Charakterystyka mikrolitofacji oraz warunków paleotemperaturowych skał ediakaru w otworze wiertniczym Bibiela PIG-1
Abstract
The characteristics of microlithofacies and palaeotemperature conditions of Ediacaran rocks in the Bibiela PIG-1 borehole.
A b s t r a c t. The paper presents results of new petrographic and mineralogical analyses of Ediacaran clastic rocks in the Bibiela PIG-1 borehole drilled in 2016. Three types of microlithofacies have been distinguished. The basic types of rocks are siltstones and claystones containing thin layers of mudstones. Breccia is common, while sandstones form thin packages. The Ediacaran rocks are cut by numerous veins that intersect each other. They are filled with carbonates, quartz, chlorites and kaolinite. Ankerite, Fe-dolomite, dolomite, Mg-siderite (sideroplesite, pistomesite, metisite), Mn-siderite (manganosiderite) and Fe/Mn-calcite were identified among the carbonate minerals. Vitrinite reflectance index Ro (1.68%), Kübler index KI (0.72 to 1.10 Δo2θ CuK2) and smectite content (10–25%) in the mixed-layer illite/smectite indicate that the Ediacaran rocks in the Bibiela PIG-1 borehole have been altered under the conditions of late diagenesis at the maximum temperature estimated at approx. 160oC.
A b s t r a c t. The paper presents results of new petrographic and mineralogical analyses of Ediacaran clastic rocks in the Bibiela PIG-1 borehole drilled in 2016. Three types of microlithofacies have been distinguished. The basic types of rocks are siltstones and claystones containing thin layers of mudstones. Breccia is common, while sandstones form thin packages. The Ediacaran rocks are cut by numerous veins that intersect each other. They are filled with carbonates, quartz, chlorites and kaolinite. Ankerite, Fe-dolomite, dolomite, Mg-siderite (sideroplesite, pistomesite, metisite), Mn-siderite (manganosiderite) and Fe/Mn-calcite were identified among the carbonate minerals. Vitrinite reflectance index Ro (1.68%), Kübler index KI (0.72 to 1.10 Δo2θ CuK2) and smectite content (10–25%) in the mixed-layer illite/smectite indicate that the Ediacaran rocks in the Bibiela PIG-1 borehole have been altered under the conditions of late diagenesis at the maximum temperature estimated at approx. 160oC.