Physical Geology lecture - Geologic resources and economic geology. Answers to questions.

What are major groups of geologic resources?

What are concentration processes that produce ore anomalies?

Image from USGS of hydrothermal circulation associated with Lassen Peak in California. Source - U.S. Geological Survey Fact Sheet 101-02 “Hot Water” in Lassen Volcano

These are sands from part of a beach face along Little Tybee Island in Georgia - note the oyster shells for scale. Quartz is one of the most common minerals in the beach sand here because it is mechanically touch and chemically stable. Most of the quartz is translucent to white. However, there are some 'heavy minerals' such as magnetite, ilmenite, monazite that when concentrated form ore deposits, some of which are rich in rare earth elements. The waves and wind do the sorting and under the right conditions take the lighter quartz sand away and leave the heavier minerals behind. The darker grains here are concentrated heavy minerals.


ic National Park— Fumaroles, Steaming Ground, and Boiling Mudpots: http://pubs.usgs.gov/fs/2002/fs101-02/.

What are the various types of geologic energy resources?

Image of surface oil shale extraction facility. From USGS site: http://energy.cr.usgs.gov/newsite/Templates/oilshaleindex.html

What are the geologic requirements for formation of oil and gas deposits?

How do we explore for oil and gas?

Example of a seismic section from the Mediterranean of the different layers, including a salt layer that has risen because of its bouyancy to form salt domes. Modern seismic imaging is much more powerful in its ability to image buried geologic features. Image from USGS site: http://pubs.usgs.gov/bul/b2204-a/b2204-a.html

Example of computer generated 3-D model based on seismic and drill-hole data. Image from USGS site: http://energy.er.usgs.gov/gg/research/modeling.html


How much water can the ground hold?

What are the physics of fluid flow through rocks?

This is a diagram of a Darcy's tube (basically a filter), which allows one to compute the hydraulic conductivity, which is one measure of intergrain permeability.

How does groundwater connect to the rest of the hydrologic cycle?


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