A review of the geotectonic theories and tectonic maps of Indonesia

Abstract

A generation of fine Dutch tectonic geologists had already recognized decades ago that the Indonesian Archipelago possesses a dual character, namely as the place of intersection of two of the largest mountain systems and as an intracontinental zone between the Asiatic and Australian continents. They also realized that the Indonesian island arcs represent a mountain belt in statu nascendi, exhibiting a systematic relationship of active tectonic and magmatic features to the deep submarine trenches. The various structural schemes and maps of Indonesia developed since the turn of this century and mainly intended to express and sustain the different tectonic theories, are critically reviewed in these pages. It is concluded that the new concept of plate tectonics featuring the Indonesian island arcs as the place of interaction of two or more crustal plates could best be used as a basis to explain various physiographical, geological and geophysical phenomena such as the deep submarine trenches, the loop-shaped arc, zonal arrangement of the structural belts, large transcurrent faults, lateral variation of andesitic magma type across the arc and shallow, intermediate and deep earthquakes which exhibit a tendency to have their epicenters farther into the Asiatic continent. Two apparently controversial theories, those of continental accretion and of continental drift, respectively applicable to the western and eastern part of Indonesia, are also compatible with, and found to be complementary in the light of, the plate-tectonic concept. A widely accepted cartographic depiction of the tectonic features of Indonesia, however, will not be easily achieved due to the complexity of the structural relationship and the scarcity of geological literature.