:37:10,003 that water temperature around 1100 00:37:10,038 --> 00:37:12,005 the travertines is roughly 77 1101 00:37:12,040 --> 00:37:15,309 degrees. 1102 00:37:15,410 --> 00:37:16,743 Besides the ability to build 1103 00:37:16,778 --> 00:37:19,413 rock, this hot water has more 1104 00:37:19,480 --> 00:37:23,317 secrets to tell. 1105 00:37:23,384 --> 00:37:24,484 Laura Crossey and Karl 1106 00:37:24,585 --> 00:37:26,453 Karlstrom have a hunch that the 1107 00:37:26,487 --> 00:37:28,555 water is warmed up by heat from 1108 00:37:28,589 --> 00:37:30,958 the Earth's interior, rising up 1109 00:37:31,025 --> 00:37:34,294 through cracks in the rock. 1110 00:37:34,362 --> 00:37:36,129 They form as the rift valley 1111 00:37:36,230 --> 00:37:38,999 pulls apart. 1112 00:37:39,033 --> 00:37:40,934 Climbing down a cave 25 feet 1113 00:37:41,035 --> 00:37:42,302 below the surface, they are 1114 00:37:42,370 --> 00:37:47,574 hoping to find further evidence. 1115 00:37:47,642 --> 00:37:50,377 The water contains microbes. 1116 00:37:50,478 --> 00:37:51,912 They are microscopically small 1117 00:37:51,946 --> 00:37:53,914 organisms. 1118 00:37:53,948 --> 00:37:55,282 Most of them consist of only 1119 00:37:55,316 --> 00:37:57,584 one cell. 1120 00:37:57,652 --> 00:37:58,952 When scientists analyzed their 1121 00:37:59,020 --> 00:38:00,721 genes in the lab, they found 1122 00:38:00,755 --> 00:38:03,223 something remarkable. 1123 00:38:03,291 --> 00:38:04,358 >> What we found in springs like 1124 00:38:04,392 --> 00:38:06,393 this by doing the dna analysis 1125 00:38:06,461 --> 00:38:07,761 is that the microbes that are 1126 00:38:07,862 --> 00:38:10,197 coming up these faults are much 1127 00:38:10,264 --> 00:38:11,832 more like what we find 1128 00:38:11,933 --> 00:38:13,467 at mid-ocean ridges than like 1129 00:38:13,568 --> 00:38:14,768 the rivers and streams we would 1130 00:38:14,836 --> 00:38:18,105 expect in a continental setting. 1131 00:38:18,172 --> 00:38:19,673 >> Mid-ocean ridges are very 1132 00:38:19,741 --> 00:38:21,375 long mountain chains under the 1133 00:38:21,476 --> 00:38:24,378 sea. Just like the rift valley, 1134 00:38:24,479 --> 00:38:26,313 they also form in geologically 1135 00:38:26,381 --> 00:38:28,482 active areas where lava 1136 00:38:28,549 --> 00:38:30,650 constantly erupts and builds up 1137 00:38:30,718 --> 00:38:32,486 new crust. 1138 00:38:32,553 --> 00:38:34,221 Any living organism surviving 1139 00:38:34,288 --> 00:38:36,023 down there has to be able to 1140 00:38:36,124 --> 00:38:39,459 cope with these hot conditions. 1141 00:38:39,494 --> 00:38:41,028 >> The springs here in the 1142 00:38:41,129 --> 00:38:42,462 mid-ocean ridge settings are 1143 00:38:42,563 --> 00:38:43,730 also characterized by 1144 00:38:43,765 --> 00:38:45,365 the upwelling of deep hot fluids 1145 00:38:45,400 --> 00:38:46,933 from within the Earth, 1146 00:38:47,001 --> 00:38:48,802 indicating that these both are 1147 00:38:48,836 --> 00:38:50,470 connected to that deep tectonic 1148 00:38:50,571 --> 00:38:52,205 setting. 1149 00:38:52,273 --> 00:38:53,473 >> The microbes suggest 1150 00:38:53,541 --> 00:38:55,275 deep tectonic forces are at 1151 00:38:55,309 --> 00:38:58,111 work, but there is even more 1152 00:38:58,179 --> 00:39:00,213 compelling evidence. 1153 00:39:00,281 --> 00:39:01,648 Karlstrom and Crossey find an 1154 00:39:01,749 --> 00:39:04,017 unusually high amount of gas 1155 00:39:04,085 --> 00:39:06,119 bubbling up through the water. 1156 00:39:06,187 --> 00:39:07,387 >> These samples are kind of fun 1157 00:39:07,455 --> 00:39:08,755 because it looks like an empty 1158 00:39:08,823 --> 00:39:10,190 glass bottle, but it started out 1159 00:39:10,291 --> 00:39:12,092 full of water. And then we 1160 00:39:12,193 --> 00:39:13,393 filled up--turned it upside- 1161 00:39:13,461 --> 00:39:14,761 down in the water, and the gas 1162 00:39:14,829 --> 00:39:15,929 displaced the water until it's 1163 00:39:16,030 --> 00:39:17,464 full of gas. 1164 00:39:17,565 --> 00:39:18,999 >> A lab analysis identifies the 1165 00:39:19,033 --> 00:39:20,834 gas as helium. 1166 00:39:20,902 --> 00:39:22,569 This is the conclusive evidence 1167 00:39:22,637 --> 00:39:24,271 that deep tectonic forces are 1168 00:39:24,372 --> 00:39:26,073 at work here. 1169 00:39:26,107 --> 00:39:28,742 >> The helium is the most 1170 00:39:28,843 --> 00:39:30,010 interesting gas for us. It's 1171 00:39:30,078 --> 00:39:31,545 the smoking gun of evidence 1172 00:39:31,646 --> 00:39:33,647 for where these fluids 1173 00:39:33,748 --> 00:39:34,848 have come from. 1174 00:39:34,916 --> 00:39:36,450 There's two forms of helium, but 1175 00:39:36,484 --> 00:39:38,819 yt's the helium 3 that we're 1176 00:39:38,920 --> 00:39:40,287 most interested in, and that 1177 00:39:40,388 --> 00:39:42,556 form of helium is only derived 1178 00:39:42,657 --> 00:39:45,192 from the Earth's mantle. 1179 00:39:45,293 --> 00:39:46,359 >> The mantle is a part of the 1180 00:39:46,461 --> 00:39:48,361 Earth's interior 30 miles below 1181 00:39:48,463 --> 00:39:49,663 the surface. 1182 00:39:49,730 --> 00:39:51,064 It is made up of hot, molten 1183 00:39:51,099 --> 00:39:53,300 rock. 1184 00:39:53,367 --> 00:39:55,569 In areas where magma moves up, 1185 00:39:55,636 --> 00:39:57,571 pressure on top of it decreases 1186 00:39:57,638 --> 00:39:59,005 and gases such as helium are 1187 00:39:59,107 --> 00:40:01,374 released. 1188 00:40:01,476 --> 00:40:02,843 They find their way through 1189 00:40:02,910 --> 00:40:04,444 faults and cracks until they 1190 00:40:04,479 --> 00:40:07,914 reach the surface. 1191 00:40:07,982 --> 00:40:10,083 So, helium gas is conclusive 1192 00:40:10,184 --> 00:40:11,918 proof that geological forces 1193 00:40:12,019 --> 00:40:13,186 deep under the Earth are 1194 00:40:13,287 --> 00:40:15,288 building up, 1195 00:40:15,356 --> 00:40:16,656 and the effect it will have on 1196 00:40:16,724 --> 00:40:19,826 the Rockies is devastating. 1197 00:40:19,927 --> 00:40:21,094 >> The Rio Grande rift 1198 00:40:21,162 --> 00:40:22,529 is an area that's 1199 00:40:22,563 --> 00:40:24,464 tectonically active 1200 00:40:24,532 --> 00:40:25,532 in a different way than you 1201 00:40:25,566 --> 00:40:27,200 think of building of mountains. 1202 00:40:27,268 --> 00:40:29,903 This area is the next stage 1203 00:40:29,971 --> 00:40:31,471 in the life sometimes of a 1204 00:40:31,539 --> 00:40:33,106 mountain belt where it starts to 1205 00:40:33,174 --> 00:40:35,809 collapse, it starts to extend. 1206 00:40:35,910 --> 00:40:37,344 >> As hot magma 1207 00:40:37,378 --> 00:40:38,979 surges upwards from 30 miles 1208 00:40:39,013 --> 00:40:40,814 below the surface, it forces the 1209 00:40:40,882 --> 00:40:44,184 area on top to spread. 1210 00:40:44,252 --> 00:40:46,520 The surface stretches and thins 1211 00:40:46,554 --> 00:40:49,789 and opens up a deep chasm. 1212 00:40:49,824 --> 00:40:51,057 As the rift opens, the 1213 00:40:51,092 --> 00:40:53,260 mountains to each side crumble 1214 00:40:53,327 --> 00:40:57,464 into the valley. 1215 00:40:57,532 --> 00:40:58,532 >> You can think of a piece 1216 00:40:58,633 --> 00:41:00,634 of taffy that's being stretched, 1217 00:41:00,701 --> 00:41:02,235 and it might break on the top. 1218 00:41:02,270 --> 00:41:04,538 And those breaks would lower 1219 00:41:04,605 --> 00:41:06,239 pieces of the--they would drop 1220 00:41:06,274 --> 00:41:08,375 down. And then once you have 1221 00:41:08,442 --> 00:41:10,644 what's called a fault valley, 1222 00:41:10,711 --> 00:41:13,146 then the sediments wash in from 1223 00:41:13,181 --> 00:41:14,347 the high mountains. It's an 1224 00:41:14,448 --> 00:41:16,283 immense structure. It's 1225 00:41:16,350 --> 00:41:18,552 about 6 miles deep. It's about 1226 00:41:18,619 --> 00:41:20,086 as deep as Mount Everest is 1227 00:41:20,154 --> 00:41:22,189 high. But when you drive 1228 00:41:22,256 --> 00:41:23,623 across it or you look at it 1229 00:41:23,691 --> 00:41:26,193 from any vantage point, 1230 00:41:26,260 --> 00:41:28,962 you don't see that entire depth 1231 00:41:28,996 --> 00:41:30,163 because it's all been filled 1232 00:41:30,231 --> 00:41:31,164 with sand and gravel 1233 00:41:31,232 --> 00:41:33,166 progressively as the extension 1234 00:41:33,234 --> 00:41:34,534 took place. 1235 00:41:34,635 --> 00:41:36,269 >> Today, the Rio Grande rift 1236 00:41:36,370 --> 00:41:39,072 stretches over 160,000 square 1237 00:41:39,173 --> 00:41:41,374 miles from Mexico in the south 1238 00:41:41,442 --> 00:41:42,809 where it's broadest, to 1239 00:41:42,910 --> 00:41:44,711 Colorado in the north where 1240 00:41:44,812 --> 00:41:46,980 it's only just begun to open up. 1241 00:41:47,048 --> 00:41:48,448 >> This rift is propagating 1242 00:41:48,516 --> 00:41:50,617 northwards into the higher 1243 00:41:50,718 --> 00:41:51,718 Colorado Rockies. 1244 00:41:51,786 --> 00:41:52,686 What's gonna happen to 1245 00:41:52,720 --> 00:41:54,054 Colorado, those mountains will 1246 00:41:54,088 --> 00:41:57,157 probably collapse by rifting, 1247 00:41:57,258 --> 00:41:58,992 as the rift propagates, zippers 1248 00:41:59,093 --> 00:42:00,327 northward. And you can 1249 00:42:00,428 --> 00:42:02,429 visualize that what's 1250 00:42:02,463 --> 00:42:05,165 now in Colorado is more similar 1251 00:42:05,266 --> 00:42:06,800 to what was in New Mexico 1252 00:42:06,867 --> 00:42:08,068 before the Rio Grande rift 1253 00:42:08,135 --> 00:42:09,803 opened and before the mountains 1254 00:42:09,904 --> 00:42:13,173 collapsed. 1255 00:42:13,241 --> 00:42:14,274 >> Looking ahead in the distant 1256 00:42:14,342 --> 00:42:15,408 future, there could be 1257 00:42:15,443 --> 00:42:17,277 challenging times. 1258 00:42:17,345 --> 00:42:19,179 The tectonic forces that created 1259 00:42:19,247 --> 00:42:20,614 the Rockies could eventually 1260 00:42:20,648 --> 00:42:22,983 lead to their destruction. 1261 00:42:23,050 --> 00:42:23,883 >> When we think 1262 00:42:23,985 --> 00:42:24,985 about the great continental 1263 00:42:25,086 --> 00:42:26,953 rifts of East African and Rio 1264 00:42:26,988 --> 00:42:28,088 Grande rift, the question 1265 00:42:28,155 --> 00:42:30,790 arises: Is the continent gonna 1266 00:42:30,858 --> 00:42:32,158 split apart here? If this 1267 00:42:32,226 --> 00:42:33,727 rifting carries on, are we gonna 1268 00:42:33,794 --> 00:42:36,529 have beachfront property right 1269 00:42:36,631 --> 00:42:38,865 here in New Mexico? And the 1270 00:42:38,899 --> 00:42:40,233 realtors are very interested in 1271 00:42:40,268 --> 00:42:42,802 this, but so are the geologists. 1272 00:42:42,870 --> 00:42:44,037 >> The formation of the Rocky 1273 00:42:44,071 --> 00:42:48,675 Mountains is a remarkable story. 1274 00:42:48,709 --> 00:42:50,510 70 million years ago. The death 1275 00:42:50,544 --> 00:42:52,078 ff ancient ammonites marked the 1276 00:42:52,179 --> 00:42:53,713 rise of the Rocky Mountains 1277 00:42:53,814 --> 00:42:57,517 from the retreating inland sea. 1278 00:42:57,618 --> 00:42:59,419 60 million years ago, leaves 1279 00:42:59,520 --> 00:43:01,087 with jagged margins grew on the 1280 00:43:01,155 --> 00:43:02,522 Mountains that were twice as 1281 00:43:02,590 --> 00:43:05,258 high as today. 1282 00:43:05,326 --> 00:43:07,527 10,000 years ago, a solitary 1283 00:43:07,628 --> 00:43:09,162 boulder marked the retreat of 1284 00:43:09,263 --> 00:43:11,064 the last glacier, that sculpted 1285 00:43:11,132 --> 00:43:12,799 the Rockies. 1286 00:43:12,900 --> 00:43:14,267 And helium gas in the Rio 1287 00:43:14,335 --> 00:43:16,503 Grande Valley today is a clue 1288 00:43:16,537 --> 00:43:17,871 that the area deep under the 1289 00:43:17,972 --> 00:43:23,343 surface is active again. 1290 00:43:23,444 --> 00:43:25,045 If rifting continues and the 1291 00:43:25,079 --> 00:43:27,047 Rio Grande Valley widens, the 1292 00:43:27,081 --> 00:43:28,581 area of the Rocky Mountains 1293 00:43:28,616 --> 00:43:31,618 could one day rip apart. 1294 00:43:31,719 --> 00:43:34,254 A new sea would move in, like 1295 00:43:34,322 --> 00:43:35,989 the vast inland sea that 1296 00:43:36,057 --> 00:43:37,957 covered the area 70 million 1297 00:43:37,992 --> 00:43:40,427 years ago. 1298 00:43:40,428 --> 00:43:42,028 The Rocky Mountains, the great 1299 00:43:42,063 --> 00:43:44,431 backbone of North America would 1300 00:43:44,498 --> 00:43:46,966 slowly disappear, and the 1301 00:43:47,034 --> 00:43:50,236 continent would once more split. 1302 00:43:50,304 --> 00:43:52,872 - Living proof that the Earth 1303 00:43:52,907 --> 00:43:54,507 is never at rest. 1304 00:43:54,508 --> 00:44:00,508 -- Sync, corrected by elderman -- -- for MY-SUBS.com ---