QUATERNARY UPLIFT OF CORAL TERRACES FROM ACTIVE FOLDING AND THRUSTING ALONG THE NORTHERN COAST OF TIMOR-LESTE

Emergent coral terraces along the northern coast of Timor-Leste reveal differential vertical strain along the strike of the active Banda arc-continent collision complex. The number of distinct coral terraces in surveyed profiles increases from 2 to 25 along a coastal distance of 150 km from central to eastern Timor-Leste. Terraces are warped over length-scales of < 25 km, which implies a crustal vs. lithospheric level deformational process. Field surveys of emergent coral terraces at 8 separate coastal locations, in conjunction with remote sensing studies of the coastal region, indicate tilt to the south and west, which is corroborated by stream asymmetry studies. Comparison of terrace altitudes with sea level curves, in conjunction with preliminary U-series ages for the lowest terrace at several transects, predicts vertical displacement rates that increase eastward from < 0.3 to 1.0-1.5 mm/year. We associate active uplift with northward movement along retro-wedge thrust faults that are well documented in seismic reflection profiles adjacent to the north coast of Timor-Leste.