Geomorphological evidence for late Quaternary tectonic deformation of the Cape Region, coastal west central Australia

Abstract

A late Pleistocene (Marine Isotope Stage 5e) emergent marine sequence fringes the coastline of the Cape Region of coastal west central Australia and provides elevation and age control to characterize the locations and rates of crustal deformation. There is a systematic measurable change in relative paleo sea-level elevations across the Cape Region. High-precision leveling of modern and Pleistocene shoreline features indicates the minimum elevation range of MIS 5e shoreline features along the coast is 10.4 m. This compares with the 2.5 m elevation range for observed modern shoreline analogs. The lack of continuity of MIS 5e shoreline elevations along 300 km of coastline demonstrates continuing tectonic deformation along coastal anticlines in the Cape Region. Topographic expression of MIS 5e features indicates tectonic uplift consistent with late Neogene to Quaternary deformation on the Cape Cuvier and Cape Range anticlines. Post-MIS 5e tectonic uplift rates are up to 0.054 ± 0.035 mm/yr at fold axial locations. Estimated subsidence rates are − 0.013 ± 0.034 mm/yr on fold limbs. While the estimated vertical tectonic deformation is small and the rates are low, the geomorphological data also demonstrate tectonic activity, not stability.

Tertiary and quaternary marine terraces and planation surfaces of northern Oman: Interaction of flexural bulge migration associated with the Arabian-Eurasian collision and eustatic sea level changes

“…Studies were carried out using multispectral the remote sensing sensors such as Landsat, IRS, ASTER, SPOT, SRTM, InSAR for the identification and mapping of the terrace and planation surface features described above, following earlier pioneering work in these techniques (Li et al, 2015;Nasir, 2015, 2014;Van den Berg et al, 2015;Whitney and Hengesh, 2015;Zha et al, 2015;Haghipour and Burg, 2014;Li et al, 2012;Kusky et al, 2005;Kusky and Ramadan, 2002;Magilligan et al, 2002;Alsdorf and Smith, 1999;Williams et al, 1997;Richards, 1993). Haghipour and Burg (2014) used ASTER GDEM to analyze the coastal geomorphology and drainage system of the Makran accretionary wedge.…”

Flank margin cave development and tectonic uplift, Cape Range, Australia

“…One is that the sea level was stable for longer periods of time at the lower elevations and the increase in lens-stability time allowed a longer duration for flank margin caves to mature. This longer stability time would be consistent with a decreasing tectonic uplift rate, given that uplift is believed to have been completed by the Pliocene (Wyrwoll, et al, 1993), or if it has continued (Whitney and Hengesh, 2015) it has done so at a slow rate. The second explanation is that the high-level caves in the gorges are older, more degraded by surficial erosion, and have lost some of their original length and complexity; in their original state they would have been similar to the lower elevation paleo sea cliff caves.…”

“…5), indicating that surficial denudation by karst processes has lowered the land surface. Whitney and Hengesh (2015) indicate that tectonic movement is still active at Cape Range, with both uplift and subsidence occurring, with respective ranges of 0.049 6 0.030 mm yr À1 for uplift locations and À0.013 6 0.034 mm yr À1 for subsidence locations. As they assumed no karst denudation, which would place the dated corals at a higher elevation than measured today when first emergent, these estimates are therefore a minimum value.…”

“…The Cape Range anticline that forms North West Cape is 130 km long and 32 km wide, with a maximum elevation of 315 m (Whitney and Hengesh, 2015). The ridge is greatly dissected by stream valleys (Fig.…”

“…The Jurabi Member is dominated by coralgal boundstone considered late Pliocene based on the occasional shark's tooth (Wyroll, et al, 1993); the Tantabiddi Member contains lagoonal carbonate gravels and sands and is late Pleistocene (MIS 5e) based on a U/Th age of 132-127 ka (Collins et al, 2006). Whitney and Hengesh (2015) provide a compilation of Western Australia U/Th dates from late Pleistocene fossil reefs and provide an age range of 130-117 ka with a mean age of 123.5 6 6.5 ka. The Bundera Calcarenite underlies most of the coastal plain that fringes Cape Range.…”