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beehaikui’m presenting an introduction to my research in two hours and i wish i could post the poster i made but i try to keep my location offline, so some of the info about the outcrop location is a little sensitive for a public blog. but anyway, here’s the basics!
i’m looking at two shale outcrops, one on the north side of a highway cut and the other on the south side. although the two are one continuous facies, the shale is about six meters thinner on the north side. this could be explained one of two ways;
1. the shale was eroded by a channel formed in the overlying sandstone, taking off the top 6 m, or
2. the shale on the north side was deposited much more slowly than the shale on the south side and the sandstone filled the resulting topographic low.
to figure out which is more likely, i’m taking a measured section in 10 cm intervals and analyzing gamma radiation, magnetic susceptibility, and x ray fluorescence to correlate the sections at a small scale. i’m looking for either gaps in the record on the north side, which would indicate erosion, or a compression of the signals i’m picking up (also on the north side), which would indicate slower deposition.
this is a pretty good starting point for analyzing the paleoenvironment. we know this region was a deltaic valley with a lot of moving water, but determining erosion levels and deposition rates on such a small scale allows for further analysis of the environment. my shale also extends throughout a large area of the US, so it would be helpful to have very specific data for one section that could be used as background for analyzing other areas. additionally, applying chemostratigraphy here sets up the possibility of correlating with distant outcrops by comparing chemostratigraphic results (basically, i’m contributing to the record of information we have on the facies which can be applied on a facies-wide scale).
i’m looking at two shale outcrops, one on the north side of a highway cut and the other on the south side. although the two are one continuous facies, the shale is about six meters thinner on the north side. this could be explained one of two ways;
1. the shale was eroded by a channel formed in the overlying sandstone, taking off the top 6 m, or
2. the shale on the north side was deposited much more slowly than the shale on the south side and the sandstone filled the resulting topographic low.
to figure out which is more likely, i’m taking a measured section in 10 cm intervals and analyzing gamma radiation, magnetic susceptibility, and x ray fluorescence to correlate the sections at a small scale. i’m looking for either gaps in the record on the north side, which would indicate erosion, or a compression of the signals i’m picking up (also on the north side), which would indicate slower deposition.
this is a pretty good starting point for analyzing the paleoenvironment. we know this region was a deltaic valley with a lot of moving water, but determining erosion levels and deposition rates on such a small scale allows for further analysis of the environment. my shale also extends throughout a large area of the US, so it would be helpful to have very specific data for one section that could be used as background for analyzing other areas. additionally, applying chemostratigraphy here sets up the possibility of correlating with distant outcrops by comparing chemostratigraphic results (basically, i’m contributing to the record of information we have on the facies which can be applied on a facies-wide scale).
