Comptes Rendus Geoscience最新文献_第9页

Petrogenesis and tectonic significance of mafic-ultramafic rocks from southwestern Yunnan, China 滇西南镁铁质-超镁铁质岩石的成因及构造意义

IF 1.4 4区地球科学

Comptes Rendus Geoscience Pub Date : 2019-06-01 DOI: 10.1016/j.crte.2019.04.004

Qing Shi, Nianqiao Fang

引用次数: 2

Page de Sommaire Page de Sommaire

IF 1.4 4区地球科学

Comptes Rendus Geoscience Pub Date : 2019-06-01 DOI: 10.1016/S1631-0713(19)30086-0

引用次数: 0

Progradation and retrogradation of the Medjerda delta during the 20th century (Tunisia, western Mediterranean) 20世纪Medjerda三角洲的退化与发展(西地中海突尼斯)

IF 1.4 4区地球科学

Comptes Rendus Geoscience Pub Date : 2019-04-01 DOI: 10.1016/j.crte.2018.10.004

Thouraya Ben Moussa , Oula Amrouni , Abderraouf Hzami , Laurent Dezileau , Gil Mahé , Saâdi Abdeljaouad

{"title":"Progradation and retrogradation of the Medjerda delta during the 20th century (Tunisia, western Mediterranean)","authors":"Thouraya Ben Moussa , Oula Amrouni , Abderraouf Hzami , Laurent Dezileau , Gil Mahé , Saâdi Abdeljaouad","doi":"10.1016/j.crte.2018.10.004","DOIUrl":"10.1016/j.crte.2018.10.004","url":null,"abstract":"<div>The aim of this study is the reconstitution of the recent morpho-sedimentary evolution of the Medjerda River delta. We examine the spatio-temporal evolution of the Medjerda shoreline between 1936 and 2016 using satellite images, complemented by sedimentological and geochemical analyses and 210Pbex and 137Cs radiometric data. The general tendency of the shoreline evolution shows an increasing progradation (300 ± 12 m) between 1936 and 2016. Yet the mesoscale Net Shoreline Movement position (NSM) and the End Point Rate (EPR) reveal an erosion pattern estimated to be −20 m ± 0.15 m/yr during the period 1988–1999.The sedimentological analyses reveal four main lithostratigraphic units. The fine sand substratum layer (Md = 0.08 mm) decreases toward clay and silt facies (Md < 0.063 mm), rich in continental plant debris. The geochemical results reveal gradual incoming of the terrigenous component instead of marine deposits. The 137Cs/210Pbex radiometric dating confirms the functioning of the new river flow by the 1950s with the highest sedimentation rate being 3.3 cm/yr. Our results show that the Sidi-Salem dam impoundment (1981) led to a dramatic reduction of sediment discharge, a decrease of the grain size with nearly no more sand reaching the coast, and the shoreline retreat.</div>","PeriodicalId":50651,"journal":{"name":"Comptes Rendus Geoscience","volume":"351 4","pages":"Pages 340-350"},"PeriodicalIF":1.4,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.crte.2018.10.004","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42932007","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 15

Page de Sommaire 目录页

IF 1.4 4区地球科学

Comptes Rendus Geoscience Pub Date : 2019-04-01 DOI: 10.1016/S1631-0713(19)30064-1

引用次数: 0

The ore genesis of the Jebel Mecella and Sidi Taya FBa (ZnPb) Mississippi Valley-type deposits, Fluorite Zaghouan Province, NE Tunisia, in relation to Alpine orogeny: Constraints from geological, sulfur, and lead isotope studies 突尼斯Zaghouan省Jebel Mecella和Sidi Taya FBa (ZnPb)密西西比河谷型矿床与高山造山作用的关系:来自地质、硫和铅同位素研究的约束

IF 1.4 4区地球科学

Comptes Rendus Geoscience Pub Date : 2019-04-01 DOI: 10.1016/j.crte.2018.11.006

Nejib Jemmali , Larbi Rddad , Fouad Souissi , Emmanuel John M. Carranza

{"title":"The ore genesis of the Jebel Mecella and Sidi Taya FBa (ZnPb) Mississippi Valley-type deposits, Fluorite Zaghouan Province, NE Tunisia, in relation to Alpine orogeny: Constraints from geological, sulfur, and lead isotope studies","authors":"Nejib Jemmali , Larbi Rddad , Fouad Souissi , Emmanuel John M. Carranza","doi":"10.1016/j.crte.2018.11.006","DOIUrl":"10.1016/j.crte.2018.11.006","url":null,"abstract":"<div>Jebel Mecella and Sidi Taya F–(Ba<img>Pb<img>Zn) deposits are located within the Fluorite Zaghouan Province (NE Tunisia). The mineralization occurs along the unconformity surface between the Jurassic limestones and Upper Cretaceous rocks. The mineralization consists mainly of fluorite, barite, sphalerite, and galena. The δ34S values of barite at Jebel Mecella (14.8–15.4‰) and at Sidi Taya (21.6–22.2‰) closely match those of the Triassic evaporites and Messinian seawater, respectively. The range of δ34S values of galena and sphalerite in both deposits (−6.9 to +2.4‰) suggests the involvement of thermochemical sulfate reduction and possibly organically-bound sulfur in the generation of sulfur. Lead isotope data with 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb ratios of 18.893–18.903, 15.684–15.699, and 38.850–38.880, respectively suggests a single homogeneous source reservoir of Paleozoic age and/or the homogenization of the Paleozoic–Cretaceous multireservoir-derived fluids along their long migration paths to the loci of deposition during the Alpine orogeny.</div>","PeriodicalId":50651,"journal":{"name":"Comptes Rendus Geoscience","volume":"351 4","pages":"Pages 312-320"},"PeriodicalIF":1.4,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.crte.2018.11.006","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43868665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 5

Mapping of aboveground biomass in Gabon 加蓬地上生物量制图

IF 1.4 4区地球科学

Comptes Rendus Geoscience Pub Date : 2019-04-01 DOI: 10.1016/j.crte.2019.01.001

Mohammad El Hajj , Nicolas Baghdadi , Nicolas Labrière , Jean-Stéphane Bailly , Ludovic Villard

{"title":"Mapping of aboveground biomass in Gabon","authors":"Mohammad El Hajj , Nicolas Baghdadi , Nicolas Labrière , Jean-Stéphane Bailly , Ludovic Villard","doi":"10.1016/j.crte.2019.01.001","DOIUrl":"10.1016/j.crte.2019.01.001","url":null,"abstract":"<div>The aim of this paper is to map the aboveground biomass (AGB) in Gabon. First, a random forest (RF) model that relates reference AGB values to remote sensing (RS)-derived variables (mainly radar and optical images) was built, and the significant predictive variables were determined. Second, the built RF model was applied to the significant RS-derived variables to predict AGB across Gabon. The results showed that the overall RMSE (Root Mean Square Error) on the RS-derived AGB map with a spatial resolution of 50 m was 63.3 t/ha (R2 = 0.53).To improve the accuracy of the RS-derived AGB map, the integration of LiDAR data provided by the Geoscience Laser Altimeter System (GLAS) onboard the Ice Cloud and Land Elevation Satellite (ICESat) was investigated. First, an RF model that relates reference AGB values to GLAS-derived metrics and a DEM (Digital Elevation Model) was built. Second, the calibrated RF model was applied to obtain a spatially distributed estimation of AGB (GLAS footprints geolocation) covering forested areas in Gabon, with a density of 0.13 footprints/km2. Third, the semivariogram of residuals (RS-derived AGB map – GLAS-derived AGB “surrogate AGB”) was computed. Later, a regression kriging interpolation was performed by taking into account the spatial structure of residuals to provide a continuous residual map. Finally, the RS-derived AGB map and the residual map were summed, and a final AGB map was obtained. The results showed that the integration of GLAS surrogate AGB data slightly improves the accuracy of the RS-derived AGB map only for AGB values lower than 100 t/ha (bias and RMSE reduced by 13.9 and 10 t/ha, respectively).</div>","PeriodicalId":50651,"journal":{"name":"Comptes Rendus Geoscience","volume":"351 4","pages":"Pages 321-331"},"PeriodicalIF":1.4,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.crte.2019.01.001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47510807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 8

Sur la période des maxima d’activité solaire 在太阳活动高峰期

IF 1.4 4区地球科学

Comptes Rendus Geoscience Pub Date : 2019-04-01 DOI: 10.1016/j.crte.2019.04.001

Jean Malburet

{"title":"Sur la période des maxima d’activité solaire","authors":"Jean Malburet","doi":"10.1016/j.crte.2019.04.001","DOIUrl":"10.1016/j.crte.2019.04.001","url":null,"abstract":"<div>This is the publication of a pli cacheté (sealed letter) submitted to the French Academy of Sciences in 1918 by Jean Malburet (amateur astronomer, 1879–1955). The subject is “On the period of solar activity maxima”. If not reclaimed for 100 years, such sealed letters are opened and analysed by members of the Academy. This letter was considered sufficiently interesting to be published in Comptes rendus Geoscience, along with a descriptive comment of its contents and some of the subsequent history of the ideas put forward in that sealed contribution. In 1918, J. Malburet proposed that “triple syzygies” (alignments) of the planets Jupiter, Venus, and the Earth (with some smaller influence of Mercury) caused tides on the Sun that imposed on our star the observed periodicity (or rather quasi-periodicity) of 11 years. Thanks to contacts with the author’s grandson, two subsequent (1918 and 1925) papers were found, whereas Nicola Scafetta (pers. comm.) pointed out a 1927 criticism of the paper by H.M. Losh. The topic is still an active one today, as witnessed for example by papers by Scafetta, 2012a, Scafetta, 2012b, Scafetta, 2016). The handwritten text of the sealed letter has been typed for easier access to readers and is placed after a short analysis. French has been used throughout this as this is the language of the letter.</div>","PeriodicalId":50651,"journal":{"name":"Comptes Rendus Geoscience","volume":"351 4","pages":"Pages 351-354"},"PeriodicalIF":1.4,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.crte.2019.04.001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47188770","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 5

Mineralogical and seismic properties of serpentinite of Ait Ahmane fault zone of Bou Azzer ophiolite, central Anti-Atlas of Morocco 摩洛哥阿特拉斯中部Bou Azzer蛇绿岩Ait Ahmane断裂带蛇纹岩的矿物学和地震性质

IF 1.4 4区地球科学

Comptes Rendus Geoscience Pub Date : 2019-04-01 DOI: 10.1016/j.crte.2019.01.002

Mohamed Bhilisse , Hassan Admou , Ali Aydda , Lhou Maacha

{"title":"Mineralogical and seismic properties of serpentinite of Ait Ahmane fault zone of Bou Azzer ophiolite, central Anti-Atlas of Morocco","authors":"Mohamed Bhilisse , Hassan Admou , Ali Aydda , Lhou Maacha","doi":"10.1016/j.crte.2019.01.002","DOIUrl":"10.1016/j.crte.2019.01.002","url":null,"abstract":"<div>This paper presents the first seismic measurements of serpentinite of Bou Azzer ophiolite, central Anti-Atlas of Morocco, including seismic velocities and anisotropy. Two serpentinite samples collected from the Ait Ahmane fault zone were analyzed in order to define the mineralogical and seismic features of the natural serpentinite of the Bou Azzer ophiolite. The mineralogical features were investigated using microscopic observation and Raman spectroscopy, while the seismic features were performed using an Electron Backscatter Diffraction (EBSD) instrument. Microscopy and spectroscopy analyses confirmed that the investigated serpentinite suffers from a variable degree of serpentinization, and the antigorite is the dominant variety of serpentine minerals in the study area. The crystal preferred orientation (CPO) results show that the axis [001] of the antigorite deformation is aligned subnormal to the foliation, while the axis [010] is mostly aligned subparallel to the lineation. The seismic anisotropy results are depending on serpentine amount in the rock samples. The sample with a low serpentine amount (30%) shows lowest P- and S-wave anisotropy (Vp = 7.2% and AVs = 6.55%), while the sample with a high amount of serpentine (85%) presents highest P-wave and S-wave anisotropy (Vp = 8.6% and AVs = 11.06%). Consequently, the results indicate that seismic anisotropy increases when increasing the antigorite amount.</div>","PeriodicalId":50651,"journal":{"name":"Comptes Rendus Geoscience","volume":"351 4","pages":"Pages 303-311"},"PeriodicalIF":1.4,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.crte.2019.01.002","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48426143","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Editorial board ENG 编辑委员会

IF 1.4 4区地球科学

Comptes Rendus Geoscience Pub Date : 2019-04-01 DOI: 10.1016/S1631-0713(19)30061-6

引用次数: 0

Optimization approach to retrieve soil surface parameters from single-acquisition single-configuration SAR data 单采集单配置SAR数据反演土壤表面参数的优化方法

IF 1.4 4区地球科学

Comptes Rendus Geoscience Pub Date : 2019-04-01 DOI: 10.1016/j.crte.2018.11.005

Arsalan Ghorbanian, Mahmod Reza Sahebi, Ali Mohammadzadeh

{"title":"Optimization approach to retrieve soil surface parameters from single-acquisition single-configuration SAR data","authors":"Arsalan Ghorbanian, Mahmod Reza Sahebi, Ali Mohammadzadeh","doi":"10.1016/j.crte.2018.11.005","DOIUrl":"10.1016/j.crte.2018.11.005","url":null,"abstract":"<div>This study suggests a novel approach to the retrieval of soil surface parameters using a single-acquisition single-configuration synthetic-aperture radar (SAR) system. Soil surface parameters such as soil moisture and surface roughness are key elements for many environmental studies, including Earth surface water cycles, energy exchange, agriculture, and geology. Remote sensing techniques, especially SAR data, are commonly used to retrieve such soil surface parameters over large areas. Several backscattering models have been proposed for soil surface parameters retrieval from SAR data. However, commonly, these backscattering models require multi configuration SAR data, including multi-polarization, multi-frequency, and multi-incidence angle. Here we propose a methodology that employs single-acquisition single-configuration SAR data for the retrieval of soil surface parameters. The originality is to use single-acquisition single-configuration SAR data to retrieve the soil surface parameters using an optimization approach by the genetic algorithm (GA); we have used the modified Dubois model (MDM) in HH polarization as the backscattering model. Three HH polarization and C band data sets from Quebec (Radarsat-1), Ontario (SIR-C), and Oklahoma (AIRSAR) were analyzed. The retrieved values of soil moisture and soil surface roughness were then compared to ground truth measurements with corresponding parameters. We employed diverse criteria, including the mean absolute error (MAE), the root mean square error (RMSE), the coefficient of performance (CP), and the correlation coefficient to investigate the performance of the proposed methodology. This analysis suggests the capability of the GA for the retrieval of soil surface parameters. Based on our findings, this method presents a viable alternative approach to the retrieval of soil surface parameters when only single-acquisition single-configuration SAR data is available.</div>","PeriodicalId":50651,"journal":{"name":"Comptes Rendus Geoscience","volume":"351 4","pages":"Pages 332-339"},"PeriodicalIF":1.4,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.crte.2018.11.005","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44316057","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 8