Billions of cubic kilometers of quartz sand were washed outward from the center of the continents and deposited along coastlines 400 to 550 million years ago. These sands solidified into rock, becoming the largest continuous sedimentary deposit ever formed on Earth. Such rocks drape the underlying igneous and metamorphic “basement” rocks on all continents and are often called “blanket” or epicratonic (on top of the continent) sandstones. These sandstones are important because they contain water aquifers and petroleum reservoirs. Yet scientists know little about how or why these massive sandstone deposits formed. Based on our ongoing fieldwork in the United States and in the Middle East, our scientific team is trying to understand how this sedimentation event might have occurred. We hypothesize that continental migration, together with the unique characteristics of prevegetated landscapes, may have triggered the rapid washing of sands from the interiors of continents toward their coasts.
Little is known about how or when the western coast of North America formed during the breakup of the ancient supercontinent Rodinia. Previous studies suggest that as the supercontinent rifted (or tore apart), a large fragment drifted away and was stretched like taffy to form a coastline much like that of the eastern United States. This fragment may have originally been attached to what is now Australia, Antarctica, or Siberia. Scientists continue to seek answers to questions about this event. For example, when or how did this occur, which of these fragments was originally attached to the western United States, and what were the evolutionary or environmental impacts of this supercontinent separation? Our research team is working to fill in some of these knowledge gaps by collecting geochronologic, geochemical, paleomagnetic, and environmental data from 530 to 600 million-year-old volcanic rocks that are exposed throughout the Rocky Mountains.
Colorado houses a rich sedimentary record of earth history, including outcrops formed during the late Cretaceous extinction (the period when dinosaurs vanished from the earth). Yet in the shadow of such exposures lie rocks that house records of two other massive extinctions: the end-Devonian and Permian-Triassic mass extinctions. The end-Devonian extinction has only recently been discovered in Colorado. In the White River National Forest region, this event is recorded in 360 million year old sedimentary rocks that were originally deposited along the border of what was a sea. Along the Front Range and in the eastern grasslands, there are 250 million-year-old sedimentary rocks that were either deposited along the edge of salt flat or the edge of an alkaline lake, like the Great Salt Lake of Utah. These poorly-known rocks have not been well-studied, but may contain the signature of the Permian-Triassic event, the largest mass extinction in earth history. Citizen scientists and I are working together to decipher the atmospheric, oceanic, magnetic, and paleontological signatures for both of these extinction events.
Colorado is rich in natural resources, including plenty of economically valuable commodities such as water, sunlight, wind, arable land, minerals, oil, and natural gas. Colorado also has abundant natural resources of aesthetic and cultural importance, such as: forests, parks, monuments, and open spaces that are held in trust for the public. Yet Colorado’s population is growing rapidly and our impact on our environment, and on these resources, increases every year. In light of these impacts, scientists are evaluating possible outcomes as our community moves forward, including:
- What will Colorado be like 40-50 years from now?
- What natural resources will be exhausted, unavailable, or contaminated for the next generation of Coloradans?
- What aspects of our environment or lifestyle will be worse than they are today, and which will remain the same or be better?
- How do our actions fit into the larger, global changes in climate and resource availability that are occurring?
- What can we do about any of these things?
To address these questions, we are working with colleagues to develop predictive models for assessing what the future characteristics of Colorado will be, given our current behavioral, economic, and resource use trajectories. We are also evaluating which behavioral, technological, or policy changes will have an effective impact on the Colorado of the future, and which make scientific and economic sense to implement. In many respects, we control what Colorado will be like for the next generation, and are uniquely poised to make informed decisions that will have a positive impact on that future.