Enigmatic seafloor structures in the Perth Basin (Houtman Sub-basin), offshore Western Australia: deep-water carbonate mounds or volcanic cones?

Gorter, John D.

doi:10.1080/08120090903246196

Cited by 2 publications

(3 citation statements)

References 11 publications

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“…This process may have occurred in south Western Australia given the fast motion of Australia since ~40 Ma (Whittaker et al, 2007), the steep gradient of lithospheric thickness between the Yilgarn Craton and the Perth Basin (Kennett and Salmon, 2012), and recent magmatic activity along the Western Australian margin (Gorter, 2009). Three--dimensional box models suggest that edge--driven convection at the trailing edge of a fast moving may result in vertical motions > 660 km downstream from the plate and ~80 Myr after acceleration of the plate (Farrington et al, 2010).…”

Section: Possible Secondary Mechanismsmentioning

confidence: 99%

Cenozoic uplift of south Western Australia as constrained by river profiles

et al. 2014

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The relative tectonic quiescence of the Australian continent during the Cenozoic makes it an excellent natural laboratory to study recent large--scale variations in surface topography, and processes that influence changes in its elevation.Embedded within this topography is a fluvial network that is sensitive to variations in horizontal and vertical motions. The notion that a river acts as a 'tape recorder' for vertical perturbations suggests that changes in spatial and temporal characteristics of surface uplift can be deduced through the analysis of longitudinal river profiles. We analyse 20 longitudinal river profiles around the Australian continent. Concave upward profiles in northeast Australia indicate an absence of recent surface uplift. In contrast, the major knickzones within longitudinal profiles of rivers in southwest Australia suggest recent surface uplift. Given the lack of recent large--scale tectonic activity in that region, this uplift requires an explanation. Applying an inverse algorithm to river profiles of south Western Australia reveals that this surface uplift started in the Eocene and culminated in the mid--late Neogene. The surface uplift rates deduced from this river profile analysis generally agree with independent geological observations including preserved shallow--marine sediment outcrops across the Eucla Basin and south Western Australia. We show that the interplay between global sea level and long--wavelength dynamic topography associated with south Western day geometry of longitudinal river profiles contains time--dependent information pertaining to the evolution of landscape vertical motions over larger spatial and temporal scales (i.e., ~1-100+ Myr, 10-1000 km; Roberts et al., 2012) in tectonically quiescent regions. In this method, time--dependent surface uplift rates are estimated by parameterizing the elevation of a river profile as a function of its length (Pritchard et al., 2009). Indeed, surface uplift results in rapid changes in gradient near the river mouth that, over time, migrate upstream as knickpoints (Whipple and Tucker, 1999). Depending on retreat rate, knickpoints may be preserved in present--day longitudinal river profiles, providing information on past uplift events.

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Section: Possible Secondary Mechanismsmentioning

confidence: 99%

Cenozoic uplift of south Western Australia as constrained by river profiles

et al. 2014

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“…Trace element abundances indicate a deep plume-like source and small degrees of partial melting. Gorter (2009) was unsure of the nature of the seamounts in the Houtman and Zeewyck Sub-basins suggesting either a magmatic or carbonate buildup origin. The lithology of recovered samples and their geochemistry documented within this study clearly indicates these are volcanic seamounts.…”

Section: Discussionmentioning

confidence: 95%

“…Gorter (2009) suggested that these mounds might be carbonate buildups. Samples collected during GA survey 2476 have shown that these features are basaltic edifices associated with relatively recent volcanic activity on the margin.…”

Section: Geological Setting Of the Offshore Perth Basinmentioning

confidence: 97%