黑料网

Abstract

For the first time distinct clinoforms are reported from the Cenozoic shallow marine carbonate deposits of Oman (Paleocene to Eocene Jafnayn Formation, Sunub Basin, Greater Muscat). One outcrop of superb exposure displays well-developed transitions from a single topset unit to several hundred foreset beds. The former is a single massive to crudely-bedded, biostromatic red algae-bearing horizon. The latter emanate from the former at an angle of 15�?掳 and consist of carbonate debris. Due to foresetting of sediment, the foreset beds represent cross-beds in an overall aggradational sequence. Despite the great number of foreset beds, the paleoslope angle didn芒�?�?t change. The basal contact of the foreset beds is tangential (asymptotic), but the apices of the foreset beds are ill-defined. There are no bedding surfaces between the foreset beds and the red algae unit. Bedding surfaces that may have existed temporarily and must have been continuous from the red algae unit to the foreset beds are not preserved due to rapid deposition and rapid encrustation and binding by red algae. Progradation of the red algae unit over a paleoslope created several hundred foreset beds from the same red algae-bearing horizon, showing that the latter is time-transgressive. The red algae unit does not represent a classic 芒�?�?bed芒�?聺, considering its obvious diachroneity over short distance and its lack of a lower bedding surface. Local evidence for synsedimentary extensional faulting encourages the interpretation that such deformation caused the formation of the paleoslope. The microfacies suggests a shelf lagoon setting with open circulation. The occurrence of Ranikothalia sp. and Distychoplax biserialis demonstrates that the succession is of Paleocene to lowermost/Lower Eocene age.

Biography

Frank Mattern has received his PhD from Freie Universität Berlin, Germany. His specialty areas are Sedimentology, Basin Analysis and Structural Geology/ Tectonics. He has taught in Germany, Mexico, the USA and is presently an Associate Professor at Sultan Qaboos University in Muscat, Oman. His current research concerns the sedimentology of Paleozoic marine sandstones and Cenozoic limestones of Oman as well as structural/tectonic aspects of the region. In addition, he presently works on the facies interpretation and basin setting of Upper Triassic submarine fan deposits of the Langjiexue Group of southern Tibet as well as on the tectonics of the Songliao Basin, NE China.

Email: fmattern@zedat.fu-berlin.de