兰州大学学报（自然科学版）
蘭州大學學報（自然科學版）
란주대학학보（자연과학판）
JOURNAL OF LANZHOU UNIVERSITY（NATURAL SCIENCES）
2012年
6期
8-14
,共7页
白云岩%碳、氧同位素%乌尔禾?风城地区%准噶尔盆地
白雲巖%碳、氧同位素%烏爾禾?風城地區%準噶爾盆地
백운암%탄、양동위소%오이화?풍성지구%준갈이분지
dolomite%carbon and oxygen isotope%Wuerhe-Fengcheng area%Junggar basin
以白云岩的地球化学方法为主,对准噶尔盆地西北缘乌尔禾?风城地区二叠系风城组广泛发育的白云岩化岩类进行详细的研究.通过对乌尔禾?风城地区二叠系风城组白云岩化岩类的元素分析、碳氧同位素和古盐度、古温度的研究,得出研究区白云岩类以白云质泥岩、泥质白云岩和凝灰质白云岩三种形态存在.白云质岩类富含陆源碎屑(泥质)或凝灰岩组分;白云质岩类中c(Mg)/c(Ca)分布范围较宽,主要分布于0.636～4.785,平均值为1.532,大部分分布于1～2,说明研究区有丰富的Mg2+供应;白云质岩类中w(Sr)较高,主要为95.9×10?6～783.6×10?6,平均值为464.95×10?6, w(V)/w(Ni)为0.8～4.8,主要为2～3;研究区二叠系白云质岩类的δ18O和δ13C值分布范围较大,δ13C为?1‰～5.2‰,平均值为3.1‰,δ18O为?14.8‰～3.2‰,平均值为?2.8‰.由地球化学元素分析结合古温度和古盐度分析认为研究区风城组白云岩形成于一盐度较高、温度偏低的环境中,火山喷发的热液活动对白云岩的形成也有一定的影响.白云质岩类形成大部分发生为成岩早期,少部分白云岩化发生为成岩中晚期的埋藏时期,总的来说白云质岩类形成于早成岩阶段的陆相咸水湖泊中.
以白雲巖的地毬化學方法為主,對準噶爾盆地西北緣烏爾禾?風城地區二疊繫風城組廣汎髮育的白雲巖化巖類進行詳細的研究.通過對烏爾禾?風城地區二疊繫風城組白雲巖化巖類的元素分析、碳氧同位素和古鹽度、古溫度的研究,得齣研究區白雲巖類以白雲質泥巖、泥質白雲巖和凝灰質白雲巖三種形態存在.白雲質巖類富含陸源碎屑(泥質)或凝灰巖組分;白雲質巖類中c(Mg)/c(Ca)分佈範圍較寬,主要分佈于0.636～4.785,平均值為1.532,大部分分佈于1～2,說明研究區有豐富的Mg2+供應;白雲質巖類中w(Sr)較高,主要為95.9×10?6～783.6×10?6,平均值為464.95×10?6, w(V)/w(Ni)為0.8～4.8,主要為2～3;研究區二疊繫白雲質巖類的δ18O和δ13C值分佈範圍較大,δ13C為?1‰～5.2‰,平均值為3.1‰,δ18O為?14.8‰～3.2‰,平均值為?2.8‰.由地毬化學元素分析結閤古溫度和古鹽度分析認為研究區風城組白雲巖形成于一鹽度較高、溫度偏低的環境中,火山噴髮的熱液活動對白雲巖的形成也有一定的影響.白雲質巖類形成大部分髮生為成巖早期,少部分白雲巖化髮生為成巖中晚期的埋藏時期,總的來說白雲質巖類形成于早成巖階段的陸相鹹水湖泊中.
이백운암적지구화학방법위주,대준갈이분지서북연오이화?풍성지구이첩계풍성조엄범발육적백운암화암류진행상세적연구.통과대오이화?풍성지구이첩계풍성조백운암화암류적원소분석、탄양동위소화고염도、고온도적연구,득출연구구백운암류이백운질니암、니질백운암화응회질백운암삼충형태존재.백운질암류부함륙원쇄설(니질)혹응회암조분;백운질암류중c(Mg)/c(Ca)분포범위교관,주요분포우0.636～4.785,평균치위1.532,대부분분포우1～2,설명연구구유봉부적Mg2+공응;백운질암류중w(Sr)교고,주요위95.9×10?6～783.6×10?6,평균치위464.95×10?6, w(V)/w(Ni)위0.8～4.8,주요위2～3;연구구이첩계백운질암류적δ18O화δ13C치분포범위교대,δ13C위?1‰～5.2‰,평균치위3.1‰,δ18O위?14.8‰～3.2‰,평균치위?2.8‰.유지구화학원소분석결합고온도화고염도분석인위연구구풍성조백운암형성우일염도교고、온도편저적배경중,화산분발적열액활동대백운암적형성야유일정적영향.백운질암류형성대부분발생위성암조기,소부분백운암화발생위성암중만기적매장시기,총적래설백운질암류형성우조성암계단적륙상함수호박중.
By means of dolomite geochemical methods, an elaborate study was carried out on dolomitized rocks which are of widely distributed permian Fengcheng formation at Wuerhe-Fengcheng area in the northwest margin of the Junggar basin. According to element analysis, carbon and oxygen isotopic analysis, and paleogeotherm and paleosalinity of the permian Fengcheng formation dolomitized rocks, we have drawn the conclusions that dolomite rich in terrigenous clastic (muddy) or tuff component; c(Mg)/c(Ca) is between 0.636 and 4.785, with the average being 1.532 and most of them ranging between 1 and 2;w(Sr) is distributed 95.9×10?6～783.6×10?6, with the average being 464.95×10?6;w(Vi)/w(Ni) is between 0.8 and 4.8, with the most being between 2 and 3. However, δ18O and δ13C are very scattered, the main δ13C is between ?1‰ and 5.2‰, with the average being 3.1‰, and the main δ18O ranges from ?14.8‰ to 3.2‰, the average being ?2.8‰. Based on the geochemical element analysis combined with the temperature and paleosalinity analysis, it was concluded that the Fengcheng formation dolomite formed on a higher salinity and low temperature environmentl volcano hydrothermal activities also have had a certain influence on the dolomite formation; dolomitic rock formation occurred mostly in the low diagenetic stage; little occurred in the late diagenesis burial period and overall dolomitic rocks formed in the early diagenetic stage of continental saline lakes.
