Event Title

X-Ray Diffraction and Scanning Electron Microscope Fingerprinting of Regional Fine Sediment Sources

Location

CSU Ballroom

Start Date

16-4-2013 10:00 AM

End Date

16-4-2013 12:00 PM

Student's Major

Chemistry and Geology

Student's College

Science, Engineering and Technology

Mentor's Name

Chad Wittkop

Mentor's Department

Chemistry and Geology

Mentor's College

Science, Engineering and Technology

Description

Blue Earth Clay (BEC) is a bluish green siltstone sediment layer found locally and contained within the lower Cambrian-Ordovician boundary of geologic time. This siltstone plays a large part in the namesake of Blue Earth County. Historical outcrops have since eroded away and BEC exposures are now only known to be in a confined area west of Mankato, near South Bend, MN. Using the X-ray Diffractometer (XRD), local sediment sources have been sampled and analyzed for comparison with known BEC samples. The XRD produces a unique mineral structure fingerprint that can be used to assess relationships between fine sediment samples. These data are used to define possible BEC sediment sources and to explain the apparent regional restriction of this locally isolated sediment layer. Thus far, the BEC samples have been compared with samples from a local Cambro- Ordovician dolostone exposure. Removing the carbonate component of the dolostone before analysis allowed the XRD to detect finer sediment components. This was done to determine if the dolostone is a likely source material for the formation of regional siltstones including the BEC. Fine sediment layers found near the base of this dolostone exposure have also been analyzed with the XRD and have been compared to the mineral signatures found in the BEC. Preliminary data suggests similarities between BEC samples and dolostone-associated fine sediment suggesting common sources for the two independent sediment layers.

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Apr 16th, 10:00 AM Apr 16th, 12:00 PM

X-Ray Diffraction and Scanning Electron Microscope Fingerprinting of Regional Fine Sediment Sources

CSU Ballroom

Blue Earth Clay (BEC) is a bluish green siltstone sediment layer found locally and contained within the lower Cambrian-Ordovician boundary of geologic time. This siltstone plays a large part in the namesake of Blue Earth County. Historical outcrops have since eroded away and BEC exposures are now only known to be in a confined area west of Mankato, near South Bend, MN. Using the X-ray Diffractometer (XRD), local sediment sources have been sampled and analyzed for comparison with known BEC samples. The XRD produces a unique mineral structure fingerprint that can be used to assess relationships between fine sediment samples. These data are used to define possible BEC sediment sources and to explain the apparent regional restriction of this locally isolated sediment layer. Thus far, the BEC samples have been compared with samples from a local Cambro- Ordovician dolostone exposure. Removing the carbonate component of the dolostone before analysis allowed the XRD to detect finer sediment components. This was done to determine if the dolostone is a likely source material for the formation of regional siltstones including the BEC. Fine sediment layers found near the base of this dolostone exposure have also been analyzed with the XRD and have been compared to the mineral signatures found in the BEC. Preliminary data suggests similarities between BEC samples and dolostone-associated fine sediment suggesting common sources for the two independent sediment layers.

Recommended Citation

Bonney, Ryan. "X-Ray Diffraction and Scanning Electron Microscope Fingerprinting of Regional Fine Sediment Sources." Undergraduate Research Symposium, Mankato, MN, April 16, 2013.
http://cornerstone.lib.mnsu.edu/urs/2013/poster-session-A/35