Preprints
Filtering by Subject: Geology
Architecture and controls of thick, intensely bioturbated, storm-influenced shallow-marine successions: an example from the Jurassic Neuquén Basin (Argentina)
Published: 2020-06-05
Subjects: Earth Sciences, Geology, Paleontology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy, Tectonics and Structure
Thick (>100 m-thick), highly bioturbated storm-influenced shallow-marine deposits are not frequent in the stratigraphic record, but they tend to be unusually common in aggradational to retrogradational successions. Individual storm-event beds have typically low preservation in these successions, yet depositional settings are characterized on the basis of storms processes. We present a [...]
Brittle Deformation of Carbonated Peridotite – Insights from Listvenites of the Samail Ophiolite (Oman Drilling Project Hole BT1B)
Published: 2020-05-27
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics
Hole BT1B of the Oman Drilling Project provides a continuous sampling from listvenite into the metamorphic sole that preserves the deformation, hydration and carbonation processes of oceanic mantle peridotite at the base of the Samail ophiolite, Oman. We present evidence of multistage brittle deformation in listvenites and serpentinites based on field observations, visual core logging and [...]
Preservation of Organic Carbon in Dolomitized Cambrian Stromatolites and Implications for Microbial Biosignatures in Diagenetically Replaced Carbonate Rock
Published: 2020-05-25
Subjects: Biogeochemistry, Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics, Planetary Geology, Planetary Sciences
Stromatolites have been a major focus in the search for ancient microbial life, however, the organic carbon biosignatures of dolomitized stromatolites have not yet been fully characterized or correlated with their dolomitizing conditions. Although dolomitization rarely preserves microbial morphology, the presence of organic carbon can provide valuable information for characterization of fossils’ [...]
Fault-controlled base-of-scarp deposits
Published: 2020-05-24
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Sedimentology
The term base-of-scarp is proposed for those submarine deposits controlled by a fault and physically disconnected from their more proximal counterpart located on the footwall, although genetically linked to it. These systems differ from conventional fault-controlled deltas, such as shoal- and Gilbert-type, because they are entirely subaqueous and lack equilibrium morphology — a steady-state in [...]
Influence of Minibasin Obstruction on Canopy Dynamics in the northern Gulf of Mexico
Published: 2020-05-17
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
In salt-detached gravity-gliding/spreading systems the detachment geometry is a key control on the downslope mobility of the supra-salt sequence. Here we used regional 3D seismic data to examine a salt-stock canopy in the northern Gulf of Mexico slope, in an area where supra-canopy minibasins subsided vertically and translated downslope above a complex base-of-salt. If thick enough, minibasins [...]
Three Common Statistical Missteps We Make in Reservoir Characterization
Published: 2020-05-11
Subjects: Chemical Engineering, Earth Sciences, Engineering, Geology, Petroleum Engineering, Physical Sciences and Mathematics, Statistical Methodology, Statistics and Probability
Reservoir characterization analysis resulting from incorrect applications of statistics can be found in the literature, particularly in applications where integration of various disciplines is needed. Here, we look at three misapplications of ordinary least squares linear regression (LSLR) and show how they can lead to poor results and offer better alternatives, where available. The issues are [...]
Unmixing and mapping components of Northern Ireland’s geochemical composition using FastICA and random forests
Published: 2020-05-07
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics
There is an increasing trend for the collection of multi-sensory quantitative data to support the mapping of geology and environment. In the United Kingdom and Ireland this trend has been led by the Tellus mapping programmes; large scale multidisciplinary surveys which have collected quantitative data by a combination of geophysical survey from the air and geochemical survey on the ground. Such [...]
The timing of magmatism and subsequent alteration of basaltic rocks cored at the base of IODP Site U1513, Naturaliste Plateau, southwestern Australia
Published: 2020-05-07
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics
An 82.2 m thick sequence of basaltic rocks was recovered from a deep-sea core on the eastern flank of the Naturaliste Plateau, offshore southwestern Australia during International Ocean Discovery Program (IODP) Expedition 369. The basaltic rocks were cored at the base of IODP Site U1513 and represent the acoustic basement of the Mentelle Basin. The recovered materials consist of subaerial to [...]
Constraining crustal silica on ancient Earth
Published: 2020-05-06
Subjects: Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics
Accurately quantifying the composition of continental crust on Hadean and Archean Earth is critical to our understanding of the physiography, tectonics, and climate of our planet at the dawn of life. One longstanding paradigm involves the growth of a relatively mafic planetary crust over the first 1-2 billion years of Earth history, implying a lack of modern plate tectonics, a paucity of [...]
Connecting the Deep Earth and the Atmosphere
Published: 2020-04-30
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics
Most hotspots, kimberlites, and large igneous provinces (LIPs) are sourced by plumes that rise from the margins of two large low shear-wave velocity provinces in the lowermost mantle. These thermochemical provinces have likely been quasi-stable for hundreds of millions, perhaps billions of years, and plume heads rise through the mantle in about 30 Myr or less. LIPs provide a direct link between [...]
Structure and kinematics of an extensional growth fold, Hadahid Fault System, Suez Rift, Egypt
Published: 2020-04-29
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
Normal faulting drives extensional growth folding of the Earth’s upper crust during continental extension, yet we know little of how fold geometry relates to the structural segmentation of the underlying fault. We use field data from the Hadahid Fault System, Suez Rift, Egypt to investigate the geometry and kinematics of a large (30 km long, up to 2.5 km displacement), exceptionally well exposed [...]
Quantitative analysis of a footwall-scarp degradation complex and syn-rift stratigraphic architecture, Exmouth Plateau, NW Shelf, offshore Australia
Published: 2020-04-29
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics
Interactions between footwall-, hangingwall- and axial-derived depositional systems make syn-rift stratigraphic architecture difficult to predict, and preservation of net-erosional source landscapes is limited. Distinguishing between deposits derived from fault-scarp degradation (consequent systems) and those derived from long-lived catchments beyond the fault block crest (antecedent systems) is [...]
Using thermal springs to quantify deep groundwater flow and its thermal footprint in the Alps and North American orogens
Published: 2020-04-29
Subjects: Earth Sciences, Geology, Hydrology, Physical Sciences and Mathematics
The extent of deep groundwater flow in mountain belts and its thermal effects are uncertain. Here, we use a new database of discharge, temperature and composition of thermal springs in the Alps to estimate the extent of deep groundwater flow and its contribution to the groundwater and heat budget. The results indicate that springs are fed exclusively by meteoric water and make up 0.1% of the [...]
Lateral variability in strain along a mass-transport deposit (MTD) toewall: a case study from the Makassar Strait, offshore Indonesia
Published: 2020-04-18
Subjects: Earth Sciences, Geology, Geomorphology, Physical Sciences and Mathematics, Sedimentology
Contractional features characterise the toe domain of mass-transport deposits (MTDs). Their frontal geometry is typically classified as frontally-confined or frontally-emergent. However, it remains unclear how frontal emplacement style and contractional strain within an MTD can vary along strike. We use bathymetry and 3D seismic reflection data to investigate lateral variability of frontal [...]
Recognizing fracture pattern signatures contributed by seismic loadings
Published: 2020-04-14
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure
The impacts of seismic loadings to fault zone rocks are still not well understood. While field and experimental studies have suggested several markers, such as pseudotachylytes and pulverized rocks, for indicating seismic loadings, the corresponding markers of other types or at larger scales are still lacking. Here by summarizing results of dynamic ruptures with off-fault damage, we recognize [...]