Spatial and temporal patterns of Cenozoic dynamic topography around Australia

被引:71
作者
Czarnota, K. [1 ,2 ]
Hoggard, M. J. [1 ]
White, N. [1 ]
Winterbourne, J. [3 ]
机构
[1] Bullard Labs, Cambridge CB3 0EZ, England
[2] Geosci Australia, Canberra, ACT 2601, Australia
[3] BP Explorat Operating Co Ltd, Sunbury On Thames TW16 7BP, Middx, England
关键词
Dynamic topography; sea level; Australia; Neogene; WESTERN-AUSTRALIA; CRUSTAL THICKNESS; OCEAN-FLOOR; HEAT-FLOW; DEPTH; EVOLUTION; MANTLE; BASIN; CONSTRAINTS; SUBSIDENCE;
D O I
10.1029/2012GC004392
中图分类号
P3 [地球物理学]; P59 [地球化学];
学科分类号
0708 ; 070902 ;
摘要
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 similar to 200 seismic reflection and wide-angle images of well-sedimented oceanic crust. They have amplitudes of between -1 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 -300 to -700 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 +/- 3 Ma, the rate of subsidence increases from 5 to up 75 m Myr(-1), generating a subsidence anomaly of -300 to -700 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.
引用
收藏
页码:634 / 658
页数:25
相关论文
共 93 条
[11]   GLOBAL COUPLING OF EARTH SURFACE-TOPOGRAPHY WITH HOTSPOTS, GEOID AND MANTLE HETEROGENEITIES [J].
CAZENAVE, A ;
SOURIAU, A ;
DOMINH, K .
NATURE, 1989, 340 (6228) :54-57
[12]  
Christensen N.I., 1982, Handbook of Physical Properties of Rocks, V2, P2
[13]   TOPOGRAPHY OF THE OCEAN-FLOOR - THERMAL EVOLUTION OF THE LITHOSPHERE AND INTERACTION OF DEEP MANTLE HETEROGENEITIES WITH THE LITHOSPHERE [J].
COLIN, P ;
FLEITOUT, L .
GEOPHYSICAL RESEARCH LETTERS, 1990, 17 (11) :1961-1964
[14]  
COLLINS LB, 1984, AUST J EARTH SCI, V31, P287, DOI 10.1080/14400958408527931
[15]   QUATERNARY DEVELOPMENT OF RESILIENT REEFS ON THE SUBSIDING KIMBERLEY CONTINENTAL MARGIN, NORTHWEST AUSTRALIA [J].
Collins, Lindsay B. ;
Testa, Viviane .
BRAZILIAN JOURNAL OF OCEANOGRAPHY, 2010, 58 :67-77
[16]   The relationship between depth, age and gravity in the oceans [J].
Crosby, A. G. ;
McKenzie, D. ;
Sclater, J. G. .
GEOPHYSICAL JOURNAL INTERNATIONAL, 2006, 166 (02) :553-573
[17]   Evolution of deep-water rifted margins: Testing depth-dependent extensional models [J].
Crosby, A. G. ;
White, N. J. ;
Edwards, G. R. H. ;
Thompson, M. ;
Corfield, R. ;
Mackay, L. .
TECTONICS, 2011, 30
[18]   An analysis of young ocean depth, gravity and global residual topography [J].
Crosby, A. G. ;
McKenzie, D. .
GEOPHYSICAL JOURNAL INTERNATIONAL, 2009, 178 (03) :1198-1219
[19]   THE CORRECTION FOR SEDIMENT LOADING ON THE SEAFLOOR [J].
CROUGH, ST .
JOURNAL OF GEOPHYSICAL RESEARCH, 1983, 88 (NB8) :6449-6454
[20]   Buried inset-valleys in the Eastern Yilgarn Craton, Western Australia: Geomorphology, age, and allogenic control [J].
de Broekert, P ;
Sandiford, M .
JOURNAL OF GEOLOGY, 2005, 113 (04) :471-493