bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantifying the Effects of Salt Structures on Source Rocks Thermal Evolution of the Marine Sedimentary Basins
Authors: Liu Shaowen , Wang Liangshu
Published: March 2020

Evaporitic salt is prevailed in marine sedimentary basins, and the discovered hydrocarbon reservoirs are generally associated with salt structures in the world; accordingly salt structures have attracted much attention from academic and industry during the past decade. Tarim Basin that locates in northwest China, is the largest marine sedimentary basin in China with great hydrocarbon resources potential. Previous studies of salt structures in this basin mainly focus on its strong sealing capacity and structural traps created by salt structures. However, besides its extreme impermeability and low viscosity, rock salt has another unique thermal properties, featured by a large thermal conductivity as high as 5~6 W/(m.K), usually 2~3 times greater than that of other common sedimentary rocks, but a relatively low radiogenic heat production. This strong contrast in thermal properties could change the evolving thermal regime and associated thermal history of the source rocks around salt bodies, but has not been understood well. Herein based on the theoretical models and interpreted salt bearing seismic profiles from the Kuqa Foreland Basin, northern Tarim Basin, we use the 2D finite element numerical experiments to investigate the impacts of salt structures on basin geothermal regime and associated hydrocarbon thermal evolution. Our results show that, owing to its high efficiency in heat conduction, the salt rocks would result in obviously positive temperature anomalies (3~13%) above the salt body and negative temperature anomalies (11~35%) in the subsalt, enhancing and restraining the thermal maturation of source rocks above and below the salt body, respectively. The amplitude and extent of geothermal effects of salt structures depend on the thermal conductivity, geometry, thickness and burial depth of the salt bodies. The thermally affected area around the salt body can be 2 time of salt radius laterally and 2~3 times of salt thickness vertically. Salt structures in the Kuqa Foreland Basin can prominently cool the subsalt formation temperature and accordingly reduce the thermal maturity (Ro) of Jurassic source rocks as much as 18%, enabling the source rocks to be still of gas generation other than over-mature stage as expected previously, which is favor for deep hydrocarbon preservation below salt. In particular, salt structures in the west and east Kuqa Foreland Basin show strong differences in their thickness, geometric pattern, burial depth and composition, the thermal effects of salt structures on thermal maturation of subsalt source rocks should differ accordingly, which is supported by the observed tempo-spatial variation of Ro for Jurassic source rocks in this basin. Finally, we propose that the geothermal effects of salt structures will be of great importance in the deep hydrocarbon resources potential assessment and exploration in marine sedimentary basins in China.
Holocene moisture variations in western arid central Asia inferred from loess records from NE Iran
Authors: Wang Qiang , Wei Haitao , Khormali Farhad , Wang Leibin , Xie Haichao , Wang Xin , Huang Wei , Chen Jianhui , Chen Fahu
Published: March 2020

Holocene variations in precipitation in central and eastern arid central Asia (ACA) have been widely investigated, but the pattern in western ACA remains unclear. We present records of the stable carbon isotope composition of bulk organic matter (δ13Corg), magnetic parameters, and sediment color, from five loess-paleosol sequences in NE Iran, in western ACA, with the aim of reconstructing Holocene precipitation. The Yellibadragh (YE) section (the thickest among the five sequences) was selected for OSL dating of the coarse-grained quartz (63-90 μm) fraction, and its δ13Corg record was used to quantitatively reconstruct mean annual precipitation (MAP). The record indicates a dry early Holocene (~11.8-7.4 ka), with nearly constant MAP (~93 mm), followed by a wetting trend from the mid-Holocene (~7.4 ka) onwards, with the wettest period in the late Holocene (~4.0-0.0 ka, ~390 mm). The stratigraphic observations and environmental proxies support the reconstruction. The other loess profiles show stratigraphic features and trends of environmental proxies which are similar to those of the YE profile. A dry early Holocene and wetting trend since the mid-Holocene, with the wettest climate in the late Holocene in NE Iran, are both consistent with records from sand dunes and lake sediments from adjacent areas, and with loess records from central and eastern ACA. Comparison with loess records from monsoonal Asia supports the interpretation of a “westerlies-dominated climatic regime” (WDCR) which was proposed mainly on the basis of lake sediment records from the region. Changes in solar insolation may have been responsible for the persistent wetting trend during the Holocene in western ACA.
Biogeochemical processes in continental slope sediments of the Dongsha Area, South China Sea
Authors: Sun Tiantian , Wu Daidai , Ye Ying
Published: March 2020

Serving as an indicator or fluid seepage from seabed sediments, cold seeps are ubiquitous along continental margins worldwide. In this study, a 14 m long sediment core (# 973-4) from the Dongsha Area on the northern continental slope of the South China Sea, was investigated to trace the cold seep activity and sedimentary paleo-environmental changes and its consequence for sediment mineralogy, contents of major and trace elements, total organic and inorganic carbon and total TRIS (total reducible inorganic sulfur) and δ34S of sulfide minerals. In addition, planktonic foraminifera were selected for accelerator mass spectrometer carbon 14 (AMS14C) dating [1]. Furthermore, we identified the strength and effects of cold seep activity and its impact on the underlying seawater redox condition, and finally elucidated the derived force and paleoenvironment constraints of cold seep activity. C-S-Fe geochemistry, δ34S of sulfide minerals and major and trace elements suggest that anaerobic oxidation of methane (AOM) occurred at 619-900 cmbsf (centimeters below seafloor). The 34S enrichments (up to 23.6 ‰), abundant TRIS contents, high S/C ratios close to the seawater, together with high enrichments of Mo indicate temporal sulfidic methane seep events. Lithological distribution and AMS14C dating of planktonic foraminifera show that a turbidite (~35ka) is related to a foram-rich interval (440-619 cm) and increased carbonate productivity during the Last Glacial Maximum (LGM). An enrichment of Mo and U was observed accompanied by low contents of other trace and major (Al, Ti, V, Ni, Fe, Mn and Cu) in this interval. The foram-rich interval of cold seep sediments was probably linked to the phenomenon of inconsecutive sedimentary sequence due to the turbidites, which resulted in the lack of Fe, Mn and Ba. Based on the new results, it can be speculated that this area has experienced several episodes of methane seep activity and aerobic oxidation occurring alternatively in the last glacial period which may have been caused by fluctuating non-steady conditions. Further exploration of AOM should focus on the impact of rapid deposition, especially the impact of turbidites on sedimentary biogeochemical processes.

[1] Zhang Bidong, Pan Mengdi, Wu Daidai etc. Distribution and isotopic composition of foraminifera at cold-seep Site 973-4 in the Dongsha area, northeastern South China Sea. J. Asian Earth Sciences.

 

The research supported by the Institution of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences (no. ISEE2018YB03) and the special project for marine economy development of Guangdong Province (no. GDME-2018D002).
Spring Snowmelt Flood Estimate in the Upper Heihe River under Climate Change Scenarios
Authors: Zhu Guangxi
Published: March 2020

With the climate warming, high mountainous areas, including cryosphere, show more frequent and early outbreaks trend in flood hazard, cursing more losses to downstream areas. Based on meteorological, hydrological and MODIS snow cover data, using the snowmelt runoff model (SRM) to simulate and verify the spring runoff result during the snowmelt period from 1990 to 2012 in the upper Heihe River. SRM model simulates results shows it has a high accuracy (NSE = 0.7229), which can be used to predict the future flood intensity changes in studying area. In order to predict the trends of Heihe River Basin in flood return periods under the different future climate change scenarios, analyze used the temperature and precipitation forecast data. By the end of this century, the result of flood runoff shows differently according to climate change scenarios compared with the basic period. In RCP 2.6, due to the small changes of the temperature and precipitation, flood intensity will change slightly around 10% in all return periods; in RCP 4.5, it will increase about 20%; in RCP 8.5, return periods may be rise over 30%.
Interactions between agricultural mulching plastic debris and pesticides
Authors: Beriot Nicolas , Zomer Paul , Zornoza Raul , Geissen Violette Geissen
Published: March 2020

In semi-arid regions, the use of plastic mulch and pesticides in conventional agriculture is nearly ubiquitous. The use of plastics and pesticides lead both to the release of residues in the soils. The degradation of plastic and pesticide residues in the soil have been previously studied, but not together despite the fact that pesticides may be sorbed to plastics and that the sorption may change the degradation rate. In fact, the sorption of pesticides on Low Density Polyethylene (LDPE) has been previously  studied, but no data is available for other plastics such as Pro-oxidant Additive Containing (PAC) plastics or “biodegradable” (Bio) plastics. The aim of this research was to measure the sorption pattern of active substances from 38 pesticides on LDPE, PAC and Bio plastic mulches and to compare the decay of the active substances in the presence and absence of plastic debris. For this purpose, 38 active substances from 17 insecticides, 15 fungicides and 6 herbicides commonly applied with plastic mulching in South-east Spain were incubated at 35°C for 15 days with a 3×3 cm² square of plastic mulch (LDPE, PAC and Bio). The QuEChERS (Quick Easy Cheap Effective Rugged Safe) approach was adapted to extract the pesticides. The sorption behaviour depended on both, the pesticide and the plastic mulch type. On average, the sorption percentage was ~23% on LDPE and PAC, and ~50% on Bio. The decay of active substances in the presence of plastic was, on average, 30% lower than the decay of active substances in solution alone. Therefore, efficacy, transport, degradability and/or eco-toxicity of active substances from pesticides may be affected by sorption on plastics. Additionally the sorption of pesticides on plastic debris may affect the plastic degradability due to the toxicity of pesticides to some soil organisms.

 
Effects of conversion from vineyard to tree plantation on humus forms, soil organic carbon stock and other soil properties
Authors: Ferré Chiara , Facciotto Gianni , Bergante Sara , Comolli Roberto
Published: March 2020

We explored the effects of conversion from vineyard to tree plantation on humus forms, soil organic carbon (SOC) stocks and other soil properties by sampling paired plots in a hilly area of Monferrato (Piedmont, Italy).

The study area is located at Rosignano Monferrato (AL) and includes a vineyard (VY) and a nearby 30-years-old tree plantation (TP) for wood production that replaced an existing vineyard, where eight poplar clones were consociated with other timber species (wild cherry, European ash, manna ash, deodar cedar). The area under study covers 3 ha and extends along a slighty-wavy slope with an average gradient of 15%; according to the WRB classification, soils are Calcaric Cambisols (Loamic).

The impact of land use change on soil properties was evaluated considering the spatial variability of soil characteristics, testing for autocorrelation among the model residuals. Soil sampling was performed from 3 layers (0-10 cm, 10-40 cm and 40-70 cm) at 61 and 69 points in the VY and the TP respectively, to characterize soil pH in water, organic carbon content and SOC stock, C:N ratio, soil texture and total carbonates. The common pedological origin of soils within the study area was verified and confirmed by comparability of soil texture and carbonates content of the deeper layer.

At TP the humus forms were described and classified; the organic horizons were sampled and analyzed for OC content determination.

Statistical analyses showed significant (p-value < 0.05) differences for all the investigated layers between the considered land uses with regard to pH, SOC stock and C:N ratio.

Our study provided evidence that: (1) the conversion from vineyard to tree plantation resulted in the appearance of organic horizons: the main humus forms in TP were Mull and Amphi; (2) 30 years of tree plantation strongly modified SOC stock, resulting in an increase of 26% in the first 70 cm, which became 42% if the organic layers were included; (2) soil acidification (pH difference of 0.4) and change in SOC type (C:N increase of 1) were also observed in TP compared to VY; and (3) the spatial distribution of soil properties in the VY were affected by erosive and depositional dynamics unlike the TP where vegetation counterbalance erosion.
Multi-scale assimilation of SMAP data: comparison between land surface and land surface-subsurface model
Authors: Zhao Haojin , Baatz Roland , Montzka Carsten , Vereecken Harry , Hendricks Franssen Harrie-Jan
Published: March 2020

Soil moisture plays an important role in the coupled water and energy cycles of the terrestrial system. However, the characterization of soil moisture at the large spatial scale is far from trivial. To cope with this challenge, the combination of data from different sources (in situ measurements by cosmic ray neutron sensors, remotely sensed soil moisture and simulated soil moisture by models) is pursued. This is done by multiscale data assimilation, to take the different resolutions of the data into account. A large number of studies on the assimilation of remotely sensed soil moisture in land surface models has been published, which show in general only a limited improvement in the characterization of root zone soil moisture, and no improvement in the characterization of evapotranspiration. In this study it was investigated whether an improved modelling of soil moisture content, using a simulation model where the interactions between the land surface, surface water and groundwater are better represented, can contribute to extracting more information from SMAP data. In this study over North-Rhine-Westphalia, the assimilation of remotely sensed soil moisture from SMAP in the coupled land surface-subsurface model TSMP was tested. Results were compared with the assimilation in the stand-alone land surface model CLM. It was also tested whether soil hydraulic parameter estimation in combination with state updating could give additional skill compared to assimilation in CLM stand-alone and without parameter updating. Results showed that modelled soil moisture by TSMP did not show a systematic bias compared to SMAP, whereas CLM was systematically wetter than TSMP. Therefore, no prior bias correction was needed in the data assimilation. The results illustrate how the difference in simulation model and parameter estimation result in significantly different estimated soil moisture contents and evapotranspiration.  
Bridging the gap between the terrestrial and marine paleoclimate reconstructions in the North Atlantic realm
Authors: Nilsen Tine , Luterbacher Jürg
Published: March 2020

Climate field reconstruction (CFR) techniques have become common tools for studying terrestrial climate variability across various time and space scales1,2. Here, we present the framework of ensemble-based CFR of sea surface temperature in the North Atlantic Ocean, using a Bayesian hierarchical model5 and the proxy surrogate reconstruction method6. Methodological development is necessary in order to take properly into account the age-depth uncertainties that is specific to proxies originating from marine sediment cores, and the generally low temporal resolution of the data. The new reconstructions will provide evidence on linkages and mechanisms between the marine realm and European climate including extremes covering the past 2000 years. The spatiotemporal covariance-structures of the input and output data are of special relevance, and the benchmarking datasets can be used for various impact studies and for paleomodel/data comparison and process understanding coupling the North Atlantic with Eurasia.

 

References:

1Luterbacher, J. & Zorita, E. in “The Palgrave Handbook of Climate History”, (2018), Palgrave Macmillan, Springer Nature Limited,London, 131-140, ISBN 978-1-137-43020-5 (eBook), doi: 10.1057/978-1-137-43020-5

2Neukom, R. et al. (2019), Nature, 571, 550–554, doi:10.1038/s41586-019-1401-2

3 Tingley, M. P. and P. Huybers (2010a), J. Clim., 23, 2759–2781, doi: 10.1175/2009JCLI3015.1

4 Graham, N.E. et al. (2007), Clim. Change, 83, 241-285, doi: 10.1007/s10584-007-9239-2
Integrating Deep Learning to GIS Modelling: An Efficient Approach to Predict Sediment Discharge at Karstic Springs Under Different Land-Use Scenarios
Authors: Patault Edouard , Landemaine Valentin , Ledun Jérôme , Soulignac Arnaud , Fournier Matthieu , Ouvry Jean-François , Cerdan Olivier , Laignel Benoit
Published: March 2020

Sediment Discharge (SD) at karstic springs refers to a black-box due to the non-linearity of the processes generating SD, and the lack of accurate physical description of karstic environments. Recent research in hydrology emphasized the use of data-driven techniques for black-box models, such as Deep Learning (DL), considering their good predictive power rather than their explanatory abilities. Indeed, their integration into traditional hydrology-related workflows can be particularly promising. In this study, a deep neural network was built and coupled to an erosion-runoff GIS model (WATERSED, Landemaine et al., 2015) to predict SD at a karstic spring. The study site is located in the Radicatel catchment (88 km² in Normandy, France) where spring water is extracted to a Water Treatment Plant (WTP). SD was predicted for several Designed Storm Project (DSP0.5-2-10-50-100) under different land-use scenarios by 2050 (baseline, ploughing up 33% of grassland, eco-engineering (181 fascines + 13ha of grass strips), best farming practices (+20% infiltration)). Rainfall time series retrieved from French SAFRAN database and WATERSED modelling outputs extracted at connected sinkholes were used as input data for the DL model. The model structure was found by a classical trial and error procedure, and the model was trained on two significant hydrologic years (nevents = 731). Evaluation on a test set suggested good performance of the model (NSE = 0.82). Additional evaluation was performed comparing the ‘Generalized Extreme Value’ (GEV) distribution for the five DSP under the baseline scenario. The SD predicted by the DL model was in perfect agreement with the GEV distribution (R² = 0.99). Application of the model on the other scenarios suggests that ploughing up 33% of grasslands will increase SD at the WTP to an average 5%. Eco-engineering and best farming practices will reduce SD in the range of 10-44% and 63-80% respectively. This novel approach offers good opportunities for SD prediction at karstic springs or WTP under multiple land use scenarios. It also provide robust decision making tools for land-use planning and drinking water suppliers.
A systematic study of OH in hydrous pyrope-grossular garnets
Authors: Chang Yun-Yuan , Huang Yu-Chin , Kung Jennifer
Published: March 2020

Garnet is a common mineral in crustal metamorphic rocks and a primary constituent of the Earth’s upper mantle. Natural silicate garnets are stable over a wide range of pressure and temperature conditions and have very complex chemical compositions. The chemical composition of a natural garnet reflects its growth environment making garnet a critical indicator mineral for many geological processes. Garnet, like olivine and many other nominally anhydrous minerals, can incorporate water as hydroxyl (OH-) into its crystal structure. The water content in natural silicate garnets ranges from almost dry to thousands of parts per million. The compositional effect on the water content and the mechanisms of OH- incorporation in silicate garnets are not well understood, majorly impeded by their complex compositions. Here we reported the influence of chemical compositions on the water content and OH- substitution mechanisms in silicate garnets by studying synthetic garnet samples with compositions in the pyrope-grossular solid solution. We synthesized a series of hydrous pyrope-grossular garnets with various magnesium to calcium ratios by a multi-anvil press. Fourier transform infrared spectroscopy and Raman spectroscopy were applied to characterize the OH- content and identify OH- substitution mechanisms in the synthetic samples. The influence of hydration on the crystal structure of samples was investigated by the single-crystal X-ray diffraction technique. Our experimental results will help to constrain the bulk water content in the Earth’s interior and to interpret seismic data of a hydrous mantle. 

 