Physical Sciences and Mathematics Commons^™

Documenting The Anthropogenic Impact On Ballston Lake New York From A Short Core Using Stable Isotopes Of Carbon And Nitrogen And Trace Metals, Taylor S. Labrecque

Honors Theses

Ballston Lake occupies a portion of an avulsed channel of the Mohawk River between Schenectady and Saratoga Springs, New York. The lake is about 5 km long, generally less than 200m wide, ~8-15m deep, dimictic, with a catchment basin area of ~22km2. Long cores (>8 m) indicate that the lake formed ~13,000 cal yr BP. This study was undertaken to document recent environmental change recorded in the upper portion of sediment in Ballston Lake. Three sediment cores ~40 cm long were acquired from ~8 m water depth at the north end of Ballston Lake (42°57.101’N, 73°51.066’W), and were analyzed …

Glacial Lacustrine Records Of Holocene Climate Variations In The Tropical Peruvian Andes, Sasha Rothenberg

Honors Theses

Lake sediment cores taken from glacial lakes and wetlands are valuable proxies of glacial activity because they offer a continuous record of sediment input. Tropical alpine glaciers are especially sensitive to changes in precipitation and temperature, and thus the history of glaciation can be used in the reconstruction of past climates. Owing to a steep east-­‐to-­‐west moisture gradient across the Andes, glaciers in the eastern cordillera are more sensitive to changes in temperature whereas those in the drier, western, cordillera are more sensitive to changes in precipitation. Multiple lacustrine sediment cores were taken from two sites in the central Peruvian …

The History Of Mining In Cerro De Pasco And Heavy Metal Deposition In Lake Junin Peru, Erin M. Delman

Honors Theses

Lake Junín covers 530-km2 and is located at 4,430-m in an intermontane basin between the eastern and western cordillera of the central Peruvian Andes. The lake sits between the large sulfide mining districts of La Oroya and Cerro de Pasco. Designated a National Reserve in 1974, Lake Junín drains northward to the Río San Juan, which joins the Río Mantaro within several kilometers of the lake. Dam construction by the Cerro de Pasco Copper Corporation on the Río Mantaro in 1932 caused the Río San Juan, the principal river draining Cerro de Pasco, to back up into the lake. Using …

Mesoproterozoic Deposition, Regional Metamorphism And Deformation In North-Central New Mexico: Evidence From Metamorphic Monazite And Detrital Zircon Geochronology In The Picuris Mountains, Lily S. Pfeifer

Honors Theses

Detrital zircon and metamorphic monazite ages from the Picuris Mountains, north central New Mexico, were used to confirm the depositional age of the Marquenas Formation, to document the depositional age of the Vadito Group, and to constrain the timing of metamorphism and deformation in the region.

Detrital zircon 207Pb/206Pb ages were obtained with the LA-MC-ICPMS from quartzites collected from the type locality of the Marquenas Formation exposed at Cerro de las Marquenas, and from the lower Vadito Group in the southern and eastern Picuris Mountains. The Marquenas Formation sample yields 113 concordant ages including a Mesoproterozoic age population with four …

Sedimentology, Depositional Age, And Provenance Of Sedimentary And Volcanic Rocks Exposed Along Willow Creek, Eastern Susitna Basin, South-Central Alaska: Implications For Modification Of A Forearc Basin By Spreading Ridge Subduction, Erin E. Donaghy

Honors Theses

This is the first detailed study of the westernmost portion of the outcrop belt, which extends along the western flank of the Talkeetna Mountains and includes thick, well-exposed outcrops along Willow Creek in the eastern Susitna basin. New sedimentologic, compositional, and geochronologic data were obtained from stratigraphic sections within Arkose Ridge Formation strata at Willow Creek. This data combined with new geologic mapping and geochronologic data from Willow Bench and Kashwitna River Bluff (north of Willow Creek), and from the Government Peak area (east of Willow Creek), help constrain depositional processes and source terranes that provided detritus to the westernmost …

Geodynamic Constraints On The Flow Of Samoan-Plume Mantle Into The Northern Lau Basin, Nathan Katsiaficas

Honors Theses

The northernmost portion of the Lau basin, South Pacific, features numerous geochemical and geophysical anomalies. These include: (1) a strong latitudinal gradient in the trace element and isotopic (Sr-Nd-Pb) enrichment of basalts erupted along the various back-arc spreading centers (BASCs) within the basin, (2) high 3He/4He (up to 28 times RA, where RA, the ratio in Earth's atmosphere, is 1.4 x 10-6) in basalts erupted along some portions of the BASCs (e.g., Rochambeau Bank), and (3) the presence of trench-parallel shear-wave splitting near the Tonga arc. The occurrence of these anomalies has been attributed to the southward flow of mantle …

Examination Of Spatial Variations In Recrystallization Mechanisms In Quartz, Emma N. Beck

Honors Theses

S-C mylonites form as a result of non-coaxial deformation in ductile shear zones. Planes of weakness develop and delineate two domains, the S and the C Each of these domains accommodates variable amounts of strain. Sample WMSZ-188 exhibits subgrain rotation (SGR) recrystallization in the C domains, and grain boundary migration (GBM) recrystallization in the S domains. This partitioning of recrystallization mechanisms indicates either: (1) strain-rate partitioning during a single deformation event; or (2) a second, lower-temperature deformation event that over-printed the C domains. This study tests these two hypotheses. Optical and EBSD analyses were used to look for evidence of …