Clay Cement Development in Faraghan Formation, Gahkum Mountain

Study of the Faraghan Formation sandstone illustrates the development of clay cements in them. Kaolinite is by far the most abundant clay cement in sandstones and smectite, illite and chlorite are the next frequent cements respectively. Dickite also occurs as the deep burial diagenetic product from kaolinite. Formation of kaolinite is attributed to shallow diagenetic environments mainly due to feldspar alteration. Formation of chlorite and illite is attributed to deep burial diagenetic environments due to transformation of bertierine and kaolinite precursors respectively. Smectite is suggested to form in either eogenetic or telogenetic environments. The maximum burial depth estimated for this formation, mainly based on the development of mesogenetic clays (i.e. chlorite, illite and dickite), is closely corresponding with the generation of gas.