A STRUCTURAL AND PALEOMAGNETIC STUDY OF A SECTION THROUGH THE EASTERN SUBBETIC, SOUTHERN SPAIN

A well-exposed 2 km section through the Eastern Subbetic, immediately to the south of the Crevillente wrench fault zone can be divided into an upper thrust sheet of Triassic rocks, a middle thrust sheet of Cenomanian-Turonian basinal sediments, and a lower thrust sheet of Jurassic limestones unconformably overlain by Upper Cretaceous-Palaeocene sediments. Structural relationships suggest that the middle sheet overthrust the lower sheet; and both units were subsequently folded and imbricated. This sequence was then overthrust by the upper sheet, incorporating a footwall duplex of Cenomanian-Turonian sediments. These structures can be related to the complex deformation associated with a single overthrusting event. The dominant thrust transport direction is to the east, strongly oblique to the overall trend of the orogen. However, a palaeomagnetic study isolates stable components which indicate no cumulative vertical axis rotation of the thrust sheets. The section is cut by strike-slip faults whose displacements appear to be relatively minor. The Triassic rocks of the upper thrust sheet form a highly disrupted thrust sheet extending over much of the Subbetic, rather than being local to the Crevillente fault zone. This section through the Subbetic can be interpreted as the result of a major east-directed thrust of basinal sediments of the Median Subbetic over marginal shelf facies of the Internal Subbetic, strongly oblique to the general ESE trend of the orogen. The shortened sequence is cut by a later set of strike slip faults which are probably related to movement on the Crevillente fault.