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Denudational isostatic rebound of intraplate highlands: The lachlan river valley, Australia
Author(s) -
Bishop Paul,
Brown Roderick
Publication year - 1992
Publication title -
earth surface processes and landforms
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.294
H-Index - 127
eISSN - 1096-9837
pISSN - 0197-9337
DOI - 10.1002/esp.3290170405
Subject(s) - denudation , geology , lithosphere , post glacial rebound , geomorphology , erosion , bedrock , geochemistry , earth science , tectonics , paleontology , ice sheet
A range of evidence from the Lachlan valley in the southeast Australian highlands is consistent with Neogene isostatic rebound in response to denudational unloading. This evidence is found along the inland edge of the highlands in the transition zone between the highlands proper and the Lachlan's inland alluviated valley and the intracratonic Murray Basin. The amounts and rates of uplift indicated by offsets of suballuvium bedrock profiles and the long profiles of Tertiary valley‐filling basalts are consistent with modelling of denudational rebound using known rates of highland denudation and basinal sedimentation, and reasonable crustal properties. The modelling shows that weak to moderately strong strong lithosphere (effective elastic thickness, T e = 1‐25 km) and strong lithosphere ( T e = 100 km) are all consistent with the observed amounts of rebound. Strong lithosphere must be broken, however, to be consistent with the field data. Even in the Australian setting, which is characterized by very low rates of denudation, isostatic rebound in response to denudational unloading must be a significant factor in maintaining highland elevation and must be incorporated in models of long‐term landscape evolution. It would be expected that denudational isostatic rebound would be an even more significant component of long‐term landscape evolution in areas of higher denudation rates.