Image: Figure 1. Downhole borehole images, geochemistry, and geophysics. Optical borehole imager view of the borehole wall (A) and yellow hue, defined as (R + G)/2-B (B). Inclined planar features such as fractures appear as sinusoids on these unrolled 360° images of the borehole wall. Warm colors in (B represent higher levels of yellow and brown; cooler colors represent gray. Above 55 m depth, yellow/brown versus gray hues generally indicate weathered versus unweathered minerals, respectively; below 55 m, a different rock exists and yellow colors do not necessarily indicate weathering. Downhole geochemical and geophysical data demarcate the onset of weathering around 38 m depth (C–G), which corresponds with visual changes in A and B. [Click image to enlarge]
Steve Holbrook's paper using data from Calhoun's 65-meter borehole is out in Nature's Scientific Reports. The paper, largely about in situ weathering & soil formation of a textbook Southern Piedmont regolith, is co-authored by researchers across several CZOs, with Virginia Marcon and Susan Brantley of Shale Hills, and Brady Flinchum and Clifford S. Riebe of Sierra joining Calhoun's Allan Bacon and Dan Richter.
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Sierra, COLLABORATOR, GRAD STUDENT
Links between physical and chemical weathering inferred from a 65-m-deep borehole through Earth’s critical zone. Holbrook, W. Steven, Virginia Marcon, Allan R. Bacon, Susan L. Brantley, Bradley J. Carr, Brady A. Flinchum, Daniel D. Richter, & Clifford S. Riebe (2019): Scientific Reports 9: Article number 4495