Preprints
Filtering by Subject: Geology
Short Communication: The Wasserstein distance as a dissimilarity metric for comparing detrital age spectra, and other geological distributions
Published: 2022-10-26
Subjects: Earth Sciences, Environmental Sciences, Geochemistry, Geology, Geomorphology, Stratigraphy, Tectonics and Structure
Distributional data such as detrital age populations or grain size distributions are common in the geological sciences. As analytical techniques become more sophisticated, increasingly large amounts of distributional data are being gathered. These advances require quantitative and objective methods, such as multidimensional scaling (MDS), to analyse large numbers of samples. Crucial to such [...]
palaeoverse: a community-driven R package to support palaeobiological analysis
Published: 2022-10-26
Subjects: Geology, Paleobiology, Paleontology
1. The open-source programming language ‘R’ has become a standard tool in the palaeobiologist’s toolkit. Its popularity within the palaeobiology community continues to grow, with published articles increasingly citing the usage of R and R packages. However, there are currently a lack of agreed standards for data preparation and available frameworks to support implementation of such standards. [...]
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 [...]
GANSim-surrogate: An integrated framework for conditional geomodelling and uncertainty analysis
Published: 2022-10-24
Subjects: Computational Engineering, Earth Sciences, Environmental Engineering, Fluid Dynamics, Geology, Geophysics and Seismology, Hydrology, Sedimentology
We propose a deep-learning framework (GANSim-surrogate) for conditioning subsurface geomodel realizations to static data and dynamic flow data. The static data includes well facies data, interpreted facies probability maps, and non-spatial global features, while dynamic data can include well data such as pressures and flow rates. The framework consists of a Convolutional Neural Network (CNN) [...]
Multiple ocean oxygenation events during the Ediacaran Period: Mo isotope evidence from the Nanhua Basin, South China
Published: 2022-10-24
Subjects: Earth Sciences, Geochemistry, Geology
The Ediacaran Period (ca. 635–539 Ma) was an eventful interval in Earth history, during which a succession of biological and environmental changes, including episodic ocean oxygenation events (OOEs), may have paved the way for the Cambrian radiations of animal life. To better understand the evolution of ocean redox conditions and to estimate the extent of seafloor oxygenation during this period, [...]
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 [...]
Fault Friction Derived from Fault Bend Influence on Coseismic Slip During the 2019 Ridgecrest Mw 7.1 Mainshock
Published: 2022-10-18
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure
The variation of stress on faults is important for our understanding of fault friction and the dynamics of earthquake ruptures. However, we still have little observational constraints on their absolute magnitude, or their variations in space and in time over the seismic cycle. Here we use a new geodetic imaging technique to measure the 3D coseismic slip vectors along the 2019 Ridgecrest surface [...]
Characterising the internal structural complexity of the Southern North Sea Zechstein Supergroup Evaporites
Published: 2022-10-08
Subjects: Earth Sciences, Geology, Tectonics and Structure
The internal complexity present within layered evaporite sequences is often an overlooked feature in sedimentary basins, with attention frequently concentrating on the external geometries that salt bodies form. Through the availability of large areas of 3D seismic data and new seismic imaging techniques the opportunity to view the internal structures that form within layered evaporites allows for [...]
Comparative study of alteration sequences in pegmatitic aluminium phosphates
Published: 2022-09-29
Subjects: Earth Sciences, Geochemistry, Geology, Mineral Physics, Other Earth Sciences
Aluminium phosphates are mineral phases commonly occurring in rare-element pegmatites that record initial magmatic crystallization, metasomatic and hydrothermal replacements and precipitation and low-temperature alteration. Here we perform a comparative mineralogical study between several localities to assess similarities and variations in these parageneses and establish a general alteration [...]
Characterisation of phosphate mineralogy in Montebras-en-Soumans Pegmatite, Massif Central, France
Published: 2022-09-22
Subjects: Earth Sciences, Geochemistry, Geology, Mineral Physics
Montebras-en-Soumans pegmatitic cupola hosts large pods of phosphate composed of primary amblygonite-montebrasite. These aluminium phosphate masses are considerably altered by post-magmatic processes producing a number of secondary metasomatic hydrothermal phosphates (lacroixite, wardite, morinite, viitaniemiite, apatite, triplite, eosphorite) and low-temperature phosphates (apatite, crandallite, [...]
python-ags4: A Python library to read, write, and validate AGS4 geodata files
Published: 2022-09-21
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Environmental Engineering, Geochemistry, Geology, Geophysics and Seismology, Geotechnical Engineering
Data gathered from geotechnical, geoenvironmental, and geophysical investigations can be broadly described as "geodata". The AGS4 data format is one of the most widely used data transmittal formats for geodata and is used across the world. It is a plain text format consisting of multiple tables of comma-separated values, tied together with a robust data schema and a comprehensive suite of [...]
North Atlantic Drift Sediments Constrain Eocene Tidal Dissipation and the Evolution of the Earth-Moon System
Published: 2022-09-15
Subjects: Geochemistry, Geology, Sedimentology, Stratigraphy
Cyclostratigraphy and astrochronology are now at the forefront of geologic timekeeping. While this technique heavily relies on the accuracy of astronomical calculations, solar system chaos limits how far back astronomical calculations can be performed with confidence. High-resolution paleoclimate records with Milankovitch imprints now allow reversing the traditional cyclostratigraphic approach: [...]
Rapid fault healing after seismic slip
Published: 2022-09-01
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Tectonics and Structure
Fault strength recovery (healing) following an earthquake is a key process in controlling the recurrence of future events; however, the rates and mechanisms of fault healing are poorly constrained. Here, by performing high-velocity friction experiments at seismic slip rates (0.57 m/s), we show that granite and gabbro fault gouges recover their strength rapidly after experiencing dynamic [...]
Down-delta hydraulic geometry and its application to the rock record
Published: 2022-08-31
Subjects: Earth Sciences, Geology, Geomorphology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy
Paleodischarge estimation is largely undertaken within fluvial settings, and there are limited paleodischarge estimates specifically from delta deposits, despite their significance globally. Making water paleodischarge estimates for deltas using catchment-based approaches developed using data from fluvial settings requires estimation of parameters from the rock record (e.g. paleotemperature, [...]
Practical sampling criteria for using delta channel width to estimate paleodischarge in the rock record
Published: 2022-08-31
Subjects: Earth Sciences, Geology, Geomorphology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy
Quantifying paleodischarge from geological field observations have been for decades, and remains, a key research challenge. Several paleodischarge scaling relationships have been developed for fluvial environments, such as BQART, Fulcrum and regional hydraulic geometry or for river deltas by precluding the role of wave and tide. In deltas where marine (wave, tide) energy causes bidirectional [...]