Preprints
Filtering by Subject: Geology
Subdivide and Conquer: Adapting Non-manifold Subdivision Surfaces to Surface-Based Representation and Reconstruction of Complex Geological Structures
Published: 2021-04-20
Subjects: Earth Sciences, Geology, Mining Engineering
Methods from the field of Computer Graphics are the foundation for the representation of geological structures in the form of geological models. However, as many of these methods have been developed for other types of applications, some of the requirements for the representation of geological features may not be considered and the capacities and limitations of different algorithms are not always [...]
A global hydrothermal reactor triggered prebiotic synthesis on Earth
Published: 2021-04-15
Subjects: Biogeochemistry, Earth Sciences, Geochemistry, Geology, Planetary Geology
Biosignatures in the rock record limit the time available for life to start on Earth to 600-800 million years1 (4.5-3.7 Ga; Hadean-Archean). Whether the conditions for the synthesis of complex organic molecules were unique to this time or remain present today is unclear, but understanding these conditions is essential for the search of life on other planets. The outer portion of the Hadean Earth [...]
Stress and Strain during Shock Metamorphism
Published: 2021-04-15
Subjects: Geology, Planetary Geology, Planetary Geophysics and Seismology, Tectonics and Structure
Shock metamorphism is the process by which rocks, and the minerals within them, transform during the passage of a shock wave. Shock effects, such as shatter cones, are critical for the identification of impact structures and have commonly been used to infer mechanical and structural information on the cratering process. To make these inferences, the mechanics of shock wave behavior must be [...]
Paleoclimate Changes in the Pacific Northwest Over the Past 36,000 Years from Clumped Isotope Measurements and Isotope-Enabled Model Analysis
Published: 2021-04-07
Subjects: Climate, Geochemistry, Geology, Physical Sciences and Mathematics, Soil Science
Since the last glacial period, North America has experienced dramatic changes in regional climate, including the collapse of ice sheets and changes in effective precipitation. We use clumped isotopes and analysis of transient climate simulations to provide constraints on hydroclimate changes in the Pacific Northwest. The coldest soil temperatures (~10.5 ±1.°C to 14.9 ±1.2°C) occurred [...]
Orbital, the Box - An interactive educational tool for in-depth understanding of astronomical climate forcing.
Published: 2021-04-07
Subjects: Adult and Continuing Education, Astrophysics and Astronomy, Climate, Earth Sciences, Education, Educational Methods, Geology, Geophysics and Seismology, Higher Education, Instructional Media Design, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, The Sun and the Solar System
“Orbital, the Box” provides an interactive tool with graphical user interface (GUI) for stimulating active, visual learning for understanding of astronomical climate forcing. This cross-platform tool can be run locally on a personal computer using a standard web browser environment with no need for plugins, thus maximising accessibility for students and teachers alike. The tool facilitates in the [...]
The concavity of submarine canyon longitudinal profiles
Published: 2021-04-07
Subjects: Earth Sciences, Geology, Geomorphology, Physical Sciences and Mathematics, Sedimentology
Submarine canyons incise continental shelves and slopes, and are important conduits for the transport of sediment, nutrients, organic carbon and pollutants from continents to oceans. Submarine canyons bear morphological similarities to subaerial valleys, such as their longitudinal (long) profiles. Long profiles record the interaction between erosion and uplift, making their shape, or concavity, a [...]
Precious and Critical Metal-Bearing Assemblages in the Ann Mason Copper Porphyry Deposit, Yerington, Nevada
Published: 2021-04-07
Subjects: Geology
Porphyry deposits are an important source of copper and their value may be upgraded by minor contents of precious metals, if they are extractable. The mechanisms for enrichment of precious and base metals in these systems are not well understood. This study investigates the deportment of trace metals in the Ann Mason porphyry deposit, including gold, silver, palladium, mercury, lead and bismuth. [...]
Crustal-scale listric geometry of the San Andreas Fault driven by lower crustal flow
Published: 2021-03-31
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Physical Sciences and Mathematics
The San Andreas Fault (SAF) is one of the dominant components of the transform boundary between the Pacific and the North American Plate. Although the fault is verti-cal-to sub-vertical at shallow (<10 km) depth, it variably dips at angles of ca. 40-70º to the southwest near the western Transverse Range and to the northeast in its southern seg-ment at depths of ca. 10-20 km, and thus can be [...]
The joint sets on the Lilstock Benches, UK. Observations based on mapping a full resolution UAV-based image
Published: 2021-03-29
Subjects: Geology
Outcrop studies of fracture networks are important to understand fractured reservoirs in the subsurface, but complete maps of all fractures in large outcrops are rare due to limitations of outcrop and image resolution. We manually mapped the first full-resolution UAV-based, Gigapixel dataset and DEM of the wave-cut Lilstock Benches in the southern Bristol Channel basin, a classic outcrop of [...]
Mechanical Stratigraphy Controls Normal Fault Growth and Dimensions, Outer Kwanza Basin, Offshore Angola
Published: 2021-03-19
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
Mechanical stratigraphy controls the growth patterns and dimensions of relatively small normal faults, yet how its influences the development of much larger structures remains unclear. Here we use 3D seismic reflection data from the Outer Kwanza Basin, offshore Angola to constrain the geometry and kinematics of several normal faults formed in a deep-water clastic succession. The faults are up to [...]
Correlative Microscopy: a tool for understanding soil weathering in modern analogues of early terrestrial biospheres
Published: 2021-03-18
Subjects: Biogeochemistry, Geology, Paleobiology, Plant Sciences, Research Methods in Life Sciences, Sedimentology, Soil Science
Correlative imaging provides a method of investigating complex systems by combining analytical (chemistry) and imaging (tomography) information across dimensions (2D-3D) and scales (centimetres-nanometres). We studied weathering processes in a modern cryptogamic ground cover (CGC) from Iceland, containing early colonizing, and evolutionary ancient, communities of mosses, lichens, fungi, and [...]
Polygenetic mélange in the retrowedge foredeep of an active arc-continent collision, Coastal Range of eastern Taiwan (accepted manuscript)
Published: 2021-03-17
Subjects: Earth Sciences, Geology, Sedimentology, Stratigraphy, Tectonics and Structure
The Plio-Pleistocene Lichi Mélange in the Coastal Range of eastern Taiwan offers an excellent opportunity to study processes of mélange development at the continent-ocean interface of an active arc-continent collision. This paper presents new results of detailed geologic mapping, lithofacies analysis, magneto-biostratigraphy, paleocurrent, and paleoslope analyses in the southern Coastal Range to [...]
Long-term evolution of Earth's continental surface elevation
Published: 2021-03-17
Subjects: Geology, Geomorphology
Determining the timescale over which continental surface elevation (hypsometry) evolves is difficult because it reflects a combination of isostasy and dynamic topography operating in concert with erosion and deposition. Here, we use 252 million year old and younger shallow marine sediments exposed at the surface as tracers of net change in continental surface elevation over time. In aggregate, we [...]
Silurian carbonate high-energy deposits of potential tsunami origin: distinguishing lateral redeposition and time averaging using carbon isotope chemostratigraphy
Published: 2021-03-17
Subjects: Earth Sciences, Geochemistry, Geology, Sedimentology, Stratigraphy
Stable carbon isotope curves are used as a precise stratigraphic tool in the Paleozoic, even though they are commonly based on shallow-water carbonate record, characterized by low stratigraphic completeness. Identification of episodes of large-scale redeposition and erosion may improve δ13Ccarb-based correlations. Here, a series of at least three episodes of high-energy onshore redeposition are [...]
The Sidi Ifni transect across the rifted margin of Morocco (Central Atlantic): Vertical movements constrained by low-temperature thermochronology
Published: 2021-03-17
Subjects: Earth Sciences, Geology, Geomorphology, Paleontology, Sedimentology, Stratigraphy, Tectonics and Structure
The occurrence of km-scale exhumations during syn- and post-rift stages has been documented along Atlantic continental margins, which are also characterised by basins undergoing substantial subsidence. The relationship between the exhuming and subsiding domains is poorly understood. In this study, we reconstruct the evolution of a 50 km long transect across the Moroccan rifted margin from the [...]