Geology LITE: Just How Does A Geologist’s Brain Work?

What do you see when you look at these mountains?

This road cut photo was taken in New Zealand.

Here’s a glimpse of how a Geologist might interpret the chain of events leading up to this picture:

• Deposition of sediment, predominantly sand (just guessing from what we can see in this picture, and without the benefit of examining these rocks). The older rocks are found on the bottom of this sequence. The variation in color would indicate a change in the environment of deposition, maybe from a beach ridge (light tan-colored beds) to a mucky swamp (darker brown colored units). It is interesting to note that the same color change (light tan to dark brown) occurred on several occasions. Some of these variations look to be more gradational, while others are sharp contrasts, which could indicate a period of non-deposition or erosion (a disconformity).
• The sediments are turned into rocks through processes called lithification and diagenesis. These sedimentary rocks were most likely made under conditions of low pressure and temperature, without significant alteration to their mineralogy and texture.
• The beds were cohesively uplifted to a new and higher elevation. It would appear that erosion occurred at land surface at the time of the uplift.
• A “normal fault” occurred, with the hanging wall (on the left) moving downward relative to the footwall. The normal fault is considered one of extensional movement (i.e., the two fault blocks moved away from each other). This faulting could have occurred before, at the same time as, or after the uplifting event.
• The road cut was made by man, creating the dramatic and spectacular scenery that Geologist go goo-goo gaa-gaa over.

The Question: What geologic features would enjoy reading more about here at I’m Just Thinkin’? Please leave your comments by clicking here.

The Geology LITE series is a light-hearted view of just about anything related to the earth. You can check out the other posts in this series by clicking here.