Evolution of deep‐water rifted margins: Testing depth‐dependent extensional models

Crosby, Alistair; White, Nicky; Edwards, G. R.; Thompson, Mark; Corfield, Richard; Mackay, L. M.

doi:10.1029/2010tc002687

Cited by 40 publications

(26 citation statements)

References 135 publications

(246 reference statements)

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“…However, by locating the region of plume impact from maximum denudation and increased magmatism, these issues can be circumvented. Moreover, a recent assessment of paleo-water depths at deep-water margins (Crosby et al, 2011) indicated that uncertainties can be greatly reduced by sticking to a few rules: (1) using negligible bathymetry at the start of rifting, (2) using geometry of seismic reflectors, such as clinoforms, indicative of potential changes in paleobathymetry, and (3) relating the predicted time-depth cooling of nearby oceanic crust to deep-water margins.…”

Section: Discussionmentioning

confidence: 99%

Delineating the Exmouth mantle plume (NW Australia) from denudation and magmatic addition estimates

Rohrman¹

2015

Lithosphere

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Volcanic margins are a class of large igneous provinces (LIPs) characterized by rifting-derived basaltic magmatism. This is commonly attributed to extension-related lithospheric thinning, generating decompression melting. Another mechanism influencing magmatism on volcanic margins is mantle plume-induced lithospheric thinning. Unfortunately, it is difficult to differentiate between these mechanisms because they seem to take place almost contemporaneously. Whereas rifted volcanic margins produce linear denudation and magmatic addition patterns, mantle plumes or active upwellings would generate more subcircular domal patterns. Here, I use magmatic addition and denudation patterns to discriminate between these scenarios in a data set from the volcanic margin offshore NW Australia. Seismic and well data results suggest the presence of a domal component that is used to delineate the Late Jurassic Exmouth mantle plume. This upwelling was centered on a highly extended and subsided continental fragment bounded by the present-day subsea Sonne and Sonja Ridges and includes the Cuvier margin and Cape Range fracture zone. The region is characterized by ~2.6 km of denudation and ~500 m of tectonic uplift, with erosion products acting as source material for the Early Cretaceous Lower Barrow delta. Denudation analysis indicates that only ~40% of the seismically detected magmatic underplate is melt related, with the effective underplate ~4 km thick near the locus of uplift and decreasing in the outer regions. Tectonic subsidence analysis, seismic stratigraphy, and plate reconstruction suggest that the plume-induced domal uplift preceded magmatism and breakup. Plume activity was followed by a westward-propagating hotspot track, possibly terminating in Greater India (present Tibet).

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Section: Discussionmentioning

confidence: 99%

Delineating the Exmouth mantle plume (NW Australia) from denudation and magmatic addition estimates

Rohrman¹

2015

Lithosphere

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“…There, the thickness of the lithosphere of the African margin is 100 km at the trench, and 65‐km beneath the Aegean volcanic arc, suggesting that the African lithosphere is thinned as it is being subducted and recycled in the upper mantle. It worthwhile to note that, in Apulia, both for a “Type I” rifted margin, where continental lithospheric mantle is removed, and “Type II” rifted margin (due to the proximity of the ocean‐continent boundary), the mean value of the thickness of the lithosphere should be similar to the lithospheric thickness of the adjoined oceanic plate [ Crosby et al , 2011]. Such an interpretation does not agree with the classical thermal model for the thickening of the oceanic lithosphere where the lithosphere of a 200 My old oceanic plate would be more than 100 km thick, supporting the idea of a different process for the evolution of the LAB in this region.…”

Section: Discussionmentioning

confidence: 99%

Erosion of the continental lithosphere at the cusps of the Calabrian arc: Evidence fromSreceiver functions analysis

Miller

Agostinetti

2011

Geophys. Res. Lett.

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Mediterranean tectonics has been characterized by an irregular, complex temporal evolution with episodic rollback and retreat of the subducted plate followed by period of slow trench‐migration. To provide insight into the geodynamics of the Calabrian arc, we image the characteristics and lithospheric structure of the convergent, Apulian and Hyblean forelands at the cusps of the arc. Specifically we investigate the crustal and lithospheric thicknesses using teleseismic S‐to‐p converted phases, applied to the Adria‐Africa plate margin for the first time. We find that the Moho in the Apulian foreland is nearly flat at ∼30 km depth, consistent with previousPreceiver functions results, and that the Hyblean crustal thickness is more complex, which can be understood in terms of the nature of the individual pieces of carbonate platform and pelagic sediments that make up the Hyblean platform. The lithospheric thicknesses range between 70–120 km beneath Apulia and 70–90 km beneath Sicily. The lithosphere of the forelands at each end of the Calabrian arc are continental in nature, buoyant compared to the subducting oceanic lithosphere and have previously been interpreted as mostly undeformed carbonate platforms. Our receiver function images also show evidence of lithospheric erosion and thinning close to Mt. Etna and Mt. Vulture, two volcanoes which have been associated with asthenospheric upwelling and mantle flow around of the sides the slab. We suggest that as the continental lithosphere resists being subducted it is being thermo‐mechanically modified by toroidal flow around the edges of the subducting oceanic lithosphere of the Calabrian arc.

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“…Published maps of residual topography often use global grids of sedimentary and crustal thicknesses to estimate water‐loaded subsidence [ Colin and Fleitout , ; Panasyuk and Hager , ; Kaban et al ., ; Steinberge , ; Crosby and McKenzie , ]. Unfortunately, there are significant errors in existing digital grids, especially on the oldest, highly sedimented oceanic crust [ Crosby et al ., ]. Winterbourne et al .…”

Section: Residual Topography Of Oceanic Lithospherementioning

confidence: 99%

Spatial and temporal patterns of Cenozoic dynamic topography around Australia

Czarnota

Hoggard²,

White³

et al. 2013

Geochem Geophys Geosyst

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[1] Despite its importance, the spatial and temporal pattern of dynamic topography generated by mantle convective circulation is poorly known. We present accurate estimates of dynamic topography from oceanic basins and continental margins surrounding Australia. Our starting point is measurement of residual depth anomalies on the oldest oceanic floor adjacent to the continental shelf. These anomalies were determined from a combined dataset of~200 seismic reflection and wide-angle images of well-sedimented oceanic crust. They have amplitudes of between À1 km and +0.5 km, and their spatial variation is broadly consistent with long-wavelength free-air gravity and shallow seismic tomographic anomalies. Along the Northwest Shelf, a regional depth anomaly of À300 to À700 m intersects the adjacent continental shelf. The temporal evolution of this anomaly was determined by analyzing the stratigraphic architecture of an extensive carbonate platform, which fringes the shelf and records a dramatic switch from progradation to aggradation during Neogene times. Three-dimensional seismic mapping calibrated by boreholes was used to calculate water-loaded subsidence histories at rollover points of clinoforms along the shelf. At 9 AE 3 Ma, the rate of subsidence increases from 5 to up 75 m Myr À1 , generating a subsidence anomaly of À300 to À700 m. The amplitude of this anomaly varies along the shelf and cannot be generated by glacio-eustatic sea-level variation. Instead, we propose that a regional subsidence episode, which affects both the proximal shelf and the distal oceanic basin, was generated by convective drawdown. By combining our results with other published estimates of uplift and subsidence, a map of Australia, which shows the spatial and temporal pattern of dynamic topography is presented. Most, but not all, of Australia's epeirogeny can be attributed to rapid northward motion of the Australian plate over a pre-existing pattern of convective circulation.

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Evolution of deep‐water rifted margins: Testing depth‐dependent extensional models

Cited by 40 publications

References 135 publications

Delineating the Exmouth mantle plume (NW Australia) from denudation and magmatic addition estimates

Delineating the Exmouth mantle plume (NW Australia) from denudation and magmatic addition estimates

Erosion of the continental lithosphere at the cusps of the Calabrian arc: Evidence fromSreceiver functions analysis

Spatial and temporal patterns of Cenozoic dynamic topography around Australia

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