1 00:00:01,334 --> 00:00:04,333 North America, the land that we love. 2 00:00:04,334 --> 00:00:07,334 It looks pretty familiar, don't you think? 3 00:00:12,334 --> 00:00:13,334 Well, think again! 4 00:00:19,334 --> 00:00:23,333 The ground we walk on is full of surprises 5 00:00:23,334 --> 00:00:24,333 if you know where to look. 6 00:00:24,334 --> 00:00:26,333 As a geologist, 7 00:00:26,334 --> 00:00:29,333 the Grand Canyon is perhaps the best place in the world. 8 00:00:29,334 --> 00:00:31,333 Every single one of these layers tells its own story 9 00:00:31,334 --> 00:00:33,333 about what North America was like 10 00:00:33,334 --> 00:00:36,333 when that layer was deposited. 11 00:00:36,334 --> 00:00:38,014 Are you ready for a little time travelling? 12 00:00:38,334 --> 00:00:40,333 I'm Kirk Johnson, 13 00:00:40,334 --> 00:00:42,333 the director of the Smithsonian 14 00:00:42,334 --> 00:00:44,334 National Museum of Natural History, 15 00:00:45,334 --> 00:00:49,333 and I'm taking off on the field trip of a lifetime. 16 00:00:49,334 --> 00:00:51,333 Wow, look at that rock right there. 17 00:00:51,334 --> 00:00:53,333 That is crazy! 18 00:00:53,334 --> 00:00:55,333 To find out how did our amazing continent 19 00:00:55,334 --> 00:00:57,333 get to be the way it is? 20 00:00:57,334 --> 00:00:59,333 Underneath Lake Superior, 21 00:00:59,334 --> 00:01:00,333 that's about 30 miles of volcanic rock. 22 00:01:00,334 --> 00:01:03,334 30 miles of volcanic rock? 23 00:01:05,334 --> 00:01:08,333 How did the landscape shape the creatures 24 00:01:08,334 --> 00:01:09,333 who lived and died here? 25 00:01:09,334 --> 00:01:11,333 14-foot-long fish in Kansas? 26 00:01:11,334 --> 00:01:12,454 That's what I'm telling you! 27 00:01:14,334 --> 00:01:17,333 And how did we turn the rocks of our homeland... 28 00:01:17,334 --> 00:01:18,333 Oh, man! 29 00:01:18,334 --> 00:01:19,333 ...into riches? 30 00:01:19,334 --> 00:01:20,334 This thing is phenomenal. 31 00:01:21,334 --> 00:01:25,333 In this episode, we hunt down the clues 32 00:01:25,334 --> 00:01:26,333 to our continent's epic past. 33 00:01:26,334 --> 00:01:29,333 You can see new land being formed 34 00:01:29,334 --> 00:01:30,333 right in front of your eyes. 35 00:01:30,334 --> 00:01:33,333 Why does this golf course hold the secret 36 00:01:33,334 --> 00:01:35,334 to the rise and fall of the Rockies? 37 00:01:37,334 --> 00:01:40,333 What forces nearly cracked North America in half? 38 00:01:40,334 --> 00:01:44,333 And is it possible that the New York City skyline... 39 00:01:44,334 --> 00:01:45,333 I've always wanted to do this. 40 00:01:45,334 --> 00:01:49,333 ...was once dominated not by skyscrapers, 41 00:01:49,334 --> 00:01:50,374 but by towering mountains? 42 00:01:55,334 --> 00:01:59,333 We're uncovering secrets hiding in our own backyard. 43 00:01:59,334 --> 00:02:00,333 Peel it back. 44 00:02:00,334 --> 00:02:03,333 Whoa, that is unbelievable! 45 00:02:03,334 --> 00:02:09,334 "Making North America: Origins," right now on NOVA. 46 00:02:29,503 --> 00:02:32,503 North America, our continent. 47 00:02:35,503 --> 00:02:37,503 Filled with all these spectacular landscapes. 48 00:02:45,466 --> 00:02:49,465 They look like they've been here forever, 49 00:02:49,466 --> 00:02:51,466 but they are anything but permanent. 50 00:02:55,466 --> 00:03:00,465 The truth is, our continent has had its ups and downs... 51 00:03:00,466 --> 00:03:01,466 Literally! 52 00:03:04,466 --> 00:03:10,465 It's an epic tale of creation and destruction 53 00:03:10,466 --> 00:03:13,465 playing out over thousands, millions, 54 00:03:13,466 --> 00:03:16,466 even billions of years. 55 00:03:18,466 --> 00:03:19,465 Wow. 56 00:03:19,466 --> 00:03:20,465 We're going to trace this story 57 00:03:20,466 --> 00:03:24,465 back to the very beginning, 58 00:03:24,466 --> 00:03:26,466 to the origins of North America. 59 00:03:44,466 --> 00:03:48,466 Our journey starts here in the American Southwest. 60 00:03:57,466 --> 00:04:00,465 This place is a paradise for geologists 61 00:04:00,466 --> 00:04:02,466 and one of our national treasures. 62 00:04:04,466 --> 00:04:08,466 It is, of course, the Grand Canyon. 63 00:04:11,466 --> 00:04:15,465 That is a big hole! 64 00:04:15,466 --> 00:04:16,506 And it gets me every time. 65 00:04:21,466 --> 00:04:24,466 Wow, this is absolutely awesome! 66 00:04:26,466 --> 00:04:29,465 The landscape is breathtaking, and so much more. 67 00:04:29,466 --> 00:04:32,465 As a geologist, the Grand Canyon 68 00:04:32,466 --> 00:04:34,465 is perhaps the best place in the world. 69 00:04:34,466 --> 00:04:36,465 It's this incredible 300-mile-long slice 70 00:04:36,466 --> 00:04:38,465 through the earth, 71 00:04:38,466 --> 00:04:41,465 and you can see layer after layer after layer 72 00:04:41,466 --> 00:04:43,466 after layer of sedimentary rock. 73 00:04:48,466 --> 00:04:50,465 Each layer is a time capsule 74 00:04:50,466 --> 00:04:54,465 with a slice of our continent's epic history locked inside, 75 00:04:54,466 --> 00:04:59,465 stretching hundreds of millions of years into the past. 76 00:04:59,466 --> 00:05:01,465 Every single one of these layers tells its own story 77 00:05:01,466 --> 00:05:03,465 about what North America was like 78 00:05:03,466 --> 00:05:05,465 when that layer was deposited. 79 00:05:05,466 --> 00:05:07,465 So here in one place, 80 00:05:07,466 --> 00:05:09,465 you have this incredible story of our continent 81 00:05:09,466 --> 00:05:11,466 laid out for your viewing pleasure. 82 00:05:17,466 --> 00:05:20,465 But to really tell that story, 83 00:05:20,466 --> 00:05:23,465 I've got to step out of my comfort zone. 84 00:05:23,466 --> 00:05:25,466 Are you ready for a little time travelling? 85 00:05:27,466 --> 00:05:29,465 I'm going to rappel down the cliff 86 00:05:29,466 --> 00:05:33,466 to get up close and personal with these rocks. 87 00:05:35,466 --> 00:05:39,465 Looks like I'm good to step off the edge of the Grand Canyon. 88 00:05:39,466 --> 00:05:41,465 I can't believe I'm doing this. 89 00:05:41,466 --> 00:05:44,466 I really don't like the fact you've put a cactus right here. 90 00:05:47,466 --> 00:05:49,466 This is the moment of truth. 91 00:05:58,466 --> 00:06:00,465 Oh, baby! 92 00:06:00,466 --> 00:06:03,465 This is not the easiest thing to do, 93 00:06:03,466 --> 00:06:07,466 especially in 100-degree heat, but it's worth it. 94 00:06:09,466 --> 00:06:12,466 Every foot I descend takes me further back in time. 95 00:06:19,466 --> 00:06:21,465 The first layer you come to in this part of the canyon 96 00:06:21,466 --> 00:06:24,465 is this pinkish rock I'm hanging next to right now. 97 00:06:24,466 --> 00:06:27,465 It's called the Esplanade Layer, 98 00:06:27,466 --> 00:06:29,465 and like all the rocks in the Grand Canyon, 99 00:06:29,466 --> 00:06:32,466 it's an ancient landscape frozen in time. 100 00:06:38,466 --> 00:06:40,465 300 million years ago, 101 00:06:40,466 --> 00:06:43,465 this place, and all of the American Southwest, 102 00:06:43,466 --> 00:06:47,466 was a vast sea of sand. 103 00:06:49,466 --> 00:06:53,465 Hot, dry winds sculpted an immense desert landscape 104 00:06:53,466 --> 00:06:54,466 of endless dunes. 105 00:06:57,466 --> 00:06:59,465 Over time, the sand compressed 106 00:06:59,466 --> 00:07:02,465 and transformed into the sandstone 107 00:07:02,466 --> 00:07:06,466 that forms the top ledge of the Grand Canyon here today. 108 00:07:08,466 --> 00:07:13,466 Further down, there's evidence of a very different landscape. 109 00:07:16,466 --> 00:07:18,465 About 1,000 feet below the rim of the canyon, 110 00:07:18,466 --> 00:07:22,465 the rock changes to limestone loaded with fossils. 111 00:07:22,466 --> 00:07:24,465 I've got a little fossil coral in my hand. 112 00:07:24,466 --> 00:07:26,465 It's fossils like this that tell us 113 00:07:26,466 --> 00:07:29,466 that this whole landscape was once underwater. 114 00:07:39,466 --> 00:07:43,465 340 million years ago, 115 00:07:43,466 --> 00:07:47,466 a warm, shallow sea covered all of the American Southwest. 116 00:07:50,466 --> 00:07:52,465 Its waters were teeming 117 00:07:52,466 --> 00:07:55,465 with trillions of microscopic marine organisms. 118 00:07:55,466 --> 00:08:01,465 When they died, their skeletons piled up on the seafloor 119 00:08:01,466 --> 00:08:03,465 and compressed into limestone, 120 00:08:03,466 --> 00:08:08,466 forming layers that are hundreds of feet thick. 121 00:08:12,466 --> 00:08:16,465 And so it goes, layer after layer of rock 122 00:08:16,466 --> 00:08:20,465 telling us the story of long-lost landscapes, 123 00:08:20,466 --> 00:08:24,466 each one once the surface of our continent. 124 00:08:31,466 --> 00:08:33,465 And right at the bottom, 125 00:08:33,466 --> 00:08:37,465 you find the granddaddy of Grand Canyon rocks: 126 00:08:37,466 --> 00:08:39,465 Granodiorite. 127 00:08:39,466 --> 00:08:41,465 This rock is more than 4,000 feet 128 00:08:41,466 --> 00:08:44,465 below the rim of the canyon, 129 00:08:44,466 --> 00:08:46,465 and it's one of the oldest rocks of them all. 130 00:08:46,466 --> 00:08:51,465 By measuring the radioactive elements in this granodiorite, 131 00:08:51,466 --> 00:08:53,465 the rock here at the bottom, 132 00:08:53,466 --> 00:08:59,465 geologists have figured out that it formed 1.7 billion years ago. 133 00:08:59,466 --> 00:09:03,465 Old for sure, but not the oldest rock on our continent. 134 00:09:03,466 --> 00:09:06,466 In fact, not even close. 135 00:09:12,466 --> 00:09:14,465 The first rocks on our planet formed 136 00:09:14,466 --> 00:09:17,465 over four billion years ago. 137 00:09:17,466 --> 00:09:21,465 Back then, the whole thing was a lump of molten rock 138 00:09:21,466 --> 00:09:24,466 under constant fire from asteroids. 139 00:09:29,466 --> 00:09:34,466 Eventually, the bombardment slowed and the earth cooled. 140 00:09:38,466 --> 00:09:41,465 It formed a hard, rocky crust, 141 00:09:41,466 --> 00:09:46,465 and as water seeped from the rocks, 142 00:09:46,466 --> 00:09:49,466 oceans soon covered almost the entire planet. 143 00:09:51,466 --> 00:09:53,465 Under an orange methane atmosphere, 144 00:09:53,466 --> 00:09:56,466 there was hardly any land in sight. 145 00:10:00,466 --> 00:10:03,465 So, how did North America and its fellow continents 146 00:10:03,466 --> 00:10:05,466 get started? 147 00:10:13,466 --> 00:10:16,465 To see what the very first land might have looked like, 148 00:10:16,466 --> 00:10:19,465 I'm heading to a place far from our continent, 149 00:10:19,466 --> 00:10:21,465 right in the middle of the Pacific ocean: 150 00:10:21,466 --> 00:10:21,966 Hawaii. 151 00:10:26,466 --> 00:10:29,465 Here, you can witness a force of nature 152 00:10:29,466 --> 00:10:31,466 that creates land from scratch. 153 00:10:39,466 --> 00:10:42,465 From up here, it looks like paradise, 154 00:10:42,466 --> 00:10:46,466 but there's an inferno bubbling under the surface. 155 00:10:51,466 --> 00:10:55,466 Just below us, lava is pouring right out of the mountainside. 156 00:11:15,466 --> 00:11:18,465 I'm flying over Mount Kilauea, 157 00:11:18,466 --> 00:11:23,466 one of the most active volcanoes on earth. 158 00:11:33,466 --> 00:11:36,465 Erupting since 1983, 159 00:11:36,466 --> 00:11:41,465 Mount Kilauea has spewed out ten billion tons of lava 160 00:11:41,466 --> 00:11:45,466 and resurfaced 50 square miles of land. 161 00:12:05,466 --> 00:12:08,465 All land on our planet started out like this, 162 00:12:08,466 --> 00:12:14,465 as lava cooling and turning into dark, heavy volcanic rock. 163 00:12:14,466 --> 00:12:17,465 It would take a dramatic transformation 164 00:12:17,466 --> 00:12:20,465 to turn volcanic islands like this 165 00:12:20,466 --> 00:12:21,465 into the first continents. 166 00:12:21,466 --> 00:12:24,465 I've got two kinds of rocks here. 167 00:12:24,466 --> 00:12:28,465 The first one is this dark, heavy stuff called basalt. 168 00:12:28,466 --> 00:12:30,465 This is the kind of rock you find on ocean floors 169 00:12:30,466 --> 00:12:33,465 and ocean crust and ocean islands like Hawaii. 170 00:12:33,466 --> 00:12:36,465 The second kind of rock is lighter in color 171 00:12:36,466 --> 00:12:38,465 and it's lighter in weight. 172 00:12:38,466 --> 00:12:39,465 It's called granite, 173 00:12:39,466 --> 00:12:42,466 and rocks like this form the stuff of our continents. 174 00:12:47,466 --> 00:12:50,465 You can find granite all over the place in North America, 175 00:12:50,466 --> 00:12:53,465 from the Appalachians on the East Coast 176 00:12:53,466 --> 00:12:57,465 to the sheer rock faces of Yosemite 177 00:12:57,466 --> 00:13:00,466 and the towering peaks of the Rockies. 178 00:13:02,466 --> 00:13:06,465 Without granite and other light rocks, 179 00:13:06,466 --> 00:13:08,465 there might not even be any continents. 180 00:13:08,466 --> 00:13:10,465 Because at one time, 181 00:13:10,466 --> 00:13:12,465 the only rock on the face of the Earth 182 00:13:12,466 --> 00:13:15,466 was volcanic rock like basalt. 183 00:13:17,466 --> 00:13:19,465 The trick is, how do you get the granite in the first place 184 00:13:19,466 --> 00:13:21,466 if you start out with only basalt? 185 00:13:27,466 --> 00:13:29,465 Under the ancient oceans, 186 00:13:29,466 --> 00:13:32,465 our whole planet was covered in basalt, 187 00:13:32,466 --> 00:13:36,466 broken into large chunks called plates. 188 00:13:38,466 --> 00:13:40,465 Deep beneath them, 189 00:13:40,466 --> 00:13:43,465 the heat of the earth softens the rocks 190 00:13:43,466 --> 00:13:47,465 and moves them like a giant conveyor belt. 191 00:13:47,466 --> 00:13:53,465 This pushes and pulls the plates of basalt along the surface 192 00:13:53,466 --> 00:13:57,465 and sometimes even drags them down, 193 00:13:57,466 --> 00:14:01,466 triggering a reaction in the red hot rocks below. 194 00:14:06,466 --> 00:14:10,465 The lighter stuff melts, floats upwards, 195 00:14:10,466 --> 00:14:14,465 and cools into granite, gradually building up 196 00:14:14,466 --> 00:14:19,466 a thick layer of light, buoyant rock. 197 00:14:21,466 --> 00:14:25,465 And this is how you turn heavy volcanic rocks 198 00:14:25,466 --> 00:14:30,466 into the rocks that make continents, including our own. 199 00:14:33,466 --> 00:14:36,465 In southern Canada, just north of Lake Superior, 200 00:14:36,466 --> 00:14:38,465 I'm on the hunt 201 00:14:38,466 --> 00:14:40,466 for some of the oldest rocks on our continent. 202 00:14:43,466 --> 00:14:45,465 I'm Kirk Johnson, here to see Cameron McLean. 203 00:14:45,466 --> 00:14:46,465 Okay, on you go. 204 00:14:46,466 --> 00:14:47,466 Thanks very much. 205 00:14:49,466 --> 00:14:54,465 This is Lac des Iles, a mine in Thunder Bay, Ontario. 206 00:14:54,466 --> 00:14:57,466 This huge open pit is just the tip of the iceberg. 207 00:14:59,466 --> 00:15:01,466 I'll be going way deeper. 208 00:15:10,466 --> 00:15:11,465 How deep are we going right now? 209 00:15:11,466 --> 00:15:13,465 We're going to get off at the 740 level. 210 00:15:13,466 --> 00:15:15,465 That's 740 meters below the surface. 211 00:15:15,466 --> 00:15:17,466 So over 2,000 feet, something like that. 212 00:15:19,466 --> 00:15:20,465 We're going down! 213 00:15:20,466 --> 00:15:21,465 Way down. 214 00:15:21,466 --> 00:15:22,466 Way down! 215 00:15:26,466 --> 00:15:29,465 At the bottom, nearly half a mile down, 216 00:15:29,466 --> 00:15:32,466 I realize the full scale of the mining operation. 217 00:15:43,466 --> 00:15:48,465 Every day, they blast out 3,000 tons of rocks 218 00:15:48,466 --> 00:15:52,465 to find a treasure that formed a long time ago. 219 00:15:52,466 --> 00:15:54,465 Here, we've got a pile of ore 220 00:15:54,466 --> 00:15:56,465 that was just blasted this morning. 221 00:15:56,466 --> 00:15:57,465 We're in the ore now? Yup. 222 00:15:57,466 --> 00:16:00,465 You basically shovel it out, 223 00:16:00,466 --> 00:16:04,465 grind it up, process it, and what do you get? 224 00:16:04,466 --> 00:16:06,465 We get this. 225 00:16:06,466 --> 00:16:08,466 Palladium. 226 00:16:14,466 --> 00:16:17,465 Every day, miners extract nearly $400,000 worth of pall 227 00:16:17,466 --> 00:16:19,466 from these rocks. 228 00:16:22,466 --> 00:16:23,465 This silvery metal 229 00:16:23,466 --> 00:16:28,465 makes our cars' catalytic converters function. 230 00:16:28,466 --> 00:16:32,466 Palladium is 35 times more rare than gold. 231 00:16:35,466 --> 00:16:37,465 But to me, the most valuable thing down here 232 00:16:37,466 --> 00:16:39,466 is the rock the miners throw away. 233 00:16:42,466 --> 00:16:48,465 Geologists have dated the rock here in Lac des Iles 234 00:16:48,466 --> 00:16:51,465 and figured out that it formed nearly three billion years ago, 235 00:16:51,466 --> 00:16:54,465 which is just mind-blowing. 236 00:16:54,466 --> 00:16:56,465 That's almost a billion years older 237 00:16:56,466 --> 00:16:59,466 than the oldest rock at the bottom of the Grand Canyon. 238 00:17:05,466 --> 00:17:10,465 Lac des Iles sits in an ancient chunk of continental crust, 239 00:17:10,466 --> 00:17:14,466 one of the oldest building blocks of North America. 240 00:17:17,466 --> 00:17:20,465 Cooked up nearly three billion years ago, 241 00:17:20,466 --> 00:17:24,465 it merged with other chunks about 1.7 billion years ago 242 00:17:24,466 --> 00:17:28,465 to build the very first version of our continent: 243 00:17:28,466 --> 00:17:29,466 Laurentia. 244 00:17:34,466 --> 00:17:37,465 To this day, the ancient rocks of Laurentia 245 00:17:37,466 --> 00:17:39,465 form a solid foundation 246 00:17:39,466 --> 00:17:42,465 reaching about 100 miles deeper into the Earth 247 00:17:42,466 --> 00:17:45,465 than the rest of North America. 248 00:17:45,466 --> 00:17:48,465 Building Laurentia was a huge step forward 249 00:17:48,466 --> 00:17:51,466 in the making of North America. 250 00:17:53,466 --> 00:17:54,746 But there was some trouble ahead. 251 00:18:05,466 --> 00:18:08,465 150 miles farther south, 252 00:18:08,466 --> 00:18:11,465 the peaceful shores of Lake Superior 253 00:18:11,466 --> 00:18:14,465 hold traces of a cataclysmic event 254 00:18:14,466 --> 00:18:18,466 that very nearly ripped Laurentia apart. 255 00:18:22,466 --> 00:18:24,465 I've always loved beachcombing. 256 00:18:24,466 --> 00:18:27,465 You find amazing things on beaches. 257 00:18:27,466 --> 00:18:30,465 And one thing as a geologist you learn very quickly 258 00:18:30,466 --> 00:18:33,465 is that every single pebble tells a story. 259 00:18:33,466 --> 00:18:34,465 And on this beach, 260 00:18:34,466 --> 00:18:37,466 I'm looking for a very particular kind of pebble. 261 00:18:44,466 --> 00:18:47,465 Oh, here's one, that's excellent. 262 00:18:47,466 --> 00:18:50,465 It doesn't look like much on the backside of it, 263 00:18:50,466 --> 00:18:53,465 but if you turn it over, you can actually see 264 00:18:53,466 --> 00:18:54,465 this incredible banded structure. 265 00:18:54,466 --> 00:18:57,465 This is a classic beautiful Lake Superior agate. 266 00:18:57,466 --> 00:19:02,465 Agates form in cavities in rocks made by gas bubbles, 267 00:19:02,466 --> 00:19:05,465 and the result is this incredible banded 268 00:19:05,466 --> 00:19:07,465 semi-precious gemstone. 269 00:19:07,466 --> 00:19:10,465 Where you find agates, 270 00:19:10,466 --> 00:19:13,465 volcanoes, the source of the gas bubbles, 271 00:19:13,466 --> 00:19:15,466 are usually not far away. 272 00:19:18,466 --> 00:19:21,465 And just a stone's throw from the beach at Gooseberry Falls, 273 00:19:21,466 --> 00:19:27,465 I find a landscape made of nothing but volcanic rock. 274 00:19:27,466 --> 00:19:29,465 That tells me that this place 275 00:19:29,466 --> 00:19:33,466 was not always as serene as it looks today. 276 00:19:38,466 --> 00:19:41,466 A billion years ago, it was a hellish scene. 277 00:19:43,466 --> 00:19:49,465 And geophysicist Emily Wolin has the evidence. 278 00:19:49,466 --> 00:19:51,465 These falls are the record of a series 279 00:19:51,466 --> 00:19:53,465 of volcanic eruptions that happened in this area. 280 00:19:53,466 --> 00:19:55,465 So we have five steps in these falls, 281 00:19:55,466 --> 00:19:57,465 and you can think of each of those steps, 282 00:19:57,466 --> 00:19:59,466 each of these layers as another volcanic eruption. 283 00:20:02,466 --> 00:20:05,465 We have flow after flow of lava coming out, 284 00:20:05,466 --> 00:20:06,465 and believe it or not, what we're seeing here... 285 00:20:06,466 --> 00:20:09,465 This huge stack of basalt... Is really only the tip. 286 00:20:09,466 --> 00:20:12,465 So it goes deep into the ground below us. 287 00:20:12,466 --> 00:20:14,466 It goes much deeper into the ground. 288 00:20:15,466 --> 00:20:19,466 So just how deep does this volcanic rock go? 289 00:20:23,466 --> 00:20:25,465 Emily has brought a piece of equipment 290 00:20:25,466 --> 00:20:28,465 that can help us see below the surface. 291 00:20:28,466 --> 00:20:32,465 It's an array of seismic sensors 292 00:20:32,466 --> 00:20:34,466 that you simply pin into the ground. 293 00:20:36,466 --> 00:20:38,465 Emily is part of a team 294 00:20:38,466 --> 00:20:40,465 that has deployed similar sensors 295 00:20:40,466 --> 00:20:43,465 all around Lake Superior. 296 00:20:43,466 --> 00:20:44,465 Should we test this now? 297 00:20:44,466 --> 00:20:46,465 Absolutely, go for it. 298 00:20:46,466 --> 00:20:47,466 All right. 299 00:20:51,466 --> 00:20:53,465 I'm setting off little earthquakes! 300 00:20:53,466 --> 00:20:54,466 This is great! 301 00:20:55,466 --> 00:20:57,465 Did that work? 302 00:20:57,466 --> 00:20:59,465 Looks good. 303 00:20:59,466 --> 00:21:01,465 The key to this is that seismic waves 304 00:21:01,466 --> 00:21:05,465 travel at different speeds through different kinds of rock. 305 00:21:05,466 --> 00:21:06,465 The waves travel at different speeds 306 00:21:06,466 --> 00:21:08,465 through soil and granite and basalt? 307 00:21:08,466 --> 00:21:09,465 Exactly, yeah. 308 00:21:09,466 --> 00:21:12,465 We've put seismometers all around Lake Superior, 309 00:21:12,466 --> 00:21:14,465 and that tells us the kind of material 310 00:21:14,466 --> 00:21:15,465 that's far, far below our feet 311 00:21:15,466 --> 00:21:17,465 without actually having to drill down. 312 00:21:17,466 --> 00:21:19,465 How much basalt is actually down there? 313 00:21:19,466 --> 00:21:20,465 Underneath Lake Superior, 314 00:21:20,466 --> 00:21:24,465 this basalt and other volcanic rocks associated with it 315 00:21:24,466 --> 00:21:27,465 stretch 55 kilometers into the crust. 316 00:21:27,466 --> 00:21:29,465 That's about 30 miles of volcanic rock. 317 00:21:29,466 --> 00:21:32,465 30 miles of volcanic rock straight down. 318 00:21:32,466 --> 00:21:35,465 That's a lot of volcanic rock. 319 00:21:35,466 --> 00:21:37,465 That is a huge pile of volcanic rock. 320 00:21:37,466 --> 00:21:40,465 This rock is what remains 321 00:21:40,466 --> 00:21:43,465 from one of the biggest volcanic eruptions 322 00:21:43,466 --> 00:21:47,465 in the history of our planet. 323 00:21:47,466 --> 00:21:53,466 Where the water runs today, there once flowed a sea of fire. 324 00:21:56,466 --> 00:21:59,465 A little more than a billion years ago, 325 00:21:59,466 --> 00:22:01,465 Gooseberry Falls was the scene 326 00:22:01,466 --> 00:22:02,465 of one of the most violent events 327 00:22:02,466 --> 00:22:06,465 in North America's history. 328 00:22:06,466 --> 00:22:10,465 Huge torrents of lava poured from the earth off and on 329 00:22:10,466 --> 00:22:12,466 for about 20 million years. 330 00:22:16,466 --> 00:22:20,465 And it wasn't just burning up what's now Minnesota; 331 00:22:20,466 --> 00:22:24,466 the devastation spread much farther. 332 00:22:26,466 --> 00:22:30,465 Evidence of the immense scale comes from surveys 333 00:22:30,466 --> 00:22:32,466 like the ambitious project called the USArray. 334 00:22:34,466 --> 00:22:39,465 It's a huge network of 400 movable seismic sensors. 335 00:22:39,466 --> 00:22:41,465 In the last eight years, 336 00:22:41,466 --> 00:22:46,465 scientists have deployed these across the United States. 337 00:22:46,466 --> 00:22:49,465 It's providing the first complete picture 338 00:22:49,466 --> 00:22:51,465 of the rocks that make up our continent, 339 00:22:51,466 --> 00:22:56,465 almost like a 3-D MRI scan of North America, 340 00:22:56,466 --> 00:23:01,465 revealing an ancient geological wound. 341 00:23:01,466 --> 00:23:04,465 I'm looking at a map of the midwest United States. 342 00:23:04,466 --> 00:23:06,465 What I'm seeing is the distribution 343 00:23:06,466 --> 00:23:08,465 of these basalt flows. 344 00:23:08,466 --> 00:23:09,465 They stretch all the way through Iowa 345 00:23:09,466 --> 00:23:11,465 up into Minnesota, to Lake Superior, 346 00:23:11,466 --> 00:23:12,465 and then back down to Lake Michigan. 347 00:23:12,466 --> 00:23:16,465 It's a huge area about 1,000 miles long. 348 00:23:16,466 --> 00:23:17,465 And this map is really revealing 349 00:23:17,466 --> 00:23:19,465 because it shows a tremendous scar 350 00:23:19,466 --> 00:23:21,465 across the North American continent. 351 00:23:21,466 --> 00:23:26,465 The scar is the result of a huge rift that opened up 352 00:23:26,466 --> 00:23:29,465 in the heart of Laurentia over one billion years ago. 353 00:23:29,466 --> 00:23:35,465 Torrents of lava poured from the Earth. 354 00:23:35,466 --> 00:23:38,465 It was a gash more than 1,000 miles long 355 00:23:38,466 --> 00:23:43,466 that threatened to split our budding continent apart. 356 00:23:45,466 --> 00:23:47,466 But the rift mysteriously stopped. 357 00:23:51,466 --> 00:23:53,465 Today, all that's left of this gaping wound 358 00:23:53,466 --> 00:23:55,465 is the scar tissue, 359 00:23:55,466 --> 00:23:59,465 the basalt we find under Gooseberry Falls 360 00:23:59,466 --> 00:24:01,466 and right through the Midwest. 361 00:24:04,466 --> 00:24:08,465 What happened that kept our young continent whole? 362 00:24:08,466 --> 00:24:11,466 What was it that stopped the rift? 363 00:24:15,466 --> 00:24:17,465 No one knows for sure, 364 00:24:17,466 --> 00:24:21,465 but it could have been our neighbors. 365 00:24:21,466 --> 00:24:23,465 A billion years ago, 366 00:24:23,466 --> 00:24:26,465 some of the other continents on Earth 367 00:24:26,466 --> 00:24:28,465 converged on North America 368 00:24:28,466 --> 00:24:31,466 to form a supercontinent called Rodinia. 369 00:24:35,466 --> 00:24:38,465 It was a titanic group hug, 370 00:24:38,466 --> 00:24:44,465 and when it broke up, the rift had healed. 371 00:24:44,466 --> 00:24:48,466 North America was safe, but far from finished. 372 00:24:52,466 --> 00:24:55,466 Our continent now had a stable core. 373 00:24:57,466 --> 00:25:01,465 But to build its coastlines east and west, 374 00:25:01,466 --> 00:25:02,465 it would take a beating 375 00:25:02,466 --> 00:25:06,466 that went on for hundreds of millions of years. 376 00:25:14,466 --> 00:25:16,465 Making the East Coast we know today 377 00:25:16,466 --> 00:25:19,466 is an epic story of heat and collisions. 378 00:25:26,466 --> 00:25:29,465 Today, I'm hunting for relics 379 00:25:29,466 --> 00:25:33,465 of this continental makeover in Manhattan. 380 00:25:33,466 --> 00:25:35,465 Apartment block. 381 00:25:35,466 --> 00:25:37,465 Apartment block... 382 00:25:37,466 --> 00:25:39,466 Apartment block. 383 00:25:40,466 --> 00:25:42,465 Wow. 384 00:25:42,466 --> 00:25:44,465 No apartment block here. 385 00:25:44,466 --> 00:25:45,466 Rock! 386 00:25:49,466 --> 00:25:53,465 All over the city, you can see outcrops of bedrock. 387 00:25:53,466 --> 00:25:59,465 It's called Manhattan schist, and it's a clue to how the city 388 00:25:59,466 --> 00:26:03,465 and the whole East Coast was made. 389 00:26:03,466 --> 00:26:05,465 These rocky outcrops in Central Park 390 00:26:05,466 --> 00:26:08,465 don't really show up in too many guidebooks, 391 00:26:08,466 --> 00:26:10,465 but they're as important to New York's history 392 00:26:10,466 --> 00:26:12,586 as the Statue of Liberty or the Empire State Building. 393 00:26:17,466 --> 00:26:20,465 Here in the heart of midtown, a brand new apartment complex 394 00:26:20,466 --> 00:26:22,466 will soon rise up from the rocks. 395 00:26:25,466 --> 00:26:27,465 To build the foundation, 396 00:26:27,466 --> 00:26:32,465 the crew has to dig a pit deep into the Manhattan schist. 397 00:26:32,466 --> 00:26:34,465 So what's the toughest thing about drilling into this rock? 398 00:26:34,466 --> 00:26:36,465 This rock is very solid. 399 00:26:36,466 --> 00:26:37,465 We've been here for ten weeks, 400 00:26:37,466 --> 00:26:39,465 and so far we went down about three feet. 401 00:26:39,466 --> 00:26:41,465 Wow, and you're just pounding away 402 00:26:41,466 --> 00:26:42,465 with those rock hammers? 403 00:26:42,466 --> 00:26:44,466 Drilling and hammering away, yeah. 404 00:26:48,466 --> 00:26:49,465 Can I have a try? 405 00:26:49,466 --> 00:26:51,465 Absolutely, here's your chance. 406 00:26:51,466 --> 00:26:52,506 All right, let's go do it. 407 00:26:56,466 --> 00:26:59,465 This is great, I've always wanted to do this. 408 00:26:59,466 --> 00:27:02,465 Takes a little concentration, but it's pretty straightforward. 409 00:27:02,466 --> 00:27:06,466 Up, down, backwards and then down, and then, hammer! 410 00:27:11,466 --> 00:27:13,465 This is incredibly hard rock. 411 00:27:13,466 --> 00:27:16,465 I mean, I could sit in this cab for hours pounding away, 412 00:27:16,466 --> 00:27:17,465 and it would take a long time 413 00:27:17,466 --> 00:27:20,465 to make even a couple of inches of progress. 414 00:27:20,466 --> 00:27:23,465 It's the tough Manhattan schist 415 00:27:23,466 --> 00:27:27,465 that's allowed the city's skyscrapers to soar. 416 00:27:27,466 --> 00:27:30,465 And the thing about schist is that it started its life as mud. 417 00:27:30,466 --> 00:27:35,465 What could have turned mud into this beast of a rock? 418 00:27:35,466 --> 00:27:40,465 I've found some evidence at the bottom of this construction pit. 419 00:27:40,466 --> 00:27:43,466 You can see the rock has a particular shine to it. 420 00:27:44,466 --> 00:27:46,465 This is a mineral called muscovite. 421 00:27:46,466 --> 00:27:50,465 And muscovite forms in big, platy crystals. 422 00:27:50,466 --> 00:27:52,465 Here's one that's almost an inch in diameter, 423 00:27:52,466 --> 00:27:54,465 and what's cool about this stuff 424 00:27:54,466 --> 00:27:56,465 is that it forms in even larger sheets, 425 00:27:56,466 --> 00:27:59,465 and in Moscow, where the word muscovite comes from, 426 00:27:59,466 --> 00:28:02,465 they used to use sheets of muscovite as window glass. 427 00:28:02,466 --> 00:28:06,465 Muscovite forms at over 500 degrees, 428 00:28:06,466 --> 00:28:09,465 and some of the surrounding schist formed 429 00:28:09,466 --> 00:28:11,465 at even higher temperatures. 430 00:28:11,466 --> 00:28:15,465 That gives me an idea about what happened 431 00:28:15,466 --> 00:28:17,466 that turned soft mud into hard rock. 432 00:28:20,466 --> 00:28:22,465 About a half a billion years ago, 433 00:28:22,466 --> 00:28:25,466 a chain of volcanic islands headed towards North America. 434 00:28:29,466 --> 00:28:31,465 Riding the Earth's conveyor belt, 435 00:28:31,466 --> 00:28:34,465 these islands bulldozed mud from the seafloor, 436 00:28:34,466 --> 00:28:38,466 dumped it onto the East Coast, and buried it. 437 00:28:49,466 --> 00:28:53,465 Over time, the mud compressed and baked into the hard bedrock, 438 00:28:53,466 --> 00:28:56,466 or schist, that's shaped the face of New York City. 439 00:28:58,466 --> 00:29:00,465 The skyline of New York City is so familiar. 440 00:29:00,466 --> 00:29:02,465 It's got this incredible group of tall buildings 441 00:29:02,466 --> 00:29:05,465 in the midtown, and then far to the south, 442 00:29:05,466 --> 00:29:06,465 down in downtown Manhattan, 443 00:29:06,466 --> 00:29:09,465 there's a second clump of skyscrapers. 444 00:29:09,466 --> 00:29:11,465 And in between there's much smaller buildings. 445 00:29:11,466 --> 00:29:15,465 And what's going on here is that in midtown, 446 00:29:15,466 --> 00:29:17,465 the Manhattan schist comes near the surface, 447 00:29:17,466 --> 00:29:20,465 and that allows the builders of the skyscrapers 448 00:29:20,466 --> 00:29:23,465 to attach their foundations firmly to bedrock. 449 00:29:23,466 --> 00:29:27,465 The same thing happens to the far south in downtown. 450 00:29:27,466 --> 00:29:29,465 And in between the bedrock dips deep below the surface 451 00:29:29,466 --> 00:29:31,465 where it's covered by gravels and sands. 452 00:29:31,466 --> 00:29:33,465 And there's not so many skyscrapers there... 453 00:29:33,466 --> 00:29:35,465 It's much smaller buildings. 454 00:29:35,466 --> 00:29:38,465 So it's actually the geology that gives 455 00:29:38,466 --> 00:29:41,466 this very American city its very particular look. 456 00:29:50,466 --> 00:29:52,465 While other factors are involved, 457 00:29:52,466 --> 00:29:54,465 today these steel and concrete giants 458 00:29:54,466 --> 00:29:56,465 dominate New York's skyline. 459 00:29:56,466 --> 00:30:00,465 But 440 million years ago, they would have been dwarfed 460 00:30:00,466 --> 00:30:02,466 by something else. 461 00:30:07,466 --> 00:30:11,465 The same collision that created the Manhattan schist 462 00:30:11,466 --> 00:30:14,465 turned a flat coastal plain into something 463 00:30:14,466 --> 00:30:18,465 that's hard to believe... A mountain range. 464 00:30:18,466 --> 00:30:22,465 Standing almost ten times taller than any skyscraper 465 00:30:22,466 --> 00:30:27,466 the Taconic Mountains. 466 00:30:32,466 --> 00:30:34,465 The ancient Taconic Mountains were really big. 467 00:30:34,466 --> 00:30:37,465 They were the size of the Alps, maybe 13,000 feet tall. 468 00:30:37,466 --> 00:30:39,466 Today, very little remains. 469 00:30:43,466 --> 00:30:45,466 So where did they go? 470 00:30:50,466 --> 00:30:53,466 In Manhattan, they eroded away, leaving only bedrock. 471 00:30:56,466 --> 00:30:59,465 And this reveals one of the great geologic truths: 472 00:30:59,466 --> 00:31:01,466 no landscape is permanent. 473 00:31:05,466 --> 00:31:08,465 The formation of New York and the East Coast 474 00:31:08,466 --> 00:31:10,465 was just the first in a series 475 00:31:10,466 --> 00:31:12,465 of gigantic continental collisions 476 00:31:12,466 --> 00:31:15,465 that would transform not just North America, 477 00:31:15,466 --> 00:31:17,466 but the entire planet. 478 00:31:24,466 --> 00:31:27,465 Evidence of this great clash of continents is hidden 479 00:31:27,466 --> 00:31:30,466 in one of the most spectacular vistas of North America. 480 00:31:34,466 --> 00:31:38,466 Over here, Kirk, this is one of the best spots up here. 481 00:31:40,466 --> 00:31:41,465 Wow, what a spot this is. 482 00:31:41,466 --> 00:31:43,466 This is incredible. 483 00:31:50,466 --> 00:31:54,465 This is Zion Canyon. 484 00:31:54,466 --> 00:31:57,465 Its 2,000-foot sandstone cliffs 485 00:31:57,466 --> 00:32:00,466 are among the tallest of their kind on the planet. 486 00:32:06,466 --> 00:32:11,465 Locked inside them are the remnants of a lost world. 487 00:32:11,466 --> 00:32:14,465 Put yourself back in the Jurassic. 488 00:32:14,466 --> 00:32:19,465 200 million years ago, these rocks were endless dunes 00:32:24,466 in a vast desert covering much of the West. 490 00:32:26,466 --> 00:32:29,465 So this sandstone means we had nothing but sand 491 00:32:29,466 --> 00:32:34,465 being blown over an almost lifeless desert. 492 00:32:34,466 --> 00:32:38,465 And you piled up more and more and more, dune after dune. 493 00:32:38,466 --> 00:32:39,465 So these great cliffs of Zion, 494 00:32:39,466 --> 00:32:41,465 these great sandstone cliffs 495 00:32:41,466 --> 00:32:45,465 are actually the stacked fossilized ancient sand dunes. 496 00:32:45,466 --> 00:32:46,466 That's it. 497 00:32:52,466 --> 00:32:54,465 The rocks here in Zion bear witness 498 00:32:54,466 --> 00:32:57,466 to a traumatic phase in our continent's history. 499 00:33:03,466 --> 00:33:08,465 More than 300 million years ago, all the continents on Earth 500 00:33:08,466 --> 00:33:12,465 came together into the biggest landmass ever: 501 00:33:12,466 --> 00:33:20,466 the mega-continent Pangaea. 502 00:33:21,466 --> 00:33:25,465 A towering mountain range rose in its center, 503 00:33:25,466 --> 00:33:27,465 disrupting the climate 504 00:33:27,466 --> 00:33:30,466 and turning great swaths of North America parched and dry. 505 00:33:34,466 --> 00:33:37,465 It was a huge desert. 506 00:33:37,466 --> 00:33:39,465 Everything was so far from a source of moisture 507 00:33:39,466 --> 00:33:41,465 that you couldn't get rainfall. 508 00:33:41,466 --> 00:33:43,465 No moisture in the air. 509 00:33:43,466 --> 00:33:46,465 So what happened to this giant desert? 510 00:33:46,466 --> 00:33:48,466 Why did it disappear? 511 00:33:50,466 --> 00:33:54,465 David has brought me here to look for clues 512 00:33:54,466 --> 00:33:59,465 in the rocks beneath our feet. 513 00:33:59,466 --> 00:34:02,465 But they're not easy to spot. 514 00:34:02,466 --> 00:34:04,465 We're getting close here. 515 00:34:04,466 --> 00:34:05,465 And they'll be round? 516 00:34:05,466 --> 00:34:07,465 Or are they irregular? 517 00:34:07,466 --> 00:34:10,465 They'll look like circles on the rock surface. 518 00:34:10,466 --> 00:34:13,466 Always takes me a little while to get tuned in. 519 00:34:20,466 --> 00:34:21,465 Is this one over here? 520 00:34:21,466 --> 00:34:23,465 Like this thing? 521 00:34:23,466 --> 00:34:26,465 Yup, you got it. 522 00:34:26,466 --> 00:34:27,465 There's that one. 523 00:34:27,466 --> 00:34:28,465 So they're in a row? 524 00:34:28,466 --> 00:34:30,465 You got a scale? 525 00:34:30,466 --> 00:34:33,465 That's about as good as it gets, yeah. 526 00:34:33,466 --> 00:34:36,465 What we've found are strangely regular circles 527 00:34:36,466 --> 00:34:37,466 in the sandstone. 528 00:34:42,466 --> 00:34:47,465 Some of them lined up like a string of pearls. 529 00:34:47,466 --> 00:34:49,466 What could have made them? 530 00:34:52,466 --> 00:34:56,465 I ruled out tracks, I ruled out burrows, 531 00:34:56,466 --> 00:34:59,465 and then when I saw the near perfect alignment 532 00:34:59,466 --> 00:35:01,465 of these in lines and how they cross cut 533 00:35:01,466 --> 00:35:06,465 several different dune deposits, the light finally came on 534 00:35:06,466 --> 00:35:08,465 and I realized it's gotta be earthquakes. 535 00:35:08,466 --> 00:35:10,465 Earthquakes? 536 00:35:10,466 --> 00:35:12,465 How could these little circles 537 00:35:12,466 --> 00:35:15,465 have anything to do with earthquakes? 538 00:35:15,466 --> 00:35:18,465 Turns out the mega-continent Pangaea was too big 539 00:35:18,466 --> 00:35:20,466 for its own good. 540 00:35:22,466 --> 00:35:27,465 Trapped heat rising from the earth caused enormous stress 541 00:35:27,466 --> 00:35:29,465 under the gigantic landmass, 542 00:35:29,466 --> 00:35:32,466 sending earthquakes shuddering across the land. 543 00:35:34,466 --> 00:35:36,465 When they hit the deserts of Zion, 544 00:35:36,466 --> 00:35:40,465 streams of groundwater shot up through the dunes 545 00:35:40,466 --> 00:35:43,466 and erupted in mini volcanoes of quicksand. 546 00:35:47,466 --> 00:35:50,465 So you're telling me that there'd be geysers of sand 547 00:35:50,466 --> 00:35:52,465 shooting out of these holes? 548 00:35:52,466 --> 00:35:55,466 That's what I'm telling you. 549 00:35:57,466 --> 00:36:01,465 Pangaea ruled the Earth for 100 million years, 550 00:36:01,466 --> 00:36:03,465 but, finally, this monster of a continent 551 00:36:03,466 --> 00:36:06,466 couldn't hold it together, and it cracked apart. 552 00:36:09,466 --> 00:36:12,465 The sea flowed into a rift between the continents 553 00:36:12,466 --> 00:36:15,465 to form the Atlantic Ocean. 554 00:36:15,466 --> 00:36:18,465 North America drifted northward and as the climate changed, 555 00:36:18,466 --> 00:36:20,466 it became green again. 556 00:36:28,466 --> 00:36:30,466 Finally, our continent was free. 557 00:36:33,466 --> 00:36:36,465 The break-up of Pangaea more or less marks the moment 558 00:36:36,466 --> 00:36:39,465 that North America became a continent in its own right 559 00:36:39,466 --> 00:36:42,465 with the newly formed Atlantic on one side, 560 00:36:42,466 --> 00:36:44,465 what would become the Pacific on the other side, 561 00:36:44,466 --> 00:36:47,465 and a shape we'd recognize today. 562 00:36:47,466 --> 00:36:52,465 Still, one very important thing was missing: 563 00:36:52,466 --> 00:36:55,466 the Rocky Mountains. 564 00:37:00,466 --> 00:37:05,465 Miles high, stretching all the way from New Mexico to Canada, 565 00:37:05,466 --> 00:37:08,465 you'd think they've been here forever. 566 00:37:08,466 --> 00:37:11,466 But you would be wrong. 567 00:37:15,466 --> 00:37:20,466 These majestic mountains have come and gone several times. 568 00:37:30,466 --> 00:37:33,465 Just outside the Mile High City of Denver, Colorado, 569 00:37:33,466 --> 00:37:36,465 you can see that for the Rocky Mountains, 570 00:37:36,466 --> 00:37:39,466 ups and downs were par for the course. 571 00:37:45,466 --> 00:37:48,465 This is an embarrassingly manicured landscape 572 00:37:48,466 --> 00:37:50,465 for a geologist, 573 00:37:50,466 --> 00:37:52,465 but I'm heading to the 14th hole, 574 00:37:52,466 --> 00:37:54,465 where there's some pretty amazing evidence 575 00:37:54,466 --> 00:37:58,466 for the forces involved in the uplift of the Rocky Mountains. 576 00:38:01,466 --> 00:38:03,465 Hey Kirk, how are you? 577 00:38:03,466 --> 00:38:05,465 Good to see you. 578 00:38:05,466 --> 00:38:10,465 Drone expert Jon Fredericks and I are gonna take 579 00:38:10,466 --> 00:38:14,465 his state of the art eye in the sky for a little spin. 580 00:38:14,466 --> 00:38:16,466 All right, let's take off. 581 00:38:29,466 --> 00:38:32,466 The drone camera reveals a bizarre landscape. 582 00:38:35,466 --> 00:38:38,466 Jagged slabs of sandstone jutting out of the ground. 583 00:38:39,466 --> 00:38:40,465 Oh, look at that. 584 00:38:40,466 --> 00:38:42,465 Incredible. 585 00:38:42,466 --> 00:38:45,466 Just a beautiful landscape there. 586 00:38:50,466 --> 00:38:51,465 This is like being a bird 587 00:38:51,466 --> 00:38:53,465 and that's what geologists want to do, 588 00:38:53,466 --> 00:38:55,465 they want to get up in the air and look down on these rocks. 589 00:38:55,466 --> 00:39:00,465 And I can see just a beautiful perspective. 590 00:39:00,466 --> 00:39:02,465 These are layers of sandstone, they started off as sand, 591 00:39:02,466 --> 00:39:04,465 which means they were originally horizontal. 592 00:39:04,466 --> 00:39:06,465 Now they're tilted up. 593 00:39:06,466 --> 00:39:08,465 It's the kind of landscape you look at and wonder, 594 00:39:08,466 --> 00:39:09,466 what happened here? 595 00:39:15,466 --> 00:39:18,465 If you take a closer look at the sandstone slabs, 596 00:39:18,466 --> 00:39:21,466 you'll find some clues to how they got here. 597 00:39:23,466 --> 00:39:26,465 Mixed in with the finer sand grains are big pebbles 598 00:39:26,466 --> 00:39:28,465 with sharp edges. 599 00:39:28,466 --> 00:39:30,465 These are way too big to have been blown by wind. 600 00:39:30,466 --> 00:39:32,465 And given the size of these particles 601 00:39:32,466 --> 00:39:35,465 and how angular they are, there's probably only one way 602 00:39:35,466 --> 00:39:37,465 to get this kind of sediment moved along 603 00:39:37,466 --> 00:39:38,465 and that's by a river. 604 00:39:38,466 --> 00:39:41,466 And fast-flowing rivers begin in big mountains. 605 00:39:45,466 --> 00:39:47,465 So I'm thinking I'm looking at a sandstone that was formed 606 00:39:47,466 --> 00:39:48,465 near a mountain range. 607 00:39:48,466 --> 00:39:52,465 But what mountains? 608 00:39:52,466 --> 00:39:54,465 It can't be the Rockies. 609 00:39:54,466 --> 00:39:57,466 This sandstone formed way before they even existed. 610 00:39:58,466 --> 00:40:00,466 So what's the story? 611 00:40:06,466 --> 00:40:10,465 Standing here 300 million years ago, 612 00:40:10,466 --> 00:40:15,466 I'd be witnessing the birth of a long-lost mountain range. 613 00:40:17,466 --> 00:40:20,465 Called the Ancestral Rockies, 614 00:40:20,466 --> 00:40:22,546 they were nearly as high as the Rockies we see today. 615 00:40:31,466 --> 00:40:34,465 But over millions of years, 616 00:40:34,466 --> 00:40:37,465 rivers and rain ground down these ancient mountains 617 00:40:37,466 --> 00:40:40,465 and reduced them to sand and gravel, 618 00:40:40,466 --> 00:40:44,465 which compressed into sandstone. 619 00:40:44,466 --> 00:40:47,465 So the slabs we see on the golf course 620 00:40:47,466 --> 00:40:51,466 are all that's left of this long-forgotten mountain range. 621 00:40:53,466 --> 00:40:56,465 But how come these layers that were once horizontal 622 00:40:56,466 --> 00:41:00,465 are now standing on their heads? 623 00:41:00,466 --> 00:41:03,465 What was the force that was strong enough 624 00:41:03,466 --> 00:41:06,466 to push up hundreds of feet of layered rock up into the sky? 625 00:41:12,466 --> 00:41:15,465 70 million years ago, the rock that makes our modern Rockies 626 00:41:15,466 --> 00:41:20,466 was deep underground and covered by 10,000 feet of layered rock. 627 00:41:24,466 --> 00:41:28,465 But then something happened hundreds of miles away, 628 00:41:28,466 --> 00:41:30,465 on the western edge of North America: 629 00:41:30,466 --> 00:41:33,465 a slab of ocean floor diving deep into the earth 630 00:41:33,466 --> 00:41:36,465 suddenly starts attacking our continent, 631 00:41:36,466 --> 00:41:40,466 bulldozing right through its foundations. 632 00:41:42,466 --> 00:41:46,465 Far inland, this forced up a massive mountain range... 633 00:41:46,466 --> 00:41:48,466 The Rockies 2.0. 634 00:41:56,466 --> 00:42:02,465 They lifted up the 10,000 feet of layered rock above them, 635 00:42:02,466 --> 00:42:05,465 tilting that ancient layer of sandstone, 636 00:42:05,466 --> 00:42:10,465 which erosion then sculpted into sharp, angled slabs: 637 00:42:10,466 --> 00:42:12,465 the jagged red monoliths 638 00:42:12,466 --> 00:42:14,466 that make this golf course so special. 639 00:42:17,466 --> 00:42:19,465 The colossal mountains that created them 640 00:42:19,466 --> 00:42:23,465 eventually eroded down. 641 00:42:23,466 --> 00:42:26,465 But then, about ten million years ago, 642 00:42:26,466 --> 00:42:31,465 the entire region was lifted a mile above sea level, 643 00:42:31,466 --> 00:42:38,465 giving us the spectacular Colorado Rockies we see today, 644 00:42:38,466 --> 00:42:40,466 a true signature landscape of the American West. 645 00:42:43,466 --> 00:42:44,465 They're still under construction, 646 00:42:44,466 --> 00:42:48,465 pushing up from below even as erosion 647 00:42:48,466 --> 00:42:51,466 keeps carving away at their majestic peaks. 648 00:42:58,466 --> 00:43:01,465 Now there's just one more big piece to add 649 00:43:01,466 --> 00:43:03,466 to our continental puzzle. 650 00:43:05,466 --> 00:43:08,466 The magnificent landscapes of the West Coast. 651 00:43:13,466 --> 00:43:15,465 Like Big Sur, 652 00:43:15,466 --> 00:43:20,465 the snow-capped volcanoes of the Pacific Northwest, 653 00:43:20,466 --> 00:43:25,466 and the fjords and islands of British Columbia and Alaska. 654 00:43:40,466 --> 00:43:42,465 To find out what made these landscapes, 655 00:43:42,466 --> 00:43:45,466 I'm gonna have to crack open a few rocks. 656 00:43:49,466 --> 00:43:51,465 Of fossil hunters Tow 657 00:43:51,466 --> 00:43:54,465 to this remote beach. 658 00:43:54,466 --> 00:43:56,465 So what time is it? 659 00:43:56,466 --> 00:43:58,465 I think the tide has probably turned. 660 00:43:58,466 --> 00:44:00,465 MAN: 7:41. 661 00:44:00,466 --> 00:44:01,465 So we have about three hours right? 662 00:44:01,466 --> 00:44:03,465 So I'm gonna turn you guys loose on this outcrop 00:44:06,465 and just scream if you find something good, all right? 664 00:44:06,466 --> 00:44:10,466 I've been here before and I really wanted to come back. 665 00:44:20,466 --> 00:44:21,465 Nothing. 666 00:44:21,466 --> 00:44:23,465 It's just rock. 667 00:44:23,466 --> 00:44:26,466 You gotta break a lot of rock though to find fossils. 668 00:44:28,466 --> 00:44:32,465 There's nothing quite like splitting open slabs of rock... 669 00:44:32,466 --> 00:44:35,465 You never know what you will find hidden inside. 670 00:44:35,466 --> 00:44:38,465 The bigger the slab you can lift up the better, 671 00:44:38,466 --> 00:44:40,465 because you just can't... I can't emphasize it enough. 672 00:44:40,466 --> 00:44:42,466 I think you've been emphasizing it quite a bit. 673 00:44:46,466 --> 00:44:47,465 We've been cracking rocks for hours 674 00:44:47,466 --> 00:44:50,466 and we're running out of time. 675 00:44:53,466 --> 00:44:56,466 The tide is coming in, guys... It's about 20 feet behind us. 676 00:44:57,466 --> 00:44:58,465 There it goes. 677 00:44:58,466 --> 00:45:00,465 I have the rock, you take that rock. 678 00:45:00,466 --> 00:45:02,465 Peel this one back. 679 00:45:02,466 --> 00:45:03,466 And no fossil. 680 00:45:07,466 --> 00:45:09,465 Big split. 681 00:45:09,466 --> 00:45:10,465 No fossil. 682 00:45:10,466 --> 00:45:11,465 Big nothing! 683 00:45:11,466 --> 00:45:13,465 With the tide on our heels, 684 00:45:13,466 --> 00:45:15,466 we get one last shot. 685 00:45:17,466 --> 00:45:19,465 You're on it. 686 00:45:19,466 --> 00:45:21,465 My fingers. 687 00:45:21,466 --> 00:45:23,465 Okay, we're... whoa. 688 00:45:23,466 --> 00:45:24,465 Oh, yes! 689 00:45:24,466 --> 00:45:29,465 Okay now, get this edge right here and just peel it back. 690 00:45:29,466 --> 00:45:31,466 Real slow... one, two, three. 691 00:45:36,466 --> 00:45:37,465 Look, there it is. 692 00:45:37,466 --> 00:45:39,465 Oh, my God. 693 00:45:39,466 --> 00:45:43,466 A fossilized palm frond. 694 00:45:44,466 --> 00:45:46,466 That is unbelievable! 695 00:45:48,466 --> 00:45:52,465 That, my friends, is a palm frond. 696 00:45:52,466 --> 00:45:57,465 The reason I'm so excited is we're not on 697 00:45:57,466 --> 00:45:58,746 the sunny shores of California... 698 00:46:01,466 --> 00:46:05,465 We're in Alaska! 699 00:46:05,466 --> 00:46:10,465 What's a palm leaf doing so far north? 700 00:46:10,466 --> 00:46:11,465 I'll tell you what. 701 00:46:11,466 --> 00:46:15,465 If you have a palm tree, the ground doesn't freeze. 702 00:46:15,466 --> 00:46:19,465 This palm grew here when the climate in Alaska 703 00:46:19,466 --> 00:46:23,465 and the rest of the world was much warmer. 704 00:46:23,466 --> 00:46:28,465 But there's something else going on here, 705 00:46:28,466 --> 00:46:31,465 because we've also found fossilized corals 706 00:46:31,466 --> 00:46:33,465 on a neighboring island. 707 00:46:33,466 --> 00:46:36,466 And they're much older than the palm frond. 708 00:46:38,466 --> 00:46:40,465 We know these corals lived near the equator, 709 00:46:40,466 --> 00:46:44,466 so how did their fossils wind up here in Alaska? 710 00:46:48,466 --> 00:46:55,465 Turns out the corals hitched a ride on strings of islands 711 00:46:55,466 --> 00:46:59,465 moving up from the Pacific, smacking into North America 712 00:46:59,466 --> 00:47:02,466 over millions of years. 713 00:47:05,466 --> 00:47:08,465 These travelling landmasses radically re-shaped 714 00:47:08,466 --> 00:47:11,466 our Pacific coastline. 715 00:47:14,466 --> 00:47:17,465 Imagine an island the size of Japan and imagine that island 716 00:47:17,466 --> 00:47:19,465 off the coast of North America drifting towards the coast 717 00:47:19,466 --> 00:47:21,465 at about three inches a year. 718 00:47:21,466 --> 00:47:25,465 Then imagine this field of logs is like lots of little Japans, 719 00:47:25,466 --> 00:47:27,465 log after log smacking in and sliding north, 720 00:47:27,466 --> 00:47:29,465 smacking in and sliding north. 721 00:47:29,466 --> 00:47:31,465 And you start to see a model 722 00:47:31,466 --> 00:47:34,466 for how the west coast of North America grew. 723 00:47:36,466 --> 00:47:41,465 It was a titanic geological logjam 724 00:47:41,466 --> 00:47:44,465 that grafted thousands of miles of new coastline 725 00:47:44,466 --> 00:47:48,465 onto our continent and still had enough power 726 00:47:48,466 --> 00:47:51,465 to push up the spectacular coastal mountain ranges 727 00:47:51,466 --> 00:47:53,466 of Alaska and British Columbia. 728 00:47:55,466 --> 00:47:58,465 The West coast is the most recent addition 729 00:47:58,466 --> 00:48:02,465 in the great continental construction project 730 00:48:02,466 --> 00:48:06,466 that built North America, but it's far from complete. 731 00:48:12,466 --> 00:48:15,465 On the coast of California, 732 00:48:15,466 --> 00:48:19,465 it's easy to find the signs of ongoing work. 733 00:48:19,466 --> 00:48:23,465 Just 30 miles north of San Francisco, 734 00:48:23,466 --> 00:48:27,465 Tomales Bay is one of the most enigmatic places 735 00:48:27,466 --> 00:48:28,465 on the West Coast, 736 00:48:28,466 --> 00:48:33,465 and a favorite spot for geologist Lisa White. 737 00:48:33,466 --> 00:48:34,465 Growing up in San Francisco, 738 00:48:34,466 --> 00:48:35,746 I always loved this area so much. 739 00:48:39,466 --> 00:48:41,465 It's really a curious situation here because the rocks 740 00:48:41,466 --> 00:48:45,465 on that side of the bay, that whole peninsula has been 741 00:48:45,466 --> 00:48:48,465 moving for millions of years from an area further south. 742 00:48:48,466 --> 00:48:50,465 And part of the puzzle 743 00:48:50,466 --> 00:48:52,466 is we're standing on the San Andreas fault. 744 00:48:58,466 --> 00:49:00,465 Hidden deep under this bay 745 00:49:00,466 --> 00:49:03,466 is an enormous crack in the earth. 746 00:49:06,466 --> 00:49:08,466 This is the San Andreas fault. 747 00:49:12,466 --> 00:49:15,465 It cuts right through Tomales Bay 748 00:49:15,466 --> 00:49:17,465 and runs 800 miles through California, 749 00:49:17,466 --> 00:49:22,465 separating two huge chunks of the earth's crust... 750 00:49:22,466 --> 00:49:30,465 The Pacific plate and the North American plate... 751 00:49:30,466 --> 00:49:32,466 Which are sliding in opposite directions. 752 00:49:36,466 --> 00:49:39,465 We're sitting on the North American plate 753 00:49:39,466 --> 00:49:40,465 and the Pacific plate over there 754 00:49:40,466 --> 00:49:45,465 relative to where we're sitting is moving to the northwest. 755 00:49:45,466 --> 00:49:47,465 So that whole peninsula is moving along. 756 00:49:47,466 --> 00:49:48,465 How fast is it going? 757 00:49:48,466 --> 00:49:50,465 That whole peninsula is moving 758 00:49:50,466 --> 00:49:52,465 about the speed that our fingernails grow, 759 00:49:52,466 --> 00:49:54,466 so couple of inches every year. 760 00:49:59,466 --> 00:50:01,465 Tension in the San Andreas 761 00:50:01,466 --> 00:50:05,465 can trigger violent earthquakes, like the one that devastated 762 00:50:05,466 --> 00:50:10,466 San Francisco in 1906 and many others since. 763 00:50:14,466 --> 00:50:17,465 1906, 1989, 1993... 764 00:50:17,466 --> 00:50:18,465 You name them. 765 00:50:18,466 --> 00:50:20,465 Pretty much most decades we can think of 766 00:50:20,466 --> 00:50:23,465 significant earthquakes that happened. 767 00:50:23,466 --> 00:50:26,465 The power of the moving plates 768 00:50:26,466 --> 00:50:30,465 constantly changes the face of California, 769 00:50:30,466 --> 00:50:33,465 with surprising long-term results. 770 00:50:33,466 --> 00:50:36,465 So what this is means is that sooner or later Los Angeles 771 00:50:36,466 --> 00:50:40,465 is going to pull up right next to San Francisco. 772 00:50:40,466 --> 00:50:44,466 The view from the Hollywood hills will be very different. 773 00:50:47,466 --> 00:50:49,465 Imagine that. 774 00:50:49,466 --> 00:50:51,465 So two towns that don't even like each other very much 775 00:50:51,466 --> 00:50:53,465 will be neighbors. 776 00:50:53,466 --> 00:50:57,465 But what understanding the geology of California 777 00:50:57,466 --> 00:50:59,506 really illustrates is just how dynamic the state is. 778 00:51:01,466 --> 00:51:03,465 California is one of those places 779 00:51:03,466 --> 00:51:06,466 where the forces under our feet really make themselves known. 780 00:51:11,466 --> 00:51:16,465 Our wild ride across North America and back in time 781 00:51:16,466 --> 00:51:19,466 reveals these forces are relentlessly at work. 782 00:51:21,466 --> 00:51:24,465 Continent building never ends 783 00:51:24,466 --> 00:51:26,465 because we know one thing for sure in geology... 784 00:51:26,466 --> 00:51:29,466 Nothing ever stays the same for very long. 785 00:51:30,466 --> 00:51:34,466 North America has seen some amazing transformations. 786 00:51:37,466 --> 00:51:41,466 It took billions of years to take the shape it is today. 787 00:51:44,466 --> 00:51:47,465 But far from reaching the end of our story, 788 00:51:47,466 --> 00:51:51,465 we're really just embarking on the next chapter: 789 00:51:51,466 --> 00:51:55,466 how geology shaped life on our continent. 790 00:52:17,466 --> 00:52:19,465 The three-part NOVA series "Making North America" The investig 791 00:52:19,466 --> 00:52:21,465 is available on DVD. 792 00:52:21,466 --> 00:52:27,465 To order, visit shoppbs.org or call 1-800-PLAY-PBS. 793 00:52:27,466 --> 00:52:29,466 NOVA is also available for download from iTunes.