Preprints

Filtering by Subject: Physical Sciences and Mathematics

Post-salt magmatism in the Campos Basin, offshore SE Brazil: style, distribution, and relationship to salt tectonics

Francyne Bochi do Amarante, Christopher Aiden-Lee Jackson, Leonardo Muniz Pichel

Published: 2022-09-28
Subjects: Physical Sciences and Mathematics

Substantial magmatism occurred during the development of the marginal basins of the central and southern South Atlantic. Situated on the Brazilian side of the central segment, the Campos and Santos basin represent a transitional margin, located between the magma-rich margin in the north and the magma-poor margin in the south. In addition to magmatism associated with the initiation of continental [...]

Cautionary tales from the mesoscale eddy diffusivity tensor

Takaya Uchida, Dhruv Balwada, Quentin Jamet, et al.

Published: 2022-09-26
Subjects: Physical Sciences and Mathematics

The anisotropic mesoscale eddy diffusivity tensor is diagnosed using passive tracers advected in both an idealized 101-member mesoscale-resolving quasi-geostrophic (QG) double-gyre ensemble, and a realistic 24-member eddying ($1/12^\circ$) ensemble of the North Atlantic. We assert that the Reynold's decomposition along the ensemble dimension, rather than the spatial or temporal dimension, allows [...]

All aboard! Earth system investigations with the CH2O-CHOO TRAIN v1.0

Tyler Kukla, Daniel Enrique Ibarra, Kimberly V. Lau, et al.

Published: 2022-09-24
Subjects: Climate, Earth Sciences, Geochemistry, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics

Models of the carbon cycle and climate on geologic (>10^4 year) timescales have improved tremendously in the last 50 years due to parallel advances in our understanding of the Earth system and the increase in computing power to simulate its key processes. Despite these advances, balancing the Earth System's vast complexity with a model's computational expense is a primary challenge in model [...]

CloudSEN12 - a global dataset for semantic understanding of cloud and cloud shadow in Sentinel-2

Cesar Aybar, Luis Ysuhuaylas, Jhomira Loja, et al.

Published: 2022-09-24
Subjects: Computer Sciences, Earth Sciences, Physical Sciences and Mathematics

Accurately characterizing clouds and their shadows is a long-standing problem in the Earth Observation community. Recent works showcase the necessity to improve cloud detection methods for imagery acquired by the Sentinel-2 satellites. However, the lack of consensus and transparency in existing reference datasets hampers the benchmarking of current cloud detection methods. Exploiting the [...]

Intra-channel detachment in a collisional orogen: the Jhala Normal Fault in the Bhagirathi river section, Garhwal Higher Himalaya, India

Narayan Bose, Takeshi Imayama, Ryoichi Kawabata, et al.

Published: 2022-09-24
Subjects: Physical Sciences and Mathematics

In the Bhagirathi River Transect of the Garhwal Himalaya, India, the existence of the Jhala Normal Fault (JNF) and its movement sense are disputed. The JNF has been considered either as part of the South Tibetan Detachment System (STDS) or as a distinct, more southerly discontinuity within the Higher Himalayan Crystalline Sequence (HHCS). Field studies reveal that the JNF lies entirely within the [...]

Complex evolution of the 2016 Kaikoura earthquake revealed by teleseismic body waves

Kenta Ohara, Yagi Yuji, Shinji Yamashita, et al.

Published: 2022-09-23
Subjects: Physical Sciences and Mathematics

The 2016 Kaikoura earthquake, New Zealand, ruptured more than a dozen faults, making it difficult to prescribe a model fault for analysing the event by inversion. To model this earthquake from teleseismic records, we used a potency density tensor inversion, which projects multiple fault slips onto a single model fault plane, which reduced the non-uniqueness due to the uncertainty in selecting the [...]

Marine Radiocarbon Calibration in Polar Regions: A Simple Approximate Approach using Marine20

Timothy J Heaton, Martin Butzin, Edouard Bard, et al.

Published: 2022-09-22
Subjects: Earth Sciences, Environmental Sciences, Mathematics, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Statistics and Probability

The Marine20 radiocarbon (14C) age calibration curve, and all earlier marine radiocarbon calibration curves from the IntCal group, must be used extremely cautiously for the calibration of marine 14C samples from polar regions (outside ~ 40ºS – 40ºN) during glacial periods. Calibrating polar 14C marine samples from glacial periods against any Marine calibration curve (Marine20 or any earlier [...]

Ocean heat uptake efficiency increase since 1970

B. B. Cael

Published: 2022-09-21
Subjects: Earth Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics

The ocean stores the bulk of anthropogenic heat in the Earth system. The ocean heat uptake efficiency (OHUE) -- the flux of heat into the ocean per degree of global warming -- is therefore a key factor in how much warming will occur in the coming decades. In climate models, OHUE is well-characterised, tending to decrease on centennial timescales; in contrast, OHUE is not well-constrained from [...]

Volcanic Lightning and Prebiotic Chemistry on the Early Earth

Jeffrey L Bada

Published: 2022-09-16
Subjects: Chemistry, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics

Based on the paper by Pan et al., on the early Earth >4.2 Ga with limited exposed land areas, coupled with an ice covered ocean, lightning could have been rare. This presents a conundrum because lightning is considered to be an important energy source needed for the synthesis of prebiotic compounds required for the origin of life. Lightning occurrence during eruptions on wide spread volcanic [...]

Secular change of true polar wander over the past billion years

Hairuo Fu, Shihong Zhang, Daniel Condon, et al.

Published: 2022-09-15
Subjects: Physical Sciences and Mathematics

The rate of movement of Earth’s solid shell relative to its spin axis, or true polar wander, depends on variations in mantle convection and viscosity. We report paleomagnetic and geochronologic data from South China that constrain the rate of rapid true polar wander (>5° Myr-1) from 832–821 million years ago. Analysis of the paleomagnetic database demonstrates secular change of true polar wander [...]

The Equator Project

Natasha Joanne Dowey, Sam Giles, Christopher Aiden-Lee Jackson, et al.

Published: 2022-09-10
Subjects: Education, Physical Sciences and Mathematics

Geography, Earth and Environmental Science (GEES) research will play a vital role in addressing the grand challenges of the 21st century, contributing to many of the UN sustainable development goals and the global energy transition. However, geoscience knowledge cannot be successfully applied to global problems that impact people from all walks of life unless the discipline itself is equitable. [...]

Lithogeochemistry in exploration for intrusion-hosted magmatic Ni-Cu-Co deposits

Steve Barnes

Published: 2022-09-09
Subjects: Physical Sciences and Mathematics

Magmatic Ni-Cu-Co-PGE deposits are notoriously difficult exploration targets owing to a lack of alteration haloes or other extended distal footprints. Success requires prediction of prospective terranes, followed by identification of suitable host intrusions and deposition sites within those intrusions. At the regional scale, potential ore-hosting magmas tend to have lithophile trace element [...]

Wavelet-based wavenumber spectral estimate of eddy kinetic energy: Theory

Takaya Uchida, Quentin Jamet, Andrew C. Poje, et al.

Published: 2022-09-09
Subjects: Physical Sciences and Mathematics

A wavelet-based method is introduced in an oceanographic context to estimate wavenumber spectrum and spectral flux of kinetic energy and enstrophy. We apply this to a numerical simulation of idealized, doubly-periodic quasi-geostrophic flows, i.e.~the flow is constrained by the Coriolis force and vertical stratification. The double periodicity allows for a straightforward Fourier analysis as [...]

Seasonal flow types of glaciers in Sermilik Fjord, Greenland, over 2016–2021

Kristin Poinar

Published: 2022-09-08
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics

Greenland glaciers have three primary seasonal ice flow patterns, or “types”: terminus driven, runoff driven, and runoff adapting. To date, glacier types have been identified by analyzing flow at a single location near the terminus; information at all other locations is discarded. Here, we use principal component (PC) / empirical orthogonal function (EOF) analysis to decompose multi-year time [...]

The impacts of mineral dust aerosols on global climate and climate change

Jasper F Kok, Trude Storelvmo, Vlassis Karydis, et al.

Published: 2022-09-08
Subjects: Physical Sciences and Mathematics

Mineral dust aerosols impact Earth’s energy budget through interactions with radiation, clouds, atmospheric chemistry, the cryosphere and biogeochemistry. In this review, we summarize these interactions and assess the resulting impacts of dust, and of changes in dust, on global climate and climate change. We find that the total effect of these interactions on Earth’s global energy budget—the dust [...]

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