EVIDENCE OF MULTIPHASE DEFORMATION IN THE RAJANG-CROCKER RANGE (NORTHERN BORNEO) FROM LANDSAT IMAGERY INTERPRETATION - GEODYNAMIC IMPLICATIONS

Landsat imagery, structural analysis and nannoplankton dating of the Rajang-Crocker Belt in northern Borneo defines the geometry, style and timing of the development of various tectonostratigraphic units. These data are integrated with a review of the formations of the area in order to to emphasize the palaeogeographic environments of the units. In Sarawak, the trends are essentially E-W, with a first event being characterized by strong deformation and schistosity which affects Upper Cretaceous-Lower Eocene terrigeneous units prior to the deposition of the Middle-Upper Eocene. A second event is marked by the northward thrusting of Eocene rocks over the Oligocene, prior to the deposition of the Middle Miocene succession. In the Crocker Belt of Sabah, two oblique generations of structures can be observed. These deformations occurred prior to the deposition of the Upper-Middle Miocene. Tight or even reverse folds with N-S trending axes are deformed by large folds with associated thrusts. The axes of these last structures trend N-S in the Brunei area, N60E in Northern Sabah, and bend towards N130E in the Sandakan area. This complex pattern has been affected by late N60E-trending normal faults in Central Sabah. © 1990.