Preprints

Filtering by Subject: Geology

Generation of LOMU type alkali basalts in East Asia by melting and melt metasomatism of the asthenospheric mantle by a Paleoproterozoic subducted slab component

Bidisha Dey, Tomoyuki Shibata, Masako Yoshikawa

Published: 2023-08-30
Subjects: Geochemistry, Geology, Volcanology

The origin of alkali basalts with distinctive time-integrated low U/Pb (low µ, LOMU) from East Asia is controversial due to the complex geochemical and tectonic signatures reported from this region. We report new data on the petrology and geochemistry of the Higashi-Matsuura and Kita-Matsuura alkali basalts from southwest Japan, which confirm the presence of a LOMU-type mantle component below the [...]

Garnet zoning patterns record multiple processes of chemical transfer during subduction

Freya Roxanne George, Daniel R Viete, Janaína N. Ávila, et al.

Published: 2023-08-24
Subjects: Geology, Other Earth Sciences

Subduction facilitates the transfer of volatiles from the Earth’s surface to its interior. However, the rock-scale processes that govern the efficiency of deep volatile transfer are not fully understood. Garnets from subduction zone rocks commonly have fine-scale, oscillatory elemental zoning that is typically considered to record external fluid ingress/transfer. Elemental and oxygen-isotope [...]

Spontaneous Unsteadiness and Sorting in Pyroclastic Density Currents and their Deposits

Pete Rowley, Rebecca Williams, Matthew Johnson, et al.

Published: 2023-08-22
Subjects: Geology, Sedimentology, Stratigraphy, Volcanology

Pyroclastic density currents (PDCs) pose substantial risk to populations living on and around active volcanoes, but their structure and internal dynamics are poorly understood. Much of this understanding is derived from interpretation of their widespread deposits. Scaled experiments are able to probe different conditions, to explore how changing flow dynamics relate to the wide variety of [...]

Generation of evolving plate boundaries and toroidal flow from visco-plastic damage-rheology mantle convection and continents

Thorsten W. Becker, Lukas Fuchs

Published: 2023-08-17
Subjects: Geology, Geophysics and Seismology, Tectonics and Structure

Earth's style of planetary heat transport is characterized by plate tectonics which requires rock strength to be reduced plastically in order to break an otherwise stagnant lithospheric lid, and for rocks to have a memory of past deformation to account for strain localization and the hysteresis implied by geological sutures. Here, we explore $\sim$10$^7$ Rayleigh number, visco-plastic, [...]

Eocene (50-55 Ma) greenhouse climate recorded in nonmarine rocks of San Diego, CA, USA

Adrian Broz, Devin Pritchard-Peterson, Sarah Schneider, et al.

Published: 2023-08-08
Subjects: Chemistry, Climate, Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics, Soil Science, Stratigraphy

Nonmarine rocks in sea cliffs of southern California store a detailed record of weathering under tropical conditions millions of years ago, where today the climate is much drier and cooler. This work examines early Eocene (~50-55 million-year-old) deeply weathered paleosols (ancient, buried soils) exposed in marine terraces of northern San Diego County, California, and uses their geochemistry and [...]

Tephra dispersal and composition reveal the explosive onset of a large basaltic fissure eruption: Timanfaya, Lanzarote, 1730–1736 CE

James K. Muller, Marc-Antoine Longpré

Published: 2023-08-03
Subjects: Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics, Stratigraphy, Volcanology

Basaltic fissure eruptions are chiefly characterized by sizable emissions of lava flows and volcanic gases, posing significant hazards. However, such eruptions may be punctuated by explosive episodes, which are comparatively poorly understood but may have important volcanic hazard and environmental implications. The 1730–1736 CE Timanfaya eruption on Lanzarote, Canary Islands, is a large basaltic [...]

Soil geochemistry of hydrogen and other gases along the San Andreas Fault

Yashee Mathur, Victor Awosiji, Tapan Mukerji, et al.

Published: 2023-07-23
Subjects: Environmental Chemistry, Geochemistry, Geology, Multivariate Analysis, Oil, Gas, and Energy, Soil Science

Natural hydrogen has generated great interest as a potential clean and renewable energy source. To understand the occurrence of natural hydrogen, 103 1-m deep soil gas samples were acquired near the San Andreas Fault at Jasper Ridge and Portola Valley, California, USA. The gas samples were analyzed for hydrogen, helium, carbon dioxide, light hydrocarbons, and fixed gas concentrations. Statistical [...]

Physically based Probabilistic Rainfall Intensity-Duration (ID) Thresholds for Runoff-Generated Debris Flows

Oliver Francis, Hui Tang, Martino Bernard

Published: 2023-07-21
Subjects: Earth Sciences, Geology, Geomorphology, Hydrology

Runoff-generated debris flows are common hazards in mountainous regions, causing millions of dollars lost and hundreds of casualties yearly. Early warning systems based on rainfall thresholds have been implemented to reduce the impact of these hazards. These thresholds tend to be based on short monitoring periods, which cannot fully capture the varying responses of catchments to rainfall. As a [...]

Discovery of a new 12-km impact crater candidate at As Sail Al Kabeer, Saudi Arabia

Abdulrahman Toonsi

Published: 2023-07-11
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Planetary Geology, Planetary Sciences

The Arabian shield of Saudi Arabia likely has many impact craters due to the old age of its rocks, however many of them have not yet been discovered due to their resemblance to plutons. Using satellite imagery, a 12-km wide circular structure with a central peak was identified at As Sail Al Kabeer, 40 kilometers north of the city of Taif in western Saudi Arabia. Fieldwork has shown that this [...]

Sedimentology and sequence stratigraphy of shallow-marine, coarse-grained siliciclastic deposits in the southern Utsira High: the Late Jurassic intra-Draupne Formation sandstones in the Johan Sverdrup Field (Norwegian North Sea).

Josep Maria Puig Lopez, Miquel Poyatos-Moré, John Howell

Published: 2023-06-30
Subjects: Earth Sciences, Geology, Sedimentology, Stratigraphy, Tectonics and Structure

Thin, condensed coarse-grained shallow-marine successions can be difficult to describe and interpret, especially in the subsurface because they commonly lack finer grained intervals which are typically associated with sequence stratigraphic surfaces. This lack of mudstones and siltstones means that they also typically make excellent reservoir intervals. The Oxfordian to Volgian intra-Draupne [...]

Mind the uncertainty: Global plate model choice impacts deep-time palaeobiological studies

Lucas Buffan, Lewis Alan Jones, Mathew Domeier, et al.

Published: 2023-06-23
Subjects: Biodiversity, Climate, Earth Sciences, Ecology and Evolutionary Biology, Geology, Life Sciences, Paleobiology, Paleontology, Physical Sciences and Mathematics, Tectonics and Structure

1. Global plate models (GPMs) aim to reconstruct the tectonic evolution of the Earth by modelling the motion of the plates and continents through time. These models enable palaeobiologists to study the past distribution of extinct organisms. However, different GPMs exist that vary in their partitioning of the Earth's surface and the modelling of continental motions. Consequently, the preferred [...]

Innovating and networking global geochemical data resources through OneGeochemistry

Alexander Martijn Prent, Dominik C Hezel, Marthe Klöcking, et al.

Published: 2023-06-14
Subjects: Biogeochemistry, Cosmochemistry, Databases and Information Systems, Geochemistry, Geology, Planetary Biogeochemistry, Planetary Geochemistry, Planetary Geology, Volcanology

A vision of the not-to-distant future: Imagine yourself as a researcher who is making plans for fieldwork in the Andes Mountains. You are behind your computer and load a three-dimensional visualisation of the Earth and its geology to investigate the research already done in the southern Patagonian regions. You zoom in to the mountain range of interest and select various data layers to show [...]

Discovery of a 15-kilometer-wide impact crater candidate in western Saudi Arabia

Abdulrahman Toonsi

Published: 2023-05-31
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Planetary Geology

There are few reports on impact craters in Saudi Arabia. This paper aims to fill a gap in the literature in this area. Using satellite imaging, a circular structure with a diameter of approximately 15 kilometers was detected on the edge of Harrat Rahat volcanic field in western Saudi Arabia. Fieldwork showed that the circular structure is a newly-discovered comet impact crater candidate, this [...]

Comment on ‘The magmatic architecture and evolution of the Chang’e-5 lunar basalts’ Penny E. Wieser1, Christy Till2, Adam Kent3, Matthew Gleeson1

Penny E Wieser, Christy Till, Adam Kent, et al.

Published: 2023-05-31
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Volcanology

Luo et al.1 present exciting new data on lunar basalt samples erupted at ~2 Ga, and brought to Earth by the Chang’e-5 (CE-5) mission. These samples offer important new opportunities to understand lunar magmatic systems. Luo et al.1 use Clinopyroxene-Liquid (Cpx-Liq) thermobarometry and pMELTS modelling of mineral compositions to determine the pressures (P) and temperatures (T) of magma storage on [...]

Formulating and Solving the Data-Consistent Geophysical Inverse Problem for Subsurface Modeling Applications

Alex Miltenberger, Lijing Wang, Tapan Mukerji, et al.

Published: 2023-05-27
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Probability

Today, most probabilistic geophysical inverse problems are formulated using one of two methods: (1) conditional probability and Bayes’ Theorem, or (2) Tarantola’s theory of intersecting probability densities. More recently, a third inverse problem formulation based on pushforward probability measures was proposed, termed “data-consistent inversion”. Many practical problems can be cast into any of [...]

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