Role of lithosphere in intra-continental deformation: Central Australia
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Role of lithosphere in intra-continental deformation: Central Australia. / Kennett, B. L. N.; Iaffaldano, Giampiero.
In: Gondwana Research, Vol. 24, No. 3-4, 11.2013, p. 958-968.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Role of lithosphere in intra-continental deformation: Central Australia
AU - Kennett, B. L. N.
AU - Iaffaldano, Giampiero
PY - 2013/11
Y1 - 2013/11
N2 - Since the Proterozoic, there has been a set of deformation cycles in central Australia culminating in the Alice Springs Orogeny around 400 Ma. These events occurred away from plate boundaries and involved extension as well as compression, although their precise history remains difficult to unravel from the geologic record. Much evidence of deformation is left in the central Australian crust, which features significant Moho topography and an associated gravity signal. In the past, several mechanical models invoked crustal thickening and considerable compression to explain these geophysical characteristics. However, it is hard to envisage extensive deformation affecting the crust alone, but leaving no deformation record in the sub-crustal lithosphere. In recent seismic tomography studies, there is continuous seismically-fast lithosphere in central Australia below depths of about 100 km. In this region, the uppermost lithospheric mantle is seismically slow, but exhibits no significant attenuation of seismic waves. These new constraints make simple crustal thickening unlikely to be the main mechanism to generate variations of the Moho depth in central Australia. Here we propose a mechanical model of deformation that involves the entire lithosphere. We make no strong assumptions about the history of deformation cycles. Our model does not require lithospheric thickening at any stage of the deformation cycle, and results in a present-day scenario compatible with shallow as well as deep constraints on the lithosphere structure.
AB - Since the Proterozoic, there has been a set of deformation cycles in central Australia culminating in the Alice Springs Orogeny around 400 Ma. These events occurred away from plate boundaries and involved extension as well as compression, although their precise history remains difficult to unravel from the geologic record. Much evidence of deformation is left in the central Australian crust, which features significant Moho topography and an associated gravity signal. In the past, several mechanical models invoked crustal thickening and considerable compression to explain these geophysical characteristics. However, it is hard to envisage extensive deformation affecting the crust alone, but leaving no deformation record in the sub-crustal lithosphere. In recent seismic tomography studies, there is continuous seismically-fast lithosphere in central Australia below depths of about 100 km. In this region, the uppermost lithospheric mantle is seismically slow, but exhibits no significant attenuation of seismic waves. These new constraints make simple crustal thickening unlikely to be the main mechanism to generate variations of the Moho depth in central Australia. Here we propose a mechanical model of deformation that involves the entire lithosphere. We make no strong assumptions about the history of deformation cycles. Our model does not require lithospheric thickening at any stage of the deformation cycle, and results in a present-day scenario compatible with shallow as well as deep constraints on the lithosphere structure.
KW - Central Australia
KW - Lithosphere
KW - Deformation
KW - Strength
U2 - 10.1016/j.gr.2012.10.010
DO - 10.1016/j.gr.2012.10.010
M3 - Journal article
VL - 24
SP - 958
EP - 968
JO - Gondwana Research
JF - Gondwana Research
SN - 1342-937X
IS - 3-4
ER -
ID: 138731822