發(fā)布時間：2019-01-03 09:03

【摘要】：鄂爾多斯盆地馬家溝組五段白云巖,按照晶�？煞譃閮煞N類型:晶粒較細的M型微晶白云巖和晶粒相對較粗的F型粉細晶白云巖。這兩類白云巖都具有較高的Fe含量,但Fe并不是均一分布的。在M型微晶白云巖中,基質(zhì)白云石的鐵含量為583×10~(-6)~3 811×10~(-6),富鐵白云石主要以膏溶鑄�？椎目紫冻涮钗锏男问酱嬖�,粗晶白云石充填物鐵含量29 112×10~(-6)~47 148×10~(-6),均勻分布于晶體之中;而粉晶白云石充填物,鐵含量最可達81 752×10~(-6),僅富集于白云石的邊緣。在F型粉-細晶白云巖中,其基質(zhì)白云石的鐵含量為233×10~(-6)~2 007×10~(-6);裂縫和孔隙內(nèi)充填的白云石的鐵含量較高,可達9 178×10~(-6),均勻分布。鐵的富集可能與孔隙的發(fā)育有一定聯(lián)系�？紫对桨l(fā)育,容易富集鐵。M型微晶白云石的δ~(13)C(V-PDB)值為-3.5‰~1.4‰,δ~(18)O(V-PDB)值為-6.5‰~-8.0‰;孔隙充填物粉晶白云石δ~(13)C(V-PDB)值為-0.7‰~-2.7‰,δ~(18)O(V-PDB)值在-9.8‰~-11.5‰;粗晶白云石的δ~(13)C(V-PDB)值范圍為-1.7‰~-2.9‰,δ~(18)O(V-PDB)值范圍為-9.9‰~-11.3‰,可能受到過較高溫度流體的影響。F型粉細晶白云巖的δ~(13)C(V-PDB)值為-0.4‰~-0.8‰,δ~(18)O(V-PDB)值為-5.3‰~-6.6‰,與海水較為接近。兩類白云巖的Fe可能來源于上覆的鐵質(zhì)粘土巖。白云巖形成后,后經(jīng)歷了漫長的風(fēng)化暴露剝蝕,形成了大量的儲集空間,并殘存形成了上覆鐵質(zhì)粘土巖。當再次進入埋藏期后,鐵質(zhì)粘土巖中富鐵的流體在重力的作用下,向下部的地層運移,且到一定深度時,氧化態(tài)Fe3+轉(zhuǎn)化為還原態(tài)的Fe2+,且已具有相對較高的地溫,使得Fe2+更容易進入白云石晶格,形成了富鐵的白云巖層系。
[Abstract]:There are two types of dolomite in the fifth member of Majiagou formation, Ordos Basin: M type fine dolomite with fine grain size and F type fine grain dolomite with relatively coarse grain. Both types of dolomite have high Fe content, but Fe is not uniformly distributed. In M-type microcrystalline dolomite, the iron content of matrix dolomite is 583 脳 10 ~ (-6) ~ 3 811 脳 10 ~ (-6). The iron content of coarse dolomite filling is 29 112 脳 10 ~ (-6) ~ 47 148 脳 10 ~ (-6), which distributes uniformly in the crystal. However, the iron content of powdered dolomite filling is 81,752 脳 10 ~ (-6), which is only concentrated on the edge of dolomite. The iron content of dolomite matrix is 233 脳 10 ~ (-6) ~ 2 007 脳 10 ~ (-6) in F-type powder-fine-grained dolomite, and the iron content of dolomite filled in fractures and pores is high, up to 9 178 脳 10 ~ (-6). The enrichment of iron may be related to the development of pores. The microcrystalline dolomite of M type has 未 ~ (13) C (V-PDB) values of -3.5 鈥，

本文編號：2399169