Physical Sciences and Mathematics Commons^™

Early Permian Seawater From The Delta18o Record Of Fossil Bivalves: Seasonality And A Latitudinal Gradient, James Andrew Beard

Earth & Environmental Sciences - Theses

The transition from a glaciated world to one that was ice-free makes the early Permian a time interval that in many ways mirrors the present, and hence there is great interest in constraining paleoclimate conditions over that transition. A common method for estimating ancient temperatures uses the oxygen isotope composition of marine carbonate, but this approach becomes significantly more complicated prior to the Cretaceous due to uncertainties about diagenesis and the isotopic composition of seawater, which has been hypothesized to be more depleted than during the Cenozoic. I use stable isotope compositions of sequentially microsampled accretionary calcite from fossil bivalves …

Geochemical And 40ar/39ar Constraints On The Evolution Of Volcanism In The Woodlark Rift, Papua New Guinea, Joseph Paul Catalano

Earth & Environmental Sciences - Theses

The tectonic mechanisms producing Pliocene to active volcanism in eastern Papua New Guinea (PNG) have been debated for decades . In order to assess mechanisms that produce volcanism in the Woodlark Rift, we evaluate the evolution of volcanism in eastern PNG using 40Ar/39Ar thermochronology and whole rock geochemistry.

Active volcanism in southeastern Papua New Guinea occurs on the Papuan Peninsula (Mt. Lamington, Mt. Victory and Waiwa), in the Woodlark Rift (Dobu Island, SE Goodenough Island, and Western Fergusson Island), and in the Woodlark Basin . In the Woodlark Basin, seafloor spreading is active and decompression melting of the upper mantle …

Investigating The Utility Of Detrital Mineral Microchemistry And Radiogenic Isotope Compositions As Provenance Discriminators, Jack Hietpas

Earth & Environmental Sciences - Dissertations

The provenance of clastic sediments remains one of the key tools for understanding the complex dynamic history of the Earth. Detritus shed from ancient orogens may be the only evidence available for determining the timing, evolution, paleogeography, and existence of tectonic events active over the 4.56 Ga of Earth history. The focus of this dissertation research is to assess the strengths and limitations of existing, as well as novel, tools for determining the provenance of siliciclastic sediments.

The utility of detrital monazite crystallization ages was investigated as a provenance indicator in both modern and ancient sedimentary systems. The results from …

Using Emerging Methods To Investigate Stream And Groundwater Interaction At Multiple Spatial Scales, Martin Ashley Briggs

Earth & Environmental Sciences - Dissertations

Fundamentally, streams represent physical conduits of water across gradients, yet a more holistic definition reveals stream corridors support a mosaic of living communities in a blend of surface and ground waters. The physical and biogeochemical patterns these dynamic systems support affect natural habitat and water quality, directly impacting the human experience. Our understanding of stream and groundwater interactions is at a time of rapid expansion due to an increase in environmental awareness, accountability, and emerging techniques which can be used to decipher underlying controls and develop predictive relationships. Water temperature has been used as a qualitative environmental tracer during the …

The Role Of Magmatism In The Catalina Metamorphic Core Complex, Arizona: Insights From Integrated Thermochronology, Gravity And Aeromagnetic Data, Jessica Terrien

Earth & Environmental Sciences - Dissertations

The footwall of the Catalina MCC located within the Basin and Range Province has been intruded by several magmatic suites. Samples were collected from the Wilderness suite sills, the most voluminous suite. U/Pb data from zircon indicate that the Wilderness suite sills were emplaced during two separate phases of magmatism, the first at ~55 Ma and the second at ~45 Ma with additional evidence of zircon growth at <40 Ma.

40Ar/39Ar data from the Wilderness suite sills indicate that the majority of the older 40Ar/39Ar apparent ages from both potassium feldspar and mica were obtained from the structurally higher sills in the …

Geochemical And Geochronological Constraints On The Origin And Evolution Of Rocks In The Active Woodlark Rift Of Papua New Guinea, Nasser Alexander Zirakparvar

Earth & Environmental Sciences - Dissertations

Tectonically active regions provide important natural laboratories to glean information that is applicable to developing a better understanding of the geologic record. One such area of the World is Papua New Guinea, much of which is situated in an active and transient plate boundary zone. The focus of this PhD research is to develop a better understanding of rocks in the active Woodlark Rift, situated in Papua New Guinea's southernmost reaches. In this region, rifting and lithospheric rupture is occurring within a former subduction complex where there is a history of continental subduction and (U)HP metamorphism. The lithostratigraphic units exposed …