Geochemistry of the Aptian bituminous limestones in Gümuü?hane area,Eastern Black Sea region:new insight into paleogeography and paleoclimate conditions

作     者：Merve Ozyurt Merve Özyurt

作者机构：Geological Engineering DepartmentKaradeniz Technical UniversityOrtahisarTrabzon TR-61080Turkey 

出 版 物：《Acta Geochimica》 (地球化学学报（英文）)

年 卷 期：2023年第42卷第6期

页      面：971-987页

核心收录：

学科分类：070902[理学-地球化学] 070903[理学-古生物学与地层学(含：古人类学)] 0709[理学-地质学] 07[理学] 

基　　金：University of Windsor Karadeniz Teknik Üniversitesi, KTU 

主　　题：Aptian Paleoclimate Sedimentary conditions Geochemistry REE C and O isotopes Limestone Eastern Black Sea 

摘      要：Aptian is characterized by widespread deposition of organic-rich *** Aptian bitumen limestone horizon,which is thin decimetre-thick sequences,locally crops out in the Kircaova area,Eastern Black Sea Region(Eastern Pontides).They are well correlated with Aptian bitumen limestone in the other Tethys *** are proposed as episodes of increased organic ***,background factors controlling organic matter enrichment are poorly *** this study,we present new inorganic geochemistry,including trace elements,rare earth elements(REE),redox-sensitive elements(RSE),stable-isotopes(δ~(18)O andδ~(13)C),and total organic carbon(TOC).We integrated new geochemical data with existing stratigraphy,paleontology,and organic chemistry data to provide new insight into the depositional environment and paleoclimate conditions during *** lacustrine bitumen limestone(LBL)samples have variedδ~(13)C(ave.-1.45‰)andδ~(18)O(ave.-4.50‰).They possess distinct REE patterns,with an average of REE(ave.14.45 ppm)and Y/Ho(ave.35)*** addition,they have variable Nd/YbN(0.28-0.81;ave.0.56)and Ce/Ce*(0.68-0.97;ave.0.86),and relatively high Eu^(*)/Eu(1.23-1.53;ave.1.35).They display seawater signatures with reduced oxygen *** enrichment in RSE(Mo,Cu,Ni,and Zn)and the low Mo/TOC(0.70-3.69;ave.2.41)support a certain degree of water *** high Sr/Ba,Sr/Cu,Ga/Rb,and K/Al records of the LBL facies suggest hot house climatic *** sedimentary environment was probably an isolated basin that is transformed from the marine *** addition to depositional conditions,the regional parameters such as the climate,increased run-off period,nutrient levels,alkalinity level,and dominant carbonate producers favored the enrichment in organic matter of LBL ***,extreme greenhouse palaeoclimate conditions have an important role in organic matter enrichment in the isolated *** results are conformable with the published data from marine,semi-restrict