Seismic wavespeeds and attenuation in upper-mantle rocks: a laboratory study of the effect of partial melting. The influence of partial melting on the seismic properties of the Earth's upper mantle will be explored through a laboratory study. Synthetic rock specimens consisting of the upper-mantle mineral olivine and a small proportion of basaltic magma will be prepared and their grain-scale melt distribution will be characterised. The seismic properties of these materials will be measured at ....Seismic wavespeeds and attenuation in upper-mantle rocks: a laboratory study of the effect of partial melting. The influence of partial melting on the seismic properties of the Earth's upper mantle will be explored through a laboratory study. Synthetic rock specimens consisting of the upper-mantle mineral olivine and a small proportion of basaltic magma will be prepared and their grain-scale melt distribution will be characterised. The seismic properties of these materials will be measured at high temperatures and seismic frequencies with novel locally developed equipment. Comparison with melt-free equivalents will allow the influence of the added magma to be quantified, allowing robust interpretation of seismological models of Earth structure with implications for its chemical and dynamical evolution.Read moreRead less
The seismic signature of crustal fluids. Fluids are expected to profoundly modify the seismic properties of the cracked rocks of Earth's upper crust (to depths of about 15 km) but there are so far few relevant laboratory measurements. Through the development and application of novel experimental techniques we plan to build a better laboratory-based understanding of the seismic properties of fluid-saturated crustal rocks. The outcome will be an improved capacity to monitor the presence of fluid ....The seismic signature of crustal fluids. Fluids are expected to profoundly modify the seismic properties of the cracked rocks of Earth's upper crust (to depths of about 15 km) but there are so far few relevant laboratory measurements. Through the development and application of novel experimental techniques we plan to build a better laboratory-based understanding of the seismic properties of fluid-saturated crustal rocks. The outcome will be an improved capacity to monitor the presence of fluids in diverse situations ranging from geothermal power generation and waste disposal to earthquake fault zones. Read moreRead less
The Role of Hydrous Fluids in Fault Processes: An Experimental Study. The proposed project seeks to understand how hydrothermal reactions in fault zones affect various physical properties such as fault strength and permeability. The project will be conducted by performing high pressure experiments which simulate natural conditions. I will also develop new analytical techniques to characterize the microstructural evolution of faults, with a focus on understanding how any changes alter the hydrolo ....The Role of Hydrous Fluids in Fault Processes: An Experimental Study. The proposed project seeks to understand how hydrothermal reactions in fault zones affect various physical properties such as fault strength and permeability. The project will be conducted by performing high pressure experiments which simulate natural conditions. I will also develop new analytical techniques to characterize the microstructural evolution of faults, with a focus on understanding how any changes alter the hydrologic behaviour of the fault. This study will shed much needed information related to the mechanisms of earthquake nucleation, and to the formation mechanism of fault-hosted gold deposits.Read moreRead less
High-temperature Elastic Wave Speeds of Mantle Minerals and their Seismological Implications. Laboratory measurements of elastic wave speeds are critical for the interpretation of seismological models for the Earth's deep interior. During the past several years, research groups at ANU and Stony Brook University have separately been proving novel experimental techniques for measurement of the temperature dependence of elastic wave speeds. Now a timely collaboration is proposed in which we would ....High-temperature Elastic Wave Speeds of Mantle Minerals and their Seismological Implications. Laboratory measurements of elastic wave speeds are critical for the interpretation of seismological models for the Earth's deep interior. During the past several years, research groups at ANU and Stony Brook University have separately been proving novel experimental techniques for measurement of the temperature dependence of elastic wave speeds. Now a timely collaboration is proposed in which we would exploit access to similar temperature ranges under two very different pressure regimes to examine the mixed pressure-temperature dependence of wave speeds that is so critical for the inference of chemical composition, mineralogical make-up, and temperature variations within the Earth's mantle.Read moreRead less
NUMERICAL MODELS OF PLATE TECTONICS, MANTLE CONVECTION AND SLAB DYNAMICS WITH EVOLVING FAULTS. We plan to develop a method for simulating large-scale
geological structures with a much improved treatment
of tectonic faults in 3D.
Current computer models have sharp geological faults at plate
boundaries represented by broad, blurred zones. New techniques
for modeling cracks in engineering structures will be scaled up to
the whole Earth.
This will help us to understand how the Earth's p ....NUMERICAL MODELS OF PLATE TECTONICS, MANTLE CONVECTION AND SLAB DYNAMICS WITH EVOLVING FAULTS. We plan to develop a method for simulating large-scale
geological structures with a much improved treatment
of tectonic faults in 3D.
Current computer models have sharp geological faults at plate
boundaries represented by broad, blurred zones. New techniques
for modeling cracks in engineering structures will be scaled up to
the whole Earth.
This will help us to understand how the Earth's plates move and
interact now and in the past and how the structure of the continents
arose.
Not only is this intrinsically interesting, it
will also be of immediate practical benefit to geological modelers.Read moreRead less
From crust to core: probing the heterogeneity of the Earth with seismic arrays. Seismic array deployments will be used for a variety of studies including tomographic mapping of upper mantle structure, coda analysis for crustal properties and delineation of deeper Earth structure. The high resolution information on crustal and upper mantle structure will provide important detail on the building blocks of the Australian plate at depth. This class of information helps to refine our understanding o ....From crust to core: probing the heterogeneity of the Earth with seismic arrays. Seismic array deployments will be used for a variety of studies including tomographic mapping of upper mantle structure, coda analysis for crustal properties and delineation of deeper Earth structure. The high resolution information on crustal and upper mantle structure will provide important detail on the building blocks of the Australian plate at depth. This class of information helps to refine our understanding of the way that the Australian continent has been assembled with regard to the interaction of the crust and mantle and the emplacement of mineral resources.Read moreRead less
Linkage Infrastructure, Equipment And Facilities - Grant ID: LE0668155
Funder
Australian Research Council
Funding Amount
$350,000.00
Summary
Instrumentation for combined seismic and electromagnetic Earth sounding. The set of geophysical recorders will provide the means to enhance understanding of the structure of the Australian continent in 3-D. The interpretation of multiple images of Earth structure will help to link features in the crust and mantle beneath, and provide controls on the evolution and assembly of the present continent, with a major contribution to possible geotransects as recommended in the 2003 National Strategic Pl ....Instrumentation for combined seismic and electromagnetic Earth sounding. The set of geophysical recorders will provide the means to enhance understanding of the structure of the Australian continent in 3-D. The interpretation of multiple images of Earth structure will help to link features in the crust and mantle beneath, and provide controls on the evolution and assembly of the present continent, with a major contribution to possible geotransects as recommended in the 2003 National Strategic Plan for the Geosciences. Combining seismic and electromagnetic methods will provide both geochemeical and geophysical constaints, e.g., on zones of alteration and shear with the potential for deep mineralisation. Read moreRead less
Precise location of earthquakes: combining arrival times with Coda Wave Interferometry. The location of earthquakes is important for improving our knowledge
of the contemporary plate tectonic regime, mapping of active crustal faults and quantifying risk posed to population centres and infrastructure. Precise relative location of micro-earthquakes also has important industrial applications, including mapping the extent of underground geothermal reservoirs, and in exploration for ore producing ....Precise location of earthquakes: combining arrival times with Coda Wave Interferometry. The location of earthquakes is important for improving our knowledge
of the contemporary plate tectonic regime, mapping of active crustal faults and quantifying risk posed to population centres and infrastructure. Precise relative location of micro-earthquakes also has important industrial applications, including mapping the extent of underground geothermal reservoirs, and in exploration for ore producing hydrothermal systems. This project will advance the field of earthquake location by introducing new techniques that will increase the amount of seismic information that can be used for both research and national monitoring purposes. Read moreRead less
CRATON EDGES AND SUTURES IN THE AUSTRALIAN MANTLE. A major seismic experiment using recording of distant earthquakes will be used to provide images of 3-D structure in the Earth's crust and mantle along the length of the edge of the Precambrian Australian Shield and across the suture between the South and North Australian cratons within the Shield. Seismic structures derived from different classes of geodynamic models will be compared with seismic results derived from a variety of styles of dat ....CRATON EDGES AND SUTURES IN THE AUSTRALIAN MANTLE. A major seismic experiment using recording of distant earthquakes will be used to provide images of 3-D structure in the Earth's crust and mantle along the length of the edge of the Precambrian Australian Shield and across the suture between the South and North Australian cratons within the Shield. Seismic structures derived from different classes of geodynamic models will be compared with seismic results derived from a variety of styles of data interpretation, including seismic tomography. The experiment will improve understanding of the range of physical processes associated with rifting and building of continents.Read moreRead less
Dynamics and Chemical Evolution of the Earth's Early Mantle. Preliminary numerical results demonstrate that the Earth's mantle may have been compositionally stratified early in its history through a novel interaction between compositional buoyancies and viscosity stratification. This result has important implications for the evolution of the crust and for the chemical and isotopic evolution of the mantle. It also complements recent geochemical evidence for the extraction of a basaltic componen ....Dynamics and Chemical Evolution of the Earth's Early Mantle. Preliminary numerical results demonstrate that the Earth's mantle may have been compositionally stratified early in its history through a novel interaction between compositional buoyancies and viscosity stratification. This result has important implications for the evolution of the crust and for the chemical and isotopic evolution of the mantle. It also complements recent geochemical evidence for the extraction of a basaltic component from the early upper mantle. It is proposed to explore the robustness of this phenomenon in two and three dimensions, its longer-term behaviour, and the evolution of the stratification as the mantle cools to its present condition.Read moreRead less