The main focus of this class is to provide you with tools that are useful for interpreting Earth history from the sedimentary record and for understanding resources such as ground water and petroleum.
Four Main Concepts:
Accommodation Space: The area available for sediment to be deposited, usually the space between the sedimentary surface and sea level. This concept is very important because it allows you to predict the general types of rocks that can be deposited in an area and classes of organisms that might be present. Tracking lateral and temporal changes in accommodation space is the basic concept behind sequence stratigraphy. To a first order approximation, accommodation space depends on sea level (or base level), subsidence, and sediment supply. About 1/3 of the class is devoted to this topic!
Tectonics and Sedimentation: The sedimentary record contains vast volumes of information about tectonic processes because tectonics influence sediment supply and subsidence, which affect accommodation space, etc. We will emphasize fluvial sedimentation in active tectonic environments this year because there are several students taking the class that are combining structural mapping and stratigraphic analysis to interpret tectonic processes for their research.
Subsurface Interpretation Technical Skills: Well log and seismic stratigraphy analysis. Many jobs in the environmental and oil industries involve characterizing subsurface geology using well logs and seismic data. Understanding fluid flow is critical for characterizing water resources, contaminant transport, and hydrocarbon resources. Well logs and seismic stratigraphy are the two most common subsurface data types and are used to interpret the context of geochemical analyses. They are sometimes supplemented by well chips or core to give “real” rock data. We will use these techniques in lab.
Turning Sediments into Rocks: Diagenesis. In GEL109, we mostly talk about sediments and depositional environments. However, we mostly look at rocks. After deposition, sediments experience dewatering, compaction, cementation, and mild metamorphism, each of which changes the characteristics of the sediments. It is important to understand how these processes affect your interpretations of depositional environments, the porosity and permeability of the sediments/rocks (which influences water and hydrocarbon volumes and flow), and reactions that take place (which affect water quality and mineralogy).