Provenance and Paleoclimate of the Triassic to Middle Jurassic Adigrat Sandstone,Blue Nile Basin,Central Ethiopia

作     者：Bekele BARSISA Ayalew DEREJE Kidanemariam GILAMICHAEL Atnafu BALEMWAL Raphaël PIK Bekele BARSISA;Ayalew DEREJE;Kidanemariam GILAMICHAEL;Atnafu BALEMWAL;Raphaël PIK

作者机构：Department of Earth SciencesWollega UniversityNekemteEthiopia Department of Earth SciencesAddis Ababa UniversityAddis AbabaEthiopia Departments of AnthropologyGeography and GeologyEast Los Angeles CollegeLos AngelesCaliforniaUSA CRPG(UMR 7358 CNRS&Universitéde Lorraine)15 rue ND des pauvres BP2054501 Vandoeuvre-Lès-Nancy CedexFrance 

出 版 物：《Acta Geologica Sinica(English Edition)》 (地质学报（英文版）)

年 卷 期：2024年第98卷第4期

页      面：1007-1020页

核心收录：

学科分类：081803[工学-地质工程] 08[工学] 0818[工学-地质资源与地质工程] 

主　　题：mineralogical geochemical paleoweathering humid provenance Adigrat Sandstone 

摘      要：Mineralogical and geochemical studies have been undertaken on the Triassic to Lower Jurassic Adigrat Sandstone of the Blue Nile Basin of central Ethiopia to infer its source rock type,paleoweathering,and paleoclimatic *** Adigrat Sandstone occurs at the basal section of the Mesozoic sedimentary formation and unconformably overlays the Neoproterozoic–Paleozoic crystalline rocks,or locally,the Karroo sediments in the northern Blue Nile Basin.A mineralogical study reveals that quartz(Q),feldspars(F),and lithic fragments(L)are the framework grains of the *** the QFL diagram,the plot of the modal composition of the sandstone mainly falls within the feldspathic arenite and quartzose arenite *** geochemical data of the lower section of the sandstone mainly falls within the arkose and subarkose fields,whereas the upper section data falls within the quartzose and sublithic arenite *** and geochemical weathering indices indicate that the provenances of the Adigrat Sandstone were exposed to pronounced weathering intensity,where the lower part of the sandstone was controlled by arid to semi-arid conditions,whereas the upper section was linked to humid to semi-humid(tropical to subtropical)climatic *** and geochemical data also indicate that mafic to intermediate basement rocks were the primary source rocks of the *** the sediment was assumed to have been reworked by multi-cyclic sedimentary *** discriminant function diagram,the REE pattern,La/Th ***/Yb,and the Th–Hf–Co plot are consistent.A comparison of provenance studies for the Adigrat Sandstone in the Blue Nile Basin and the Mekele outlier of northern Ethiopia indicates that the sediment of the former is highly sorted,experienced higher weathering intensity,and compositionally derived from mafic to intermediate crystalline *** the other hand,the sediment of the latter is essentially a weathering product of felsic rocks.