The Relationship Between Geology and Soil
Download
1 / 17

The Relationship Between Geology and Soil Development in Austin, Texas - PowerPoint PPT Presentation


  • 84 Views
  • Uploaded on

The Relationship Between Geology and Soil Development in Austin, Texas. Rob Forkner. Map courtesy of Sue Hvorka, BEG. Mt. Bonnell Fault. View from the top of Mt. Bonnell. Outcrop of the Glen Rose Limestone at Mt. Bonnell. Skimpy soil at Mt. Bonnell.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'The Relationship Between Geology and Soil Development in Austin, Texas' - ama


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

The Relationship Between Geology and Soil

Development in Austin, Texas

Rob Forkner








VS.

Inceptisol

Vertisol

Images from USDA


Shrink/Swell factor in Austin Soils

Shrink/Swell in soil is a function

of seasonality (wet/dry) and

amount of illitic clay within the soil

matrix.

Map from STATSGO, TX statewide

Soil data.



How can we use spatial analysis to determine

a more quantitative relationship

between soils and bedrock?

  • Rasterize data so that spatial analyst can work with it.

  • Reclassify data into groups of similar erodability.

  • Assign weights to erodability groups:

  • higher weight = more erodable

  • 4) Add raster layers to determine combined erodability.

Method Developed by Dr. Mark Helper, UT DOGS


Rasterized geological map with geological units grouped into formations.

Reclassified geological map with

formations classified into erodability

groups. More resistant rocks have

lower erodability. Limestone=1, Marl=2

Alluvium=3


Slopes on Austin West DEM formations.

reclassified into 4 groups with 20 degree increments. Steeper slopes are “colder”.

1-20 deg=1; 21-40 deg=2, etc.

Slope calculation applied to

Austin West DEM


Annual precip for Austin, 2001. Map from NRCS/USDA formations.

Brown area gets 1-1.5 inches more precip. per year.

For erosion weighting, Blue area = 1, brown area = 2


The Combination… formations.

Geology- Limestone = 1; Marl = 2; Alluvium = 3

Slope- 0-20 deg. = 1; 21-40 deg. = 2; 41-60 deg. = 3

60-80 deg. = 4

Precipitation- Most of the map = 1 (appx. 31”); with a small

area in the southeast being 2 (appx. 33”)


VIOLA! Sum of Raster Data formations.

Calculation of “erodability”

as a function of bedrock,

precipitation, and slope.

darker areas are more readily

erodable.

In general, rock on the upthrown

side of the fault is less erodable

than the rock on the downthrown

side.


What s next
What’s Next? formations.

  • Add a erodability parameter for vegetation cover and soil

  • Be more quantifiable with parameters for rock


ad