Preprints
Filtering by Subject: Earth Sciences
Benthic biofilm potential for organic carbon accumulation in salt marsh sediments
Published: 2021-04-02
Subjects: Biogeochemistry, Earth Sciences, Geomorphology
Coastal salt marshes are productive environments with high potential for carbon accumulation and storage. Even though organic carbon in salt marsh sediment is typically attributed to plant biomass, it can also be produced by benthic photosynthetic biofilms. These biofilms, generally composed of diatoms and their secretions, are known for their high primary productivity and contribution to the [...]
An overview of the evolving jurisdictional scope of the U.S. Clean Water Act for hydrologists
Published: 2021-04-02
Subjects: Earth Sciences, Environmental Sciences, Hydrology, Physical Sciences and Mathematics, Water Resource Management
The Clean Water Act (CWA) is the primary federal mechanism by which the physical, chemical, and biological integrity of streams, lakes, and wetlands are protected in the U.S. The CWA has evolved considerably since its initial passage in 1948, including explicit expansions and contractions of jurisdictional scope through a series of legislative actions, court decisions, and agency rules. Here, we [...]
Globally resolved surface temperatures since the Last Glacial Maximum
Published: 2021-03-31
Subjects: Climate, Earth Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Climate changes across the last 24,000 years provide key insights into Earth system responses to external forcing. Climate model simulations and proxy data have independently allowed for study of this crucial interval; however, they have at times yielded disparate conclusions. Here, we leverage both types of information using paleoclimate data assimilation to produce the first observationally [...]
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 [...]
Towards a morphology diagram for terrestrial carbonates: evaluating the impact of carbonate supersaturation and alginic acid in calcite precipitate morphology
Published: 2021-03-30
Subjects: Earth Sciences, Environmental Sciences, Physical Sciences and Mathematics
Ancient and recent terrestrial carbonate-precipitating systems are characterised by a heterogeneous array of deposits volumetrically dominated by calcite. In these environments, calcite precipitates display an extraordinary morphological diversity, from single crystal rhombohedral prisms, to blocky crystalline encrustations, or spherulitic to dendritic aggregates. Despite many decades of thorough [...]
A data assimilation framework to constrain the driving processes of anthropogenically induced subsidence
Published: 2021-03-25
Subjects: Earth Sciences, Environmental Sciences, Oil, Gas, and Energy, Statistics and Probability
Surface movement can be induced by many human subsurface activities: natural gas production, geothermal heat extraction, ground water extraction, phreatic groundwater level lowering, storage of natural gas and CO2. In this manuscript, we focus on subsidence caused by gas production. While geological interpretations, seismic campaigns and flow modeling often provide a relatively rich pre-existing [...]
Resolving Northern Alaska Earthquake Sequences Using the Transportable Array and Probabilistic Location Methods
Published: 2021-03-25
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure
Between 2014 and 2017, almost 200 new seismic stations were installed in Alaska and northwestern Canada as part of the EarthScope USArray Transportable Array. These stations currently provide an unprecedented capability for the detection and location of seismic events in regions with otherwise relatively sparse station coverage. Two interesting earthquake sequences in 2018 and 2019 in the [...]
Slab temperature evolution over the lifetime of a subduction zone
Published: 2021-03-24
Subjects: Earth Sciences, Geophysics and Seismology
The thermal evolution of subducting slabs controls a range of subduction processes, yet we lack a robust understanding of how thermal structure develops over a subduction zone’s lifetime. We investigate the time-dependence of slab thermal structure using dynamically consistent, time evolving models. Pressure-temperature (P-T) conditions along the slab Moho and slab top exhibit substantial [...]
Microanchored fiber-optic DSS in boreholes allows strain profiling of the shallow subsurface
Published: 2021-03-22
Subjects: Earth Sciences, Engineering
Vertical deformation profiles of subterranean geological formations are conventionally measured by borehole extensometry. Distributed strain sensing (DSS) paired with fiber-optic cables installed in the ground opens up possibilities for acquiring high-resolution static and quasistatic strain profiles of deforming strata, but it is currently limited by reduced data quality due to complicated [...]
Western Gondwana imaged by S receiver-functions (SRF): new results on Moho, MLD (mid-lithospheric discontinuity) and LAB (lithosphere-asthenosphere boundary)
Published: 2021-03-21
Subjects: Earth Sciences, Physical Sciences and Mathematics
We study the Moho, the mid-lithospheric discontinuity (MLD), and the lithosphere-asthenosphere boundary (LAB) from southern Africa to northern Arabia, from Archean cratons to active rifts, at 1° resolution using our comprehensive new database of shear-wave receiver functions (SRFs). The good agreement between the Moho depth obtained from our SRFs and published P-wave receiver function (PRF) [...]
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 [...]
A Global Set of Subduction Zone Earthquake Scenarios and Recurrence Intervals Inferred From Geodetically Constrained Block Models of Interseismic Coupling Distributions
Published: 2021-03-18
Subjects: Earth Sciences
The past 100 years have seen the occurrence of five $\MW\geq9$ earthquakes and 94 $\MW\geq8$ earthquakes. Here we assess the potential for future great earthquakes using inferences of interseismic subduction zone coupling from a global block model incorporating both tectonic plate motions and earthquake cycle effects. Interseismic earthquake cycle effects are represented using a first-order [...]
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 [...]
Formation of continental microplates through rift linkage: Numerical modelling and its application to the Flemish Cap and Sao Paulo Plateau
Published: 2021-03-17
Subjects: Earth Sciences, Physical Sciences and Mathematics
Continental microplates are enigmatic plate boundary features, which can occur in extensional and compressional regimes. Here we focus on microplate formation and their temporal evolution in continental rift settings. To this aim, we employ the geodynamic finite element software ASPECT to conduct 3D lithospheric-scale numerical models from rift inception to continental breakup. We find that [...]
Controls on the spatio-temporal patterns of induced seismicity in Groningen constrained by physics-based modeling with Ensemble-Smoother data assimilation
Published: 2021-03-17
Subjects: Earth Sciences, Oil, Gas, and Energy
The induced seismicity in the Groningen gas field, The Netherlands, presents contrasted spatio-temporal patterns between the central area and the south west area. Understanding the origin of this contrast requires a thorough assessment of two factors: (1) the stress development on the Groningen faults, and (2) the frictional response of the faults to induced stresses. Both factors have large [...]