Self-Guided Discovery Pathways through the Cretaceous Earth System
Why Study the Cretaceous?
The Cretaceous Period is a remarkable time in Earth history. It is a time when dinosaurs roamed (and became extinct) on the Earth's surface, the global climate was significantly warmer, sea level was higher, and concentrations of atmospheric carbon dioxide may have contributed to an ancient analog of a "greenhouse" environment.
It was also a time of major tectonic plate reorganization, Laramide- and Sevier-style deformation, and creation of the great Sierra Nevada, Idaho and Boulder batholiths, and related volcanic fields. Events that occurred in the Cretaceous continue to have tremendous implications for our society ranging from the development of geologic structures that may contribute to contemporary seismic hazards, and in our societal reliance on energy (coal, coal-bed methane, oil and gas) and mineral (e.g. copper deposits at Butte, MT) resources that formed at that time.
The Cretaceous World, [Skelton et al., 2003] provides an excellent overview of the state of the Earth in the Cretaceous.
Learning About the Cretaceous in an Earth System Context
The Cretaceous Period also provides an excellent opportunity to demonstrate how collections of digital resources can support an Earth System Approach to learning. Earth system science focuses on the interrelationships among different components of the Earth system. It reveals the transport and storage of mass and energy throughout the Earth system and the processes that operate on this dynamic, heterogeneous, and complex planet. Global cycling and positive and negative feedback mechanisms are important concepts in Earth system science. Earth system science also recognizes the importance of interactions between Earth and the biota that live on our planet, including humanity.
The collection of resources in All Things Cretaceous provides a wealth of information to support learning about this fascinating period of Earth history. This web-mediated learning environment allows learners to readily follow lines of inquiry between related topics, or to dig deep to comprehensively investigate a single topic of interest.
Where to start?
Garrett Hardin's First Law of Ecology [Hardin, 1985] (and by extension, of Earth system science) is, "Everything is connected to everything else". These suggested discovery pathways through the Cretaceous Period offer something of interest for nearly everyone, and readily demonstrate the interconnectedness of All Things Cretaceous. So, it doesn't really matter where you start -- pick a topic that you've been curious about, something that may impact your life, or something that seems so out-of-the-ordinary that you just have to find out more. The motivation for learning is often rooted in activities that are goal-directed, where the task demonstrates knowledge or skills, or that elicits curiosity (see Edelson, 2001 ). Here are some self-guided discovery pathways to explore the Cretaceous system that will hopefully motivate learning by promoting a sense of wonder and curiosity or a compelling need to know. Use these links to find the evidence to address the suggested questions, and to develop and pursue your own questions!
Start with dinosaurs
Why? Because they're cool! How did the dinosaurs live, how did they become extinct, what else was living in the Cretaceous? What do we know about the Cretaceous climate? How was the climate affected by global tectonics and paleogeography, and how did this affect global sea level? How and where did Cretaceous sedimentary basins form and how are they related to Cretaceous-age economic resources?
Start with plate tectonics
Many introductory physical geology, historical geology, and Earth system courses use plate tectonics as a unifying theme. How have Cretaceous mountain-building events affected stratigraphy, the formation and distribution of sedimentary basins, and carbon-based energy resources? How have Cretaceous mountain-building events affected magmatism, paleogeography, and combined with emission of volcanic gases, how have these affected the Cretaceous climate?
The importance of natural resources to our society is of obvious importance, but what are the consequences of exploration, development and use of commodities such as coal bed methane? What are the impacts on human health as a result of a century of hard rock mining of the metal deposits hosted by the Cretaceous Boulder batholith that has left the largest EPA Superfund site in America? What tectonic conditions resulted in magmatism that produced mineral deposits, and produced the stratigraphy and sedimentary basins that host carbon-based energy resources? How do these sedimentary deposits record information ancient sea level, climate, and ancient life?
Start with climate
How does the Cretaceous climate compare with the Earth's present climate, and what lessons can we learn? How is the climate affected by tectonics, paleogeography and magmatism? How has the climate affected sea level and life forms? How are these related to stratigraphy and sedimentary basins? How have life forms, particularly plants and microbes contributed to the formation of energy resources?