Post-rift seaward downwarping at passive margins: new insights from southern Oman using stratigraphy to constrain apatite fission-track and (U-Th)/He dating - Sorbonne Université Access content directly
Journal Articles Geology Year : 2007

Post-rift seaward downwarping at passive margins: new insights from southern Oman using stratigraphy to constrain apatite fission-track and (U-Th)/He dating

Abstract

The plateau edge of southern Oman is used as a natural laboratory to independently test apatite fi ssion-track analysis, (U-Th)/He dating, and stratigraphy as methods for quantifying post-rift erosion depths and lithospheric response at passive margins. A mappable unconformity between the Proterozoic basement and the low-conductivity, pre-rift sediment cover links residual buttes preserved at the coast to the escarpment, and therefore imposes tight limitations on parameter choices for modeling the Cenozoic topographic evolution. A mean geothermal gradient of ~33 °C km-1 ensures the best fi t between the thermochronologic data and the stratigraphically defi ned coast-to-scarp maximum denudation depth of ~1.75 km. With a lithospheric elastic thickness of 7 km, the resulting fl exural response generates a retreat and uplift of the escarpment associated with a seaward downwarp of the unconformity, made possible because denudation minima are inboard of the escarpment and sediment loading occurs offshore. This closed experiment confi rms the value of low-temperature thermochronology as a tool for quantifying long-term erosion, but also highlights the benefi ts of including independent stratigraphic information in terms of obtaining more plausible solutions. This study suggests that post-rift downwarping of eroded rift shoulders can occur, and may have not been commonly detected because low-temperature thermochronology data sets lack both suitable geologic data and intrinsic sensitivity.
Fichier principal
Vignette du fichier
Gunnell_et_HAL_Geology_2007.pdf (472.89 Ko) Télécharger le fichier
Origin : Files produced by the author(s)
Loading...

Dates and versions

hal-00582703 , version 1 (06-04-2011)

Identifiers

Cite

Yanni Gunnell, Andy Carter, Carole Petit, Marc Fournier. Post-rift seaward downwarping at passive margins: new insights from southern Oman using stratigraphy to constrain apatite fission-track and (U-Th)/He dating. Geology, 2007, 35, pp.647-650. ⟨10.1130/G23639A.1⟩. ⟨hal-00582703⟩
340 View
1086 Download

Altmetric

Share

Gmail Facebook X LinkedIn More