Preprints
Filtering by Subject: Physical Sciences and Mathematics
The forearc ophiolites of California (USA) formed during trench-parallel spreading: kinematic reconstruction of the western USA Cordillera since the Jurassic
Published: 2022-11-01
Subjects: Physical Sciences and Mathematics
Ophiolites, fragments of oceanic lithosphere exposed on land, are typically found as isolated klippen in intensely deformed fold-thrust belts spanning hundreds to thousands of kilometers along-strike. Ophiolites whose geochemistry indicates that they formed above subduction zones, may have been relics of larger, once-coherent, oceanic lithosphere tracts that formed the leading edge of an upper [...]
The ice dynamic and melting response of Pine Island Ice Shelf to calving
Published: 2022-10-31
Subjects: Physical Sciences and Mathematics
Sea level rise contributions from Pine Island Glacier (PIG) are strongly modulated by the backstress that its floating extension – Pine Island Ice Shelf (PIIS) – exerts on the adjoining grounded ice. The front of PIIS has recently retreated significantly via calving, and satellite and theoretical analyses have suggested further retreat is inevitable. As well as inducing an instantaneous increase [...]
Strategies for making geoscience PhD recruitment more equitable
Published: 2022-10-28
Subjects: Earth Sciences, Education, Outdoor Education, Physical Sciences and Mathematics
Doctoral study is a crucial part of the academic pipeline, but discriminatory admissions procedures disproportionately impact students from ethnic minority backgrounds. We examine how doctoral recruitment policies contribute to inequity in the geosciences and propose improvements for change.
Quantitative constraints on flood variability in the rock record.
Published: 2022-10-27
Subjects: Earth Sciences, Physical Sciences and Mathematics
Floods determine river behaviour in time and space. Yet quantitative measures of discharge variability from geological stratigraphy are sparse, even though they are critical to understand landscape sensitivity to past and future environmental change. Here we show how storm-driven river floods in the geologic past can be quantified, using Carboniferous stratigraphy as an exemplar. The geometries [...]
Reconciling the Cretaceous breakup and demise of the Phoenix Plate with East Gondwana orogenesis in New Zealand
Published: 2022-10-27
Subjects: Physical Sciences and Mathematics
Following hundreds of millions of years of subduction in all circum-Pacific margins, the Pacific Plate started to share a mid-ocean ridge connection with continental Antarctica during a Late Cretaceous south Pacific plate reorganization. This reorganization was associated with the cessation of subduction of the remnants of the Phoenix Plate along the Zealandia margin of East Gondwana, but [...]
Experimental comparisons of carbonate-associated sulfate extraction methods
Published: 2022-10-26
Subjects: Biogeochemistry, Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics
Carbonate-associated sulfate (CAS) refers to trace amounts of sulfate incorporated into carbonate minerals during precipitation. CAS has been the most commonly used approach to recover the paleo-seawater sulfate sulfur isotope composition (δ34Ssw) as carbonate rocks are more common and occur in less restricted marine environments than alternative sulfate-bearing minerals (such as gypsum and [...]
A decade of in situ cosmogenic 14C in Antarctica
Published: 2022-10-26
Subjects: Physical Sciences and Mathematics
Cosmogenic nuclide measurements in glacial deposits extend our knowledge of glacier chronologies beyond the observational record. The short half-life of in situ cosmogenic 14C makes it particularly useful for studying glacier chronologies, as resulting exposure ages are less sensitive to nuclide inheritance when compared with more commonly measured, long-lived nuclides. An increasing number [...]
Restricted rupture evolution of the 2022 Mw 6.7 Luding China earthquake
Published: 2022-10-25
Subjects: Earth Sciences, Physical Sciences and Mathematics
On September 5, 2022, a strike-slip earthquake with a moment magnitude (Mw) 6.7 occurred along the Moxi segment of the Xianshuihe fault zone in Luding, Sichuan province, China. To estimate the rupture evolution of the 2022 Luding earthquake, we inverted teleseismic P-waves by applying the Potency Density Tensor Inversion, a novel method that can estimate fault geometry and source process. We [...]
Sedimentological Characteristics, and Provenance of the Late Cretaceous Sediment in the Eastern Dahomey Basin
Published: 2022-10-24
Subjects: Physical Sciences and Mathematics
Field studies of outcrop samples from part of the Dahomey basin, southeastern Nigeria, were investigated to unravel the lithofacies distribution and provenance of the basin. Granulometric analysis of the sandstone facies of the Araromi Formation has been studied. Histograms of the sediments exhibit both unimodal and bimodal trends. The cumulative curve of the studied samples Is typical of fluvial [...]
GEOCHEMICAL AND MINERALOGICAL STUDY OF THE CRETACEOUS SEDIMENTS IN KERI KERI, FIKA, GONGILA, AND BIMA SANDSTONE FORMATION BORNU BASIN, NORTH-EASTERN NIGERIA
Published: 2022-10-24
Subjects: Physical Sciences and Mathematics
The mineralogical and geochemical composition of Cretaceous and Tertiary sediments of the Bornu Basin, northeastern Nigeria penetrated by Kanadi Wells, have been studied towards deducing aspects of their derivation and deposition. The sediments comprising the Bima Sandstone Formation, sandy-shale Gongila Formation, and, clayey and shaley Fika Formation are mainly composed of quartz (35-58%) and [...]
GEOCHEMICAL SURVEY AND POTENTIAL MINERALIZATION INVESTIGATION OF ILERO AND ITS ENVIRONS OYO STATE, NIGERIA
Published: 2022-10-24
Subjects: Physical Sciences and Mathematics
Ilero and its environs are part of the Kajola local Government area, Oyo State, and fall within the basement complex of southwestern Nigeria. The research work was focused on the geological mapping of the area and the study of the different rock and minerals units to determine the mineral resources of the area using petrographic, geochemical, and XRD analysis. The geochemical analysis showed the [...]
SHALLOW COMPOSITION AND STRUCTURE OF THE UPPER PART OF THE EXHUMED SAN GABRIEL FAULT, CALIFORNIA: IMPLICATIONS FOR FAULT PROCESSES AND SEISIMIC PROPERTIES
Published: 2022-10-22
Subjects: Physical Sciences and Mathematics
Quantifying shallow fault zone structure and characteristics is critical for accurately modeling the complex mechanical behavior of earthquakes as energy moves within faults from depth. We examine macro- to microstructures, mineralogy, and properties from drill core analyses of fault-related rocks in the steeply plunging ALT-B2 geotechnical borehole (total depth of 493 m) across the San Gabriel [...]
Advances in understanding subglacial meltwater drainage from past ice sheets
Published: 2022-10-22
Subjects: Physical Sciences and Mathematics
Meltwater drainage beneath ice sheets is a fundamental consideration for understanding ice-bed conditions and bed-modulated ice flow, with potential impacts on terminus behavior and ice-shelf mass balance. While contemporary observations reveal the presence of basal water movement in the subglacial environment and inferred styles of drainage, the geological record, including sediments and [...]
In Defense of Metrics: Metrics Sufficiently Encode Typical Human Preferences Regarding Hydrological Model Performance
Published: 2022-10-19
Subjects: Earth Sciences, Hydrology, Physical Sciences and Mathematics, Water Resource Management
Building accurate rainfall-runoff models is an integral part of hydrological science and practice. The variety of modeling goals and applications have led to a large suite of evaluation metrics for these models. Yet, hydrologists still put considerable trust into visual judgment, although it is unclear whether such judgment agrees or disagrees with existing quantitative metrics. In this study, we [...]
The impact of Holocene deglaciation and glacial dynamics on the landscapes and geomorphology of Potter Peninsula, King George Island (Isla 25 Mayo), NW Antarctic Peninsula
Published: 2022-10-19
Subjects: Earth Sciences, Geology, Geomorphology, Glaciology, Physical Sciences and Mathematics, Sedimentology
The timing and impact of deglaciation and Holocene readvances on the terrestrial continental margins of the Antarctic Peninsula have been well-studied but are still debated. Potter Peninsula on King George Island (Isla 25 de Mayo), South Shetland Islands (SSI), NW Antarctic Peninsula has a detailed assemblage of glacial landforms and stratigraphic exposures for constraining deglacial landscape [...]