Fig. 4
From: Using Mg isotopes to constrain the formation temperature of dolomite
The petrological characteristics of dolostone from the Ediacaran to Ordovician periods in the Tarim Basin. (A) Hand specimens of micro-fine crystalline dolostone (D1), grayish black, XX-15; (B) Microphotograph of D1 showing the dolomite crystal diameter is less than 50 μm, XX-15, imaged under plane-polarized light; (C) Foamy-layered or algal-clotted sedimentary fabric of D1, XX-27, imaged under plane-polarized light; (D) Hand specimen of fine-medium crystalline dolostone (D2), dark gray, XX-68; (E) Microphotograph of D2, XX-41, imaged under plane-polarized light; (F) Microphotograph of D2 has obvious residual granule structure, XX-68, imaged under plane-polarized light; (G) Hand specimen of medium-coarse crystalline dolostone (D3), light gray, GC17-23; (H) Microphotograph of D3, LS2-7, imaged under plane-polarized light; (I) Dolomite with “foggy core and bright edge” and undulatory extinction, GC17-1, imaged under crossed polars.
