AMY HILLIS

Advisor: Karl Wirth
Senior Honors Thesis: 2012

Chemical Evolution of Intercumulus Liquid as Recorded in Plagioclase Overgrowth Rims from the Bald Eagle Intrusion, Northeast Minnesota

The Bald Eagle Intrusion in Northeast Minnesota is currently the subject of a copper-nickel-platinum group element sulfide exploration program by Duluth Metals, LLC. However, due to poor surface exposure, the geometry and magmatic evolution of this body are still poorly understood. This study attempts to understand the evolution of the magma chamber, particularly the final stages of crystallization, by investigating compositional zoning in plagioclase overgrowth rims. An understanding of the magmatic evolution of this body will aid exploration geologists in constraining the development of sulfide mineralization.

JANSEN SMITH

Advisor: Raymond Rogers
Senior Honors Thesis: 2012

Confamilial Predation on Naticid Gastropds through a Pulsed Extinction in the Plio-Pleistocene of the Carolinas

During the Plio-Pleistocene, a two-pulsed extinction occured among western Atlantic mollusks. Although taxonomic turnover related to the extinctions has been explored, accompanying ecological effects have remained largely unstudied. This study examines the effects of the turnover episodes on confamilial predation in shell-drilling naticid gastropods, an easily quantified predator-prey interation that is well preserved in the fossil record. Unstandardized drilling frequency rankings of alternative prey for two localities from each lithological unit show an abundance of alternative prey pre- and post-extinction. These rankings were size standardized used geometric mean to account for frequency on alternative prey genera remained higher than on naticid genera at five of six naticids was not caused by a decrease in alternative prey, but instead reflects a lower risk environment.

NORA HENCIR

Advisor: Colin Robbins
Senior Honors Thesis: 2012

Investigating Soil Mineralogic Controls of Las Vegas Buckwheat, Mojave Desert, USA

The Las Vegas Buckwheat is a threatened plant species from the Mojave Desert in the southwestern USA.  Although much of the desert appears to be viable buckwheat habitat, the plant has been found only in certain areas.  Soil samples from both inside and outside buckwheat habitat were analyzed to investigate two possible controls on buckwheat growth.  Phyllosilicate mineralogy was examined using x-ray diffraction and plant-available iron was investigated using x-ray fluorescence spectrometry.  While neither phyllosilicate mineralogy nor iron content appears to be the sole deciding factor, both may have roles to play in the complex problem of buckwheat habitat viability.

Read the project on Digital Commons

MADELINE MARSHALL

Advisor: Raymond Rogers
Senior Honors Thesis: 2012

Exceptional Record of Lungfish Burrows from the Upper Cretaceous Maevarano Formation, Mahajanga Basin, Northwester Madagascar

A large assemblage of lungfish aestivation burrows is documented from the Upper Cretaceous (Maastrichtian) Maevarano Formation of northwestern Madagascar.  These burrows demonstrate that lungfish were present in the Maevarano paleofauna, and they are the first lungfish aestivation burrows described from the rock record of Gondwana.  Over 100 large-diameter burrows penetrate a pervasively cross-stratified fluvial sandstone body intercalated near the top of the Masorobe Member.  Burrows cut through and deform surrounding foreset laminae, and in map view, the burrows exhibit three distinctive morphologies: circular, elliptical, and figure eight shaped.  These three map view cross-sections are identical matches with the modern burrow morphology of the African lungfish Protopterus when its burrow is exhumed along its full vertical expanse.  Combined, these cross-section views provide unequivocal indication of lungfish aestivation, and they are supplemented by several additional key characteristics, including spatial clustering (reflecting gregarious behavior), fin traces, and oxidized burrow margins.  The localized occurrence of 100+ lungfish aestivation burrows is consistent with previous reconstructions that posit a markedly seasonal dryland paleoenvironment for the Maevarano Formation.  

KAREN KISER

Advisor: Kelly MacGregor
Senior Honors Thesis: 2012

Glacial History of the Upper Esopus Drainage Basin, Catskill Mountains, New York

New York City drinking water is partially sourced through the Ashokan Reservoir located in the Upper Esopus drainage basin in the south-central Catskill Mountains, NY.  Fine sediment sources such as varved lacustrine clays and clay-rich tills are contributing to the suspended sediment load of the watershed, one of the main components in diminishing water quality. Students of the 2011 SUNY New Paltz REU program, in collaboration with the New York City Department of Environmental Protection, conducted field sampling and mapping as a means of estimating the extent of the fine sediment sources. GIS was utilized to model Pleistocene behavior.  Modeled glacial lacustrine extents were field checked to assess model predictions.  At some sites, a red diamict facies consisting of a compact clay-rich matrix and small pebbles overlies the lacustrine deposits.  Where observed, the contact shows extensive deformation that includes folded lake clays and silts with thrust faults.  This facies is interpreted as the basal facies of the overlying red till on valley floors.  The red till records an ice advance across valley floors covered with lake deposits.  A clay mineralogy analysis showed illite and chlorite present in all samples with the relative abundance of the two matching for the upper till, diamict, and lacustrine units and varying for the lower till unit, supporting the hypothesis of glaciers overriding pre-existing lakes.