Student research 1 of 3:
Title: Geoarcheology at Thomas Jefferson's Poplar Forest
Makenzie Hatfield '12 is working on an anthropology senior honors thesis that is attempting to create and refine an analytical technique that would allow for the use of minor variations in soil composition to determine the original locations of ornamental tree plantings at Thomas Jefferson's Poplar Forest estate (outside of Lynchburg, VA). The initial part of Makenzie's project (currently under way) will test whether a handheld XRF (Brucker Tracer III-V) that was recently acquired by the W&L Chemistry Department can be used to distinguish between areas augmented (fertilized) of soil that was part of transplanted root bulbs from Jefferson's nursery and the surrounding unfertilized soil. Our colleagues in the Archeology Department claim that Jefferson's use of fertilizer (including plaster) has been well-documented and so we are looking for subtle positive anomalies in P and S in the areas where trees plantings were suspected. Additional information at: http://geology.wlu.edu/low/EGC.html#poplar
37°20'52.59" N 79°15'52.41" W
Thomas Jefferson's Poplar Forest as viewed in Google Earth facing NNW. Aerial photo taken April 6, 2011 shows a tarp-covered excavation pit to the left of the main building.
Title: Xenoliths in the Western Grand Canyon
Natalie Stier '12 and Lauren Schultz '13 have been assisting Prof. Low with the study of xenoliths from three relatively (by geology standards) recent lava flows in the Western Grand Canyon. While these volcanoes and the bulk of their eruptive materials (a rock type called basalt that is relatively common at the Earth's surface) are certainly very interesting on their own, their flows also contain a variety of xenoliths, rock fragments that are torn loose from the walls of magma conduits and transported to the Earth's surface during eruption. Initial investigation into these xenoliths5 suggests that some originated in the middle of the Earth's crust and that some originated in the compositionally and mechanically distinct layer that underlies the crust known as Earth's mantle. Xenoliths such as these provide a rare opportunity for direct observation of materials from depths that are far too great for scientific drilling. The study of xenoliths can provide insight into the chemical composition of the materials and physical conditions deep within the crust and in the mantle and into the complex chemical and physical interaction between the mantle and crust. Xenoliths can also provide physical constrains upon magma movement beneath volcanoes. Additional information at http://geology.wlu.edu/low/xenos.html
36°11'52.15" N 113°09'56.34" W
Early morning in North Canyon well upstream from Lava Falls. Photo by C. Howard Capito '68
Student research 3 of 3:
Title: Holcomb Rock Dam Pluton
Maya Reimi '12 has been assisting with a geochemical and textural study of "Holcomb Rock," a sprawling outcrop and cliffscape next to the James River in the Blue Ridge Mountains of Virginia. This outcrop exhibits relatively well-preserved, large primary igneous minerals and complex but easily visible lithologic relationships between a variety of rock types and structures. Though the texture (size and shape of the rocks constituent minerals) at Holcomb Rock is distinct from other described mapped units in the area, this quadrangle has not been mapped at greater detail than is available in the state geologic map at 1:500,000 scale. The primary purpose of this project is to use evidence from rock and mineral compositions and textures to gain insight into the relationships between the different rock types present at the Holcomb Rock outcrop with the end goal of better understanding the history and dynamics of the magma chamber that crystallized to produce such interesting rocks. The secondary goal of the project is to apply this information, along with age constraints on crystallization and (possibly) subsequent metamorphism, to the complex tectonic history of the area. Additional information http://geology.wlu.edu/low/HRDP.html
37°30'39.20" N 79°15'56.35"W
Holcomb Rock Dam in the fall is just upstream from the major exposure of the pluton. Photo Steele Burrow ‘13
More Local Geology!!!