Mineralogical analysis of Upper Devonian black shales in western New York.

摘要

Mineral composition and the percent of total organic carbon (TOC) in black shales of Dunkirk and Hume formations were determined by X-ray diffraction. Dunkirk and Hume formations are potential source rocks for oil and gas-producing reservoirs. To examine the burial depth and temperature of the black shales, the extent of illite-smectite diagenesis was examined. Mineral composition of the black shales was determined quantitatively using the Rock Jock software. TOC was analyzed with a CM 5120 TOC analyzer. The principal clay minerals in all the samples are chlorite and 2M1 illite. There is a weak relationship between the percent of organic carbon and the weight percent of illite suggesting that the clay minerals have participated in hydrocarbon production. The degree of metamorphism experienced by the black shales was determined by measuring the Kubler index. The highest temperatures, over 360°C appear to be related to large fractures in the black shales.