Deep Time: Discovering an Ancient Earth

We might well be the first species to ask, and even begin to answer, some big questions about the world around us: Who are we? Where are we? and When are we? Geology joins some heavy hitters, like evolutionary biology and cosmology, when it comes to providing major insights, particularly into the latter question.This first module begins with a look at science in general, how it works and where it came from. We then address the historical beginnings of a “science of the earth” (geology) and how, from its very inception, it pointed towards an earth of immense age, the business of Deep Time. The module wraps up with an introduction to the assessment of rock and mineral age determination using both qualitative and isotopic methods.

The power of science is no better exemplified than through its ability to peer into the most remote depths of Deep Time. In this second module we take a cursory “highlight trip” through a host of very ancient and key origins, from the universe itself to stars and planets, and then to Earth’s first oceans, atmosphere, crust, and life. We take a literal deep dive into the underpinnings of the North American continent, the so-called Precambrian basement. Using rock and mineral analysis, radiometric dating, seismology, and the treasure trove of deep-earth materials brought to the surface by kimberlitic “diamond-pipe” eruptions, geologists have put together an understanding of how North America, and continents in general, grow through time.

We tackle the story of North America, as it emerges from the Precambrian into the Phanerozoic Eon (i.e., Paleozoic, Mesozoic, Cenozoic Eras). The story is read from the book of rock layers, and as such we review some of the language of geology—rocks and the rock-cycle. We VISIT (via both lecture and virtual-video-field trip) the puzzling yet pervasive Great Unconformity, an enormous gap in the rock record that sits directly below the first strata with shell fossils. We consider the marine waters that washed onto and off the land, as climate and tectonics drove changes in sea-level. Lastly, as the Pangea Super-Continent coalesced in the Late Paleozoic, we see the rise of the Ancestral Rocky Mountains. Note: This module contains the first two of three Video Field Trip Outings to Flagstaff Mountain, near Boulder, Colorado.