The Tungho and Kangkou Limestones of the Coastal Range in eastern Taiwan have been deformed during the arc-continent collision since Pliocene. The stress and strain states of these deformed limestones are determined from the analysis of calcite twin lamellae. The present study shows that most limestones have suffered only a single phase of deformation under compressional stress. The derived maximum principal stress (σ1) is close to h orizontal and trends mainly in the range of 100° to 140° in azimuth. The directions of the σ2 and σ3 are either near horizontal or vertical and their magnitudes are nearly equal. Beside the compressional stress, other stress state responsible for normal faulting is also identified in few limestones around the Chinpu basin. This stress state is believed to have existed prior to the accretion of the Luzon volcanic arc. The strains measured in the deformed limestones are all less than 4%. The magnitude of strain decreases southward in the Kanghou Limestone but is rather random in the Tungho Limestone. The orientations of the principal strains are generally consistent with those of the principal stresses and reflect a nearly co-axial strain condition.
|Number of pages||14|
|Journal||Journal of the Geological Society of China|
|Publication status||Published - 1997 Oct 1|
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