WorldCat Identities

Princeton University Department of Geosciences

Overview
Works: 47 works in 48 publications in 1 language and 71 library holdings
Genres: Academic theses 
Roles: Researcher
Classifications: GC117.C37,
Publication Timeline
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Most widely held works by Princeton University
Reduction and Re-oxidation of Soils During and After Uranium Bioremediation; Implications for Long Term Uraninite Stability and Bioremediation Scheme Implementation( )

1 edition published in 2006 in English and held by 6 WorldCat member libraries worldwide

This research focuses on the conditions and rates under which uranium will be remobilized via oxidation after it has been reduced and precipitated biologically, and what factors can contribute to increasing its long-term stability in groundwater after the injection of an electron donor has been discontinued
Global Ocean Data Analysis Project (GLODAP) : results and data( Book )

1 edition published in 2005 in English and held by 3 WorldCat member libraries worldwide

Seismic imaging and inversion based on spectral-element and adjoint methods by Yang Luo( Book )

1 edition published in 2012 in English and held by 2 WorldCat member libraries worldwide

In this dissertation, we focus on solving these remaining issues in adjoint tomography, from a theoretical perspective and based upon synthetic examples. To make the thesis complete by itself and easy to follow, we start from development of the spectral-element method, a wave equation solver that enables access to accurate synthetic seismograms for an arbitrary Earth model, and the adjoint method, which provides Frechet derivatives, also named as sensitivity kernels, of a given misfit function. Then, the sensitivity kernels for waveform misfit functions are illustrated, using examples from exploration seismology, in other words, for migration purposes. Next, we show step by step how these gradient derivatives may be utilized in minimizing the misfit function, which leads to iterative refinements on the Earth model. Strategies needed to speed up the inversion, ensure convergence and improve resolution, e.g., preconditioning, quasi-Newton methods, multi-scale measurements and combination of traveltime and waveform misfit functions, are discussed. Through comparisons between the adjoint tomography and classical tomography, we address the resolution issue by calculating the point-spread function, the action of the Hessian on an arbitrarily-chosen model perturbation, and the resolution function, the action of the resolution matrix on the arbitrarily-chosen model perturbation. Inner products between the two functions and the chosen model perturbation (properly normalized) are two scalars--the point-spread parameter and the resolution parameter. The two functions serve as trade-off maps between the chosen model perturbation and all other model parameters, whereas the two parameters indicate whether the chosen model perturbation is well resolved in the inversion. While the point-spread function and the point-spread parameter work in relative sense, the resolution function and the resolution parameter are absolute quantities, regardless of the misfit function used in the inversion. Besides the optimization point of view, we also treat inverse problems from Tarantola's perspective--the Bayesian inference, where each Earth model is associated with certain probability, preferably obeying multivariate normal distribution by choosing Cartesian model parameters, such as the logarithm of wavespeed. With a new limit-memory square root variable metric algorithm, we may sample the a posteriori distribution of model parameters, which allows statistical analysis on the inversion, e.g., addressing uncertainty and non-uniqueness of the inversion. Although, due to limit of time, seismic examples are to be added, analytical examples involving 20,000 model parameters validate our theory and algorithm, and it is promising that they can be easily adapted to real seismic applications. After solving both resolution and non-uniqueness issues, we finally extend capability of seismic inversions to consider noise simulations, i.e., by cross correlating noisy seismograms between pairs of seismic stations, without help of natural earthquakes and man-made explosions. At the end, we talk about implications of our studies on the model parameterization, in terms of both types of model parameters, partially mentioned throughout all chapters, and (spatial) basis functions for each type of model parameters, where wavelet/curvelet bases or kernel-driven bases might be used
Studies of the oxygen and carbon cycles in the surface ocean by Sheng Huang( Book )

1 edition published in 2013 in English and held by 2 WorldCat member libraries worldwide

The thesis work consists of two projects that study carbon and oxygen cycles in the surface ocean. In the first project, net community O2 production (NCP) and gross primary O2 production (GPP) were estimated using [O2]/[Ar] ratios and the triple isotope composition of dissolved O2 in samples collected during 4 consecutive January cruises from 2008-2011 in the West Antarctica Peninsula (WAP) region of the Southern Ocean. Our study indicates large spatial and interannual variability of NCP and GPP, and suggests that light and iron are the most important factors that regulate NCP and GPP in the study region. While light availability is controlled by the surface irradiance and the mixed layer depth (MLD), iron could be largely regulated by deep winter mixing that supplies iron from the deep water. The relationships between NCP (NCP/GPP) and a number of physical properties implies that NCP is positively correlated with the strength of deep winter mixing. The deep mixing could be weakened when increasing heat content in the ocean and increasing air temperature inhibit sea ice growth and winter water formation. Overall, our study indicates that ocean productivity tends to decrease in the study region in response to changes in physical conditions associated with rapid warming in this region. In the second project, an automatic system using isotope dilution as its core method has been developed to obtain high-frequency measurements of dissolved inorganic carbon concentration ([DIC]) in the surface ocean. This system accurately mixes seawater samples and a NaH13CO3 solution. The mixed solution is acidified and sent through a gas permeable membrane contactor. CO2 derived from DIC in the mixture is extracted and sent to a cavity ringdown spectrometer to for 13C/12C analysis. [DIC] of the seawater can be calculated from the measured 13C/12C, the known mixing ratio and the [NaH13CO3]. The method has been tested in the laboratory and on a cruise. At 15 samples/hour, the precision and the accuracy of the method are <0.1 %. Results of these tests indicate that the method can provide accurate shipboard [DIC] measurements at high resolution in most oceanic regions
Portrait of a Pluton: Magmatic Perspectives from the Mid-Crustal Bergell Intrusion, Central Alps by Kyle M Samperton( Book )

1 edition published in 2017 in English and held by 2 WorldCat member libraries worldwide

The study of Earth is an inherently historical scientific enterprise. Geochronology, i.e., the science of determining the ages of rocks and minerals, the dates of geologic events, and the durations or tempos of naturally-occurring phenomena, is therefore essential to the de- velopment of holistic models of Earth system processes. Uncertainties persist as to the characteristic rates and mechanisms of magma transport, differentiation and cooling in the crust, with direct implications for the spatiotemporal scales of magma chambers, degree of crustal compositional stratification, and processes of volcanism. Debate is also ongo- ing as how to best apply geochronological methods to better constrain igneous phenomena. Chapter 1 provides an introduction to geochronology; the status of geochronology both as a tool and a discipline in and of itself; and the application of geochronological methods to problems in igneous petrology. Chapter 2 introduces a multi-method geochronological-- geochemical workflow for precise characterization of the "gold standard" geologic timekeeper, the mineral zircon. This workflow is applied to the Bergell Intrusion, a tilted mid-crustal magmatic system exposed in the Swiss-Italian Alps, with temporal trends in zircon com- position indicating protracted magmatism in the deep crust. Chapter 3 bridges Bergell zircon age--temperature--compositional spectra with thermodynamic and diffusive models of zircon crystallization, highlighting to an unprecedented degree zircon's capacity as a tracer of magma evolution. Chapter 4 presents the results of original field mapping, structural analysis and titanite thermochronology across a range of magma emplacement depths, es- tablishing a comprehensive framework for modeling Bergell assembly. Chapter 5 synthesizes the preceding findings in the form of a numerical model that describes the emplacement and thermal evolution of the Bergell, with field, structural and geochronological data incorpo- rated as model constraints. Cumulatively, this contribution details the history of a dynamic, long-lived, incrementally-assembled intrusive suite, and provides a template for innovative application and interpretation of geochronological data in future studies
Seismic structure of the European crust and upper mantle based on adjoint tomography by Hejun Zhu( Book )

1 edition published in 2013 in English and held by 2 WorldCat member libraries worldwide

We use adjoint tomography to estimate three-dimensional variations in seismic parameters within the crust and upper mantle beneath Europe and the North Atlantic Ocean. Spectral-element and adjoint methods are used to numerically calculate synthetic seismograms and sensitivity kernels in three-dimensional Earth models. Combined with gradient- based optimization algorithms, e.g., preconditioned conjugate-gradient and L-BFGS methods, we iteratively update seismic models of Earth's interior. A three-stage inversion strategy is designed to estimate variations in elastic wavespeeds, anelastic attenuation and radial & azimuthal anisotropy. In stage one, frequency-dependent phase differences between observed and simulated seismograms are used to determine a new radially anisotropic wavespeed model for the European crust and upper mantle, namely EU30. Long-wavelength structures in EU30 compare favorably with previous body- and surface-wave tomographic models. Some hitherto unidentified features naturally emerge from the smooth starting model. In stage two, frequency-dependent amplitude differences combined with remaining phase anomalies are used to simultaneously constrain elastic and anelastic structures. A new anelastic model, named EU50, is constructed in this stage. We observe several notable features, such as enhanced attenuation within the mantle transition zone beneath the North Atlantic Ocean. In the first two stages, long-period surface waves and short-period body waves in three-component seismograms are combined to simultaneously constrain shallow and deep structures. In stage three, frequency-dependent phase and amplitude anomalies of three-component surface waves are used to construct a radially and azimuthally anisotropic model EU60. We find that the direction of the fast axis is closely tied to the tectonic evolution in this region, such as extension along the North Atlantic Ridge, trench retreat in the Mediterranean, and counterclockwise rotation of the Anatolian Plate. Radial peak-to- peak anisotropic strength profiles identify distinct brittle-ductile transitions in lithospheric strength beneath oceans and continents, in agreement with observations in mineral physics experiments
Physiological and environmental controls on the nitrogen and oxygen isotope fractionation of nitrate during its assimilation by marine phytoplankton by Kristen L Karsh( Book )

1 edition published in 2014 in English and held by 2 WorldCat member libraries worldwide

The N isotope effects for nitrate uptake and efflux, measured in the marine diatom Thalassiosira weissflogii, were low relative to that associated with reduction (2.0 +/- 0.3 / and 1.2 +/- 0.4permil, respectively). The ratio of O-to-N isotopic fractionation was greater than 1 for both processes (1.4 +/- 0.4 for uptake and 2.3 +/- 0.9 for efflux). Finally, whole cell N and O isotope effects were measured in continuous culture of T. weissflogii. The N isotope effect showed little variation (5.1 - 5.8permil) across a 4-fold change in growth rate under phosphate limitation. In contrast, under light limitation, the N isotope effect increased by a factor of 3 (to 17.5permil). Equivalent N and O isotope fractionation was observed under all conditions. In sum, these results validate the existing physiological model for isotopic fractionation during nitrate assimilation where intracellular reduction is the dominant fractionating step. They provide the first step in understanding the cellular basis for the equivalent fractionation of N and O associated with nitrate assimilation in the ocean. Results from this and previous studies suggest that (i) little variation in N isotope effect may be expected under most environmental conditions due to cellular control over the relative rates of steps in nitrate assimilation and (ii) irradiance may be the dominant driver of variability in the N isotope effect in the ocean
Bimaterial effects on earthquake source mechanics by Enning Wang( Book )

1 edition published in 2013 in English and held by 2 WorldCat member libraries worldwide

A material contrast exists on the San Andreas fault, with the Pacific plate to the SW more rigid than the North American plate to the NE. This thesis explores the effect of this material contrast on earthquake source mechanics. Two manifestations of the bimaterial effects in seismic observations are examined: 1. The existence of a systematic rupture propagation direction, and 2. Possible asymmetry in the distribution of immediate aftershocks. In the first study, rupture directivity is quantified using the rupture lengths in the NW and SE directions along the San Andreas fault, and the rupture lengths are determined using the ratios of the spectra between nearby earthquakes. The directivity of nearly 900 events in a 3000 event catalog are reasonably well resolved. & sim;40% of these events are roughly bilateral, although more than & sim;80% of the 144 events classified as strongly unilateral rupture to the SE. The well-resolved rupture speed to the SE is also greater by roughly 10%. The preferential propagation to the SE is consistent with theoretical predictions. We also found that events with nearby foreshocks within several hours tend to rupture away from those foreshocks, indicating that asymmetry of prior stressing history can exert a stronger influence on rupture directivity than the material contrast. To study the possible asymmetry in the distribution of immediate aftershocks, we searched for compound earthquakes which consist of two subevents separated by less than 0.3 second. About 450 candidate compound events were identified on the northern San Andreas and part of the Calaveras fault. Most delays between the two subevents cluster around the shear-wave transit time over the subevent separation. For subevents on the San Andreas fault which are separated by 0.7 to 2 times the estimated radius of the first subevent, more than twice as many second subevents occurred to the SE of the first as to the NW. The asymmetry of second subevent distribution is not present on the Calaveras fault, which has no significant material contrast in this region. One interpretation is that the extra SE subevents on the San Andreas fault are representative of the events "missing" from the "longer term" (10s-9hrs) aftershock population because they became part of the mainshock
Tectonics, structure, and metamorphic evolution of the Himalayan fold-thrust belt, western Bhutan by Tobgay Tobgay( Book )

1 edition published in 2011 in English and held by 2 WorldCat member libraries worldwide

We divide the Lesser Himalayan (LH) section into four map units that range from Paleoproterozoic to Ordovician in age. The Paro Formation is interpreted as the distal equivalent of the Jaishidanda Formation based on a similar structural position immediately below the Main Central thrust (MCT) as well as similarity in detrital zircon signatures. Th-Pb ages of metamorphic monazite from Greater Himalayan (GH) rocks and a single age from the upper LH rocks bracket the minimum age of the MCT displacement between 20.4 +/- 1.0 and 15.1 +/- 0.4 Ma. Young monazite ages indicate that GH rocks continued to cool even until & sim;10 Ma. A total displacement of & sim;230 km achieved over 5 Myr yields a long-term horizontal shortening rate of 4.3 +/- 1.2 cm/yr
Nitrate Assimilation by Eukaryotic Phytoplankton as a Central Characteristic of Ocean Productivity by Sarah Elizabeth Fawcett( Book )

1 edition published in 2012 in English and held by 2 WorldCat member libraries worldwide

Throughout the year, the low 15N/14N of Prochlorococcus indicates reliance on recycled N. Synechoccocus 15N/14N also evinces recycled N consumption in the summer and fall, whereas in March, Synechoccocus 15N/14N was more variable and higher than Prochlorococcus, implying that Synechoccocus assimilates nitrate during springtime conditions of high availability
Comings and goings of the end-Cryogenian ice sheet: A stratigraphic study of the pre-, syn-, and post-glacial deposits, South Australia by Catherine V Rose( Book )

1 edition published in 2012 in English and held by 2 WorldCat member libraries worldwide

Glacial deposits generated during the Marinoan Glaciation have received little attention in recent years because research has emphasized the geochemistry of the pre- and post-glacial carbonate successions. However, these enigmatic low-latitude glacial sediments hold important information regarding the style of regional glaciation, as well as sedimentological details, that provide clues about global nature of the glaciation. The syn-glacial Elatina Fm records an impressive array of facies at different water depths across the ARC and provides a unique opportunity to study the comings and goings of a low-latitude ice sheet within South Australia. I present detailed sedimentological observations coupled with high-resolution geochemical data throughout the pre- and syn-glacial sediments of the Elatina glaciation to document the onset of the glaciation across the basin, quantify the degree of erosion, identify the provenance of sediment and clasts, and determine temporal variability in chemical weathering to test predictions of the snowball Earth model. This work provides the first geochemical analysis of the Elatina diamictites, reinterprets the sedimentary fold test for the low-latitude paleolatitude interpretation, and presents detrital zircon U-Pb ages data that may have implications for correlation of the Elatina glaciation to other low-latitude glacial deposits
Use of the nitrate isotopes in the ocean interior to explore the isotopic composition of sinking nitrogen and its implications for marine biogeochemical cycles by Dario Marconi( Book )

1 edition published in 2017 in English and held by 2 WorldCat member libraries worldwide

Chapter 4 reports and interprets nitrate isotope data along the CLIVAR A16N, a hydrographic section from south of Iceland to 6°S in the tropical Atlantic that provides a meridional view that is closely related to the largely north/south subsurface circulation of the Atlantic. Three approaches are used to calculate the delta15N of regenerated nitrate and of sinking N
Observations and Modeling of Temporal Variability in Slow Slip Events by Jessica Cleary Hawthorne( Book )

1 edition published in 2012 in English and held by 2 WorldCat member libraries worldwide

In the first observational component, we use borehole strain data to look for tidal variations in the slow slip moment rate in central Cascadia. We find that slow slip is tidally modulated. On average, the moment rate oscillates 25% above and below the mean at the period of the strongest tide. This modulation implies that slow slip is sensitive to small external stresses. It provides a useful constraint on models of slow slip events
The stable isotopic composition of dissolved organic nitrogen and nitrate in the subtropical ocean by Angela Noel Knapp( )

1 edition published in 2006 in English and held by 2 WorldCat member libraries worldwide

A study of the ocean's water masses using data and models by Yves Plancherel( Book )

1 edition published in 2012 in English and held by 2 WorldCat member libraries worldwide

One recurrent theme of the water mass synthesis presented here is that overflows, entrainment at the overflows, water mass formation and export is often impacted critically by small bathymetric features, such as the Maud Rise in the Weddell Sea, the Orphan Knoll in the Labrador Sea, the depth and width of continental shelves or the presence of canyons cutting through the shelf break. Mode and intermediate water formation are critically dependent on the winds and on the cycling of the mixed layer. Some water masses, such as Eastern Subtropical Mode Waters in the North Pacific, can also depend critically on peculiarities of the seasonal cycle of the buoyancy flux, making these waters an interesting potential early warning diagnostic for climate change. As water mass formation often requires cold winter air bursts, small zonal or meridional shifts in the winds can have a dramatic impact on the formation characteristics of water masses
Effects of iron enrichment on the chemistry and physical properties of deep lower mantle silicates by Susannah M Dorfman( Book )

1 edition published in 2012 in English and held by 2 WorldCat member libraries worldwide

Variations in seismic wave speed and density in the Earth's deep lower mantle have been linked to chemical heterogeneities. In order to identify the compositions of these regions and determine their roles in Earth history and dynamics, experimental measurements are needed of the effects of compositional variation, particularly major elements Fe and Al, on phase equilibria and physical properties of mantle minerals. The experiments that comprise this dissertation provide new constraints on the chemistry and compressibility of mantle silicates
Stratigraphic records of paleogeography and global change from two late Proterozoic basins by Nicholas L Swanson-Hysell( Book )

1 edition published in 2011 in English and held by 2 WorldCat member libraries worldwide

I report high-resolution paleomagnetic data in stratigraphic context from Mamainse Point, Ontario--the most complete succession in the 1.1 billion-year-old Mid-continent Rift. The results demonstrate that previous suggestions of large non-dipolar geomagnetic field components at the time stemmed from low temporal resolution across geomagnetic reversals during a period of rapid plate motion. This result strengthens the framework for evaluating records of tectonics and climate across the Mesoproterozoic/Neoproterozoic boundary. Rock magnetic experiments on Mamainse Point lavas, paired with electron microscopy, demonstrate that a component of the magnetization in oxidized flows that is antiparallel to the characteristic remanence is a result of martite self-reversal. This component is the best resolved natural example of the experimentally observed self-reversal that accompanies the maghemite to hematite transition. This result allows the magnetizations of the lavas to be fully interpreted, and also suggests that this self-reversal phenomena may be more widespread than currently recognized--with its identification in this study being greatly aided by stratigraphic context during a period when North America was moving rapidly towards the equator
Glacial/interglacial and deglacial changes in ocean circulation and their consequences for the global carbon cycle: A model study by Mathis P Hain( Book )

1 edition published in 2013 in English and held by 2 WorldCat member libraries worldwide

This dissertation documents model results that quantitatively address the physical, biological and chemical processes that caused the tight correspondence between the late Pleistocene glacial/interglacial climate cycles and concentration of atmospheric CO2. Central to most current hypotheses for the glacial/interglacial CO2 cycles is the ocean's "biological pump." To quantify the net contribution of distinct ocean changes to glacial CO 2 drawdown, and to identify the geochemical changes that determine these net CO2 sensitivities, new diagnostic tools are applied to CYCLOPS carbon cycle model. Based on this analysis, it is inferred that the punctuated saw tooth pattern of the CO2 cycles is best explained by the successive activation of Antarctic, Subantarctic and North Atlantic changes, and that much of the deep ice age ocean was ventilated from the North Atlantic. Due to the preservation of radiocarbon signatures, the last deglaciation offers additional constrains on the state of the glacial ocean, and helps to test hypotheses about ocean circulation changes and carbon redistribution. In this deglacial context, this dissertation presents the first attempt to simulate deglacial radiocarbon anomalies found in some sites of the Indo-Pacific, which have been taken as evidence for the popular hypothesis that the deep glacial ocean stagnated to become a reservoir for the sequestration of CO2 from the atmosphere, and that this reservoir of radiocarbon-deplete carbon was vented during deglaciation. These simulations render a uniquely isolated glacial deep ocean unlikely, and strongly argue that the radiocarbon anomalies record local processes rather than a basin-scale release of deep ocean carbon, such that two episodes of abrupt deglacial atmospheric 14C/C decline demand an alternative explanation. While accounting for the uncertainty in the history radiocarbon production, it is found that observations can be closely matched by deglacial model experiments, with abrupt 14C/C decline caused by the repeated initiation of North Atlantic Deep Water formation instead of Southern Ocean changes that release CO2 to the atmosphere. Overall, the competition between North Atlantic and Southern Ocean over the ventilation of the deep ocean found to be central to the ice age CO2 cycles mirrors the "bipolar seesaw" of warming and cooling among the hemispheres
An analysis of marine ecosystem dynamics through development of a coupled physical-biogeochemical-fisheries food web model by Kelly Anne Kearney( Book )

1 edition published in 2012 in English and held by 2 WorldCat member libraries worldwide

Over the past decade, fisheries management efforts have placed increased emphasis on ecosystem-based management, where the interactions between a target stock species and its physical and biological environment are considered in addition to sustainability of the stock itself. At the same time, global-scale climate models that historically focused only on physical and biogeochemical variables are increasingly incorporating biological variables. With these shifts, the historical separation between climate modeling and fisheries modeling is closing, with increased interest in the concept of end-to-end models, i.e. models that incorporate dynamics from physics to top predators
The effects of physical and biogeochemical changes on carbon emissions from mineral cryosols from the Canadian High Arctic by Brandon Stackhouse( Book )

1 edition published in 2016 in English and held by 1 WorldCat member library worldwide

The Arctic regions contain vast stores of organic carbon within the permafrost, isolated from the current global carbon cycle. Changes in global climate, however, are likely to place this carbon pool at risk of degradation as temperatures increase at high northern latitudes and the extent of continuous permafrost decreases. Changes in the temperature and hydrology of permafrost systems will affect total carbon loss from polar regions and the balance of CO 2 to CH4 emissions. This study examined how changes in Arctic mineral cryosols will extend to carbon emissions, geochemical conditions, and microbial community composition over time at Axel Heiberg Island, Nunavut, Canada
 
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