Preprints
There are 6976 Preprints listed.
A Short Note on the Age of the Marwar Supergroup, NW India
Published: 2021-05-23
Subjects: Earth Sciences
We report a summary of geochronological data derived from detrital zircons in the Marwar Supergroup, Rajasthan, India. Although the age of deposition for the Marwar sequence was inferred to be post-Cryogenian, there is a lack of any direct age data. Two recent papers reached different conclusions based on geochronological data. A Rb-Sr age on a felsic flow within the Sonia sandstone yielded [...]
High-resolution petrographic evidence confirming detrital and biogenic magnetites as remanence carriers for Zongpu carbonates in the Gamba area, South Tibet
Published: 2021-05-26
Subjects: Earth Sciences
Paleocene carbonates from the Gamba area of South Tibet provide the largest paleomagnetic dataset for constraining the paleogeography of the India-Asia collision in the early stage. The characteristic remanences (ChRMs) obtained from this unit were, however, argued for a chemical remagnetization via orogenic fluids. This study carries out a high-resolution petrographic study on the Paleocene [...]
Simulating land use change trajectories of the Cerrado Hotspot reveals the importance of considering private property sizes for biodiversity conservation
Published: 2021-05-24
Subjects: Life Sciences
Simulating future land use changes can be an important tool to support decisionmaking, especially in areas that are experiencing rapid anthropogenic pressure, such as the Cerrado – Brazilian savanna. Here we used a spatially-explicit model to identify the main drivers of native vegetation loss in the Cerrado, and then projected this loss for 2050 and 2070. We also analyzed the role of [...]
Defining a Sustainable Development Target Space for 2030 and 2050
Published: 2021-05-24
Subjects: Environmental Indicators and Impact Assessment, Environmental Monitoring, Environmental Sciences, Environmental Studies, Natural Resource Economics, Other Environmental Sciences, Physical Sciences and Mathematics, Social and Behavioral Sciences, Sustainability
By adopting the Sustainable Development Goals (SDGs), countries worldwide agreed to an agenda for achieving a prosperous, socially inclusive and environmentally sustainable future for all1. This ambition, however, also exposes a critical knowledge gap since science-based insights on how to achieve the 17 SDGs simultaneously are lacking. Quantitative goal-seeking scenario studies could enable [...]
Quantifying the influence of conduit inclination on Taylor Bubble behaviour in basaltic magmas.
Published: 2021-05-27
Subjects: Earth Sciences, Physical Sciences and Mathematics, Volcanology
The ascent of single Taylor bubbles suspended in a range of Newtonian liquids, scaled to mimic basaltic magmas, within vertical and inclined tubes has been studied experimentally over the range 0° to 70° (where 0° is vertical and 90° is horizontal). Using measurements of Taylor bubble parameters (ascent velocity and film thickness) and morphology, alongside dimensionless numbers, we show that [...]
Photochemical synthesis of ammonia and amino acids from nitrous oxide
Published: 2021-05-26
Subjects: Life Sciences
Abiotic synthesis of ammonia and amino acids are important for origin of life and early evolution. Ammonia (NH3) and organic nitrogen species may be possibly produced from nitrous oxide (N2O), which is a second abundant nitrogen species in the atmosphere. Here, we report a new photochemical experiment and evaluate whether N2O can be used as a nitrogen source for prebiotic synthesis in the [...]
A radial hydraulic fracture driven by a Herschel–Bulkley fluid
Published: 2021-05-27
Subjects: Fluid Dynamics, Hydraulic Engineering, Hydrology, Numerical Analysis and Scientific Computing, Oil, Gas, and Energy, Volcanology
We analyse the influence of fluid yield stress on propagation of a radial (penny-shaped) hydraulic fracture in a permeable reservoir. In particular, the Herschel-Bulkley rheological model is adopted that includes yield stress and non-linearity of the shear stress. The rock is assumed to be linear elastic, and the fracture is driven by the point source fluid injection with a constant volumetric [...]
Uncertainty analysis in machine learning for lithofacies classification and porosity prediction
Published: 2021-05-27
Subjects: Engineering, Physical Sciences and Mathematics
Recently, machine learning has been widely and successfully used by geoscientists to solve typical inverse problems. However, the uncertainty related to the learned model is not properly analysed, and sometimes a simple activation function is applied to provide posterior probability. To address this problem, variance of machine learning models is calculated that can provide additional information [...]
Non-stationary analysis of rogue wave probability over a shoal
Published: 2021-05-27
Subjects: Engineering, Physical Sciences and Mathematics
Non-equilibrium evolution of wave fields, as occurring over sudden bathymetry variations, can produce rogue seas with anomalous wave statistics. We handle this process by modifying the Rayleigh distribution through the energetics of second-order theory and a weakly non-stationarity reformulation of the Khintchine theorem. The probability model in unsteady conditions is then probed against [...]
Quantifying the impact of lagged hydrological responses on the effectiveness of groundwater conservation
Published: 2021-05-27
Subjects: Earth Sciences, Hydrology, Physical Sciences and Mathematics
Many irrigated agricultural areas seek to prolong the lifetime of their groundwater resources by reducing pumping. However, it is unclear how lagged responses, such as reduced groundwater recharge caused by more efficient irrigation, may impact the long-term effectiveness of conservation initiatives. Here, we use a variably saturated, simplified surrogate groundwater model to: 1) analyze aquifer [...]
An occurrence of radially-symmetric sedimentary structures in the basal Ediacaran cap dolostone (Keilberg Member) of the Otavi Group
Published: 2021-06-02
Subjects: Life Sciences, Physical Sciences and Mathematics
Snowball Earth cap carbonate sequences provide an archive of what are likely the most dramatic climate transitions in all of Earth history. One approach to gain insight into these events is the detailed observation of sedimentary structures within these post-glacial units. Here, we report on newly discovered radially-symmetric sedimentary structures within the Keilberg Member post-Marinoan ‘cap [...]
ANALYSIS OF OWNER DRIVEN APPROACH OF HOUSING RECONSTRUCTION AFTER GORKHA EARTHQUAKE 2015: A CASE STUDY OF DHUNIBESHI MUNICIPALITY, DHADING
Published: 2021-05-26
Subjects: Engineering
A 7.6 magnitude earthquake occurred in Gorkha district of Nepal leading more than 9,000 estimated casualties, approximately 23,000 injuries and damages on more than half a million structures. For leading and managing the earthquake recovery and reconstruction in Nepal, a legally mandated agency named National Reconstruction Authority (NRA) was established in December 2015 which facilitate and [...]
Detection of Interannual Ensemble Forecast Signals over the North Atlantic and Europe using Atmospheric Circulation Regimes
Published: 2021-05-27
Subjects: Applied Mathematics, Atmospheric Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
To study the forced variability of atmospheric circulation regimes, the use of model ensembles is often necessary for identifying statistically significant signals as the observed data constitute a small sample and are thus strongly affected by the noise associated with sampling uncertainty. However, the regime representation is itself affected by noise within the atmosphere, which can make it [...]
Projecting long-term armed conflict risk: an underappreciated field of inquiry?
Published: 2021-05-27
Subjects: Environmental Studies, Human Geography, Nature and Society Relations, Social and Behavioral Sciences
Little research has been done on projecting long-term conflict risks in response to climate change. Such projections are currently neither included in the development of socioeconomic scenarios or climate change impact assessments nor part of global agenda-setting policy processes. In contrast, in other fields of inquiry, long-term projections and scenario studies are established and relevant for [...]
Non-deterministic effects in modelling the tidal currents in a high-energy coastal site
Published: 2021-05-27
Subjects: Environmental Sciences, Oceanography
Numerical models are commonly employed for predicting tidal stream resource, since harmonic analysis is typically insufficient for representing tidal currents. This is particularly true in regions of high-energy flow and complex bathymetric and coastline features, resulting in highly nonlinear dynamics. Within this work, we demonstrate that non-deterministic effects pose a further barrier to [...]