COG3 Seminar: Lizzy Trower (University of Colorado)
Physical processes in chemical sediments: the role of sediment transport in ooid growth and the production of carbonate mud
I will present experimental, modeling, and field data sets to examine two long-standing puzzles in carbonate sedimentology: ooids and carbonate mud. Substantial debate persists concerning the roles of physical, chemical, and microbial processes in the production of both of these important and abundant types of carbonate sediment, including whether carbonate precipitation is primarily driven by seawater chemistry or biological activity, and what role—if any—sediment transport and abrasion play. To test these ideas, I developed an approach to study carbonate sediment transport in the laboratory and observe the consequences of transport in the field—these observations indicate that abrasion plays a significant role both in controlling ooid size and in production of carbonate mud, with important implications for interpreting the carbonate rock record.
About the Speaker
I am a chemical sedimentologist: I study how and why chemical sediments form and lithify, with the goal of better understanding how chemical sedimentary rocks (e.g., carbonates, chert, iron formations) record chemical, physical, and biological paleoenvironmental conditions. Chemical sediments provide a key geobiological record – preserving a physical record of fossil life forms and depositional environments and a geochemical record of seawater and pore fluid chemistry. I am particularly interested in applying my work to Precambrian chemical sediments, which formed prior to the evolution of biomineralizing organisms. My research encompasses lab experiments, modeling, petrography, in situ geochemistry, and fieldwork, spanning modern environments to Precambrian time. My general philosophy is to use experiments and models to understand some key process – for example, abrasion of carbonate sand – then move to a modern environment to test how well these models work in a natural system, and finally to apply what I have learned to the rock record to decipher something new about an ancient surface environment.
About this Seminar
The Chemical Oceanography, Geology, Geochemistry, and Geobiology Seminar [COG3] is a student-run seminar series. Topics include chemical oceanography, geology, geochemistry, and geobiology. The seminars take place on Fridays from 10-11am in Building E25, Room 119, unless otherwise noted (term-time only).