Preprints
Filtering by Subject: Geology
Eocene (50-55 Ma) greenhouse climate recorded in nonmarine rocks of San Diego, CA, USA
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
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
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
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
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).
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
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
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
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
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
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 [...]
Geophysical and Geochemical Constraints on Magma Storage Depths along the Cascade Arc: Knowns and Unknowns
Published: 2023-05-03
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Volcanology
The iconic volcanoes of the Cascade arc stretch from Lassen Volcanic Center in northern California, through Oregon and Washington, to the Garibaldi Volcanic Belt in British Columbia. Recent studies have reviewed differences in the distribution and eruptive volumes of vents, as well as variations in geochemical compositions and heat flux along strike (amongst other characteristics). We investigate [...]
In-situ frictional behavior of subducting sediment in the shallow Nankai Trough
Published: 2023-04-22
Subjects: Geology, Geophysics and Seismology, Sedimentology, Tectonics and Structure
The transition from smectite to illite at around the depth with temperature of ~150 °C has long been hypothesized as one of controlling factors of the updip limit depth of the seismogenic zone of subduction zones. Although illite has a higher friction coefficient than smectite, previous friction experiments have little reported that the smectite-illite transition accompanies the transition from [...]
Assessing the potential of low transmissivity aquifers for ATES systems: a case study in Flanders (Belgium)
Published: 2023-04-21
Subjects: Geology, Sustainability, Water Resource Management
The Member States of the European Union pledged to reduce greenhouse gas emissions by 80-95% by 2050. Shallow geothermal systems might substantially contribute by providing heating and cooling in a sustainable way through seasonally storing heat and cold in the shallow ground (<200m). When the minimum yield to install a cost-effective aquifer thermal energy storage (ATES) system cannot be met, [...]
A key role for diffusion creep in eclogites: Omphacite deformation in the Zermatt-Saas Unit, Italian Alps
Published: 2023-04-18
Subjects: Earth Sciences, Geochemistry, Geology, Mineral Physics, Tectonics and Structure
Eclogites are important components of subduction-collision zones, with the mineral omphacite acting as the supporting framework mineral that accommodates the majority of any accumulated strain. As such it is important to determine which deformation mechanisms operate in omphacite during and after its formation to understand the rheology of deforming subducted crust. Such information is key to [...]