Physical Geology lecture outline

Physical Geology lecture outline - Sedimentary rocks

Intro comments:

processes accessible, and observable and therefore one can use uniformitarianism as an approach.
first goal? -> identify sedimentary rocks, their components, textures and structures.
next goal? -> reconstruction of changing depositional environments/systems.
another goal -> resource exploration, where are source beds?
an example of interpreting the depositional environment.

Common mineral components in sedimentary rocks:

common minerals in the source rock, i.e. continental crust -> feldspars, quartz, micas, amphiboles.
quartz - why is it so common?
clays - (large group of submicroscopic sheet silicates) - how are they formed?
feldspar - what does its presence tell you about the conditions of deposition?
carbonates - the significance of their distribution?
other minerals.

What are important factors in classification of sedimentary rocks?

Identification flow chart for sedimentary rocks:

Saga of sedimentary rocks, a tale of 4 parts:

weathering and grain production in source terranes: the beginning.
erosion and transport: the long journey.
deposition: RIP
lithification: from loose sediment to a hard rock.

Sedimentary structures and the information they contain:

Submarine debris flows and turbidites, sedimentation as episodic events.

Stratigraphy, the description of stacked sediments:

stratigraphic columns: graphical description of vertical sequence of strata at a local.
example from Svalbard.
Group -> Formation -> Member -> Bed (formal stratigraphic units from large to small).
correlations and fence diagrams.

Shifting depositional environments and the sedimentary record:

of a lake.
of a delta.
of a reef complex, Guadalope reef complex.
many other possibilities

Pinnacle of red strata exposed near Shell, Wyoming, near the joint Iowa State and University of Nebraska field camp on the west side of the Big Horn Mountains. What age are these strata? What were conditions like at the time they were being deposited? How are they related to underlying and overlying strata? These are some of the questions that stratigraphers and sedimentologists strive to answer. Also note that these sediments are being actively eroded, giving rise to modern sediments, which in turn will .....

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