本文選題：“斑晶”白云石 + 方沸石��； 參考：《古地理學(xué)報》2017年02期

【摘要】：準(zhǔn)噶爾盆地東部中二疊統(tǒng)平地泉組(相當(dāng)于蘆草溝組)發(fā)育一套陸內(nèi)裂谷背景下的湖泊相砂巖、泥巖、灰?guī)r、白云巖、凝灰?guī)r互層以及它們的過渡巖石,是區(qū)內(nèi)最主要的烴源巖和儲集層。近年來,在帳北斷褶帶、石樹溝凹陷和吉木薩爾凹陷中二疊統(tǒng)平地泉組暗色泥巖、泥晶白云巖中發(fā)現(xiàn)了一類特殊的沉積巖,該類巖石發(fā)育類似火山巖的斑狀結(jié)構(gòu)。"斑晶"主要為粗晶白云石、方解石、黃鐵礦及方沸石等,在巖心標(biāo)本上呈"樹枝狀"或"雪花狀"散布于基質(zhì)中;基質(zhì)則主要由泥晶白云石或泥質(zhì)沉積物構(gòu)成,富含有機(jī)質(zhì),發(fā)育水平層理及小型變形層理等。巖石學(xué)和礦物學(xué)分析表明,"斑晶"往往為粗晶方解石或白云石的集合體,也常見黃鐵礦、方沸石與碳酸鹽礦物共生,"斑晶"方解石發(fā)育環(huán)帶,而白云石未見明顯環(huán)帶。電子探針分析表明"斑晶"方解石具有低鎂、低鐵及鍶分布不均勻的特點(diǎn),而"斑晶"白云石(FeO含量介于7.272%~11.086%之間)與"基質(zhì)"泥晶白云石(FeO含量為1.027%)相比具有明顯富鐵的特點(diǎn)。流體包裹體分析表明"斑晶"方解石均一溫度平均為180.68℃,"斑晶"白云石均一溫度平均為320.95℃。這種特殊"斑狀"白云巖和"斑狀"泥質(zhì)巖很可能是湖底熱液噴流作用的結(jié)果。當(dāng)湖水沿深大斷裂下滲至地下深處,與圍巖發(fā)生物質(zhì)交換并被加熱后再沿斷裂返回地表噴涌而出,熱液流體攜帶的離子達(dá)到過飽和后就會析出方解石、白云石及黃鐵礦等集合體,隨熱液的噴涌作用上升并破碎散落于湖底細(xì)粒沉積物內(nèi)。"斑狀"白云巖的發(fā)現(xiàn)對新疆北部中二疊統(tǒng)熱水噴流沉積作用及該區(qū)油氣的成因研究具有重要的意義。
[Abstract]:A set of lacustrine sandstone, mudstone, limestone, dolomite, tuff interbeds and their transitional rocks are developed in the eastern part of Junggar Basin, the Middle Permian Pingdiquan formation (equivalent to the Lucaogou formation), and a set of lacustrine sandstone, mudstone, limestone, dolomite, tuff interbeds and their transitional rocks. Is the most important source rock and reservoir in the region. In recent years, a special type of sedimentary rocks have been found in the Middle-Permian Pingdiquan formation dark mudstone and mud-crystal dolomite in the Shanbei fault fold belt, Shishugou sag and Jimusar sag. The porphyry structure of this kind of rock is similar to that of volcanic rock. " The porphyry "is mainly composed of coarse dolomite, calcite, pyrite and alpinite, which are distributed in the matrix in the form of" dendritic "or" snowflake "on the core specimens, while the matrix is mainly composed of mudded dolomite or muddy sediments, which is rich in organic matter. Horizontal bedding and small deformation bedding. The petrological and mineralogical analysis shows that "porphyry" is often an aggregate of coarse-grained calcite or dolomite, pyrite is common, andalcite is symbiotic with carbonate minerals, porphyry calcite develops a ring zone, but dolomite does not. The electron probe analysis shows that the "porphyritic" calcite has the characteristics of low magnesium, low iron and uneven distribution of strontium, while the content of Feo in the "porphyry" dolomite is between 7.2722 and 11.086%) and that in the "matrix" mudstone dolomite is 1.027%). The analysis of fluid inclusions shows that the average homogenization temperature of "porphyry" calcite is 180.68 鈩，

本文編號：1823530