Alan R. A. Aitken

University of Western Australia | UWA · School of Earth and Environment

High‐quality aeromagnetic data are important in guiding new knowledge of the solid earth in frontier regions, such as Antarctica, where these data are often among the first data collected. The difficulties of data collection in remote regions often lead to less than ideal data collection, leading to data that are sparse and four‐dimensional in natu...

Detrital provenance methods aid to understand ice sheet conditions in the past, often seeking to define the location of the eroding ice sheet margin. To support interpretation, we develop a probabilistic approach to predict detrital production linked to changing ice sheet conditions. The approach is applied in western Wilkes Land, Antarctica. Consi...

The Antarctic Ice Sheet (AIS) is out of equilibrium with the current anthropogenic‐enhanced climate forcing. Paleo‐environmental records and ice sheet models reveal that the AIS has been tightly coupled to the climate system during the past, and indicate the potential for accelerated and sustained Antarctic ice mass loss into the future. Modern obs...

East Antarctica remains one of the few continental regions on Earth where an understanding of the origin and causal processes responsible for topographic relief is largely missing. Low‐temperature thermochronology studies of exposed Precambrian basement revealed discrete episodes of cooling and denudation during the Paleozoic–Mesozoic; however, the...

The view from the south is, more than ever, dominated by ominous signs of change. Antarctica and the Southern Ocean are intrinsic to the Earth system, and their evolution is intertwined with and influences the course of the Anthropocene. In turn, changes in the Antarctic affect and presage humanity's future. Growing understanding is countering popu...

Knowledge of the evolution of ancient cratonic lithospheres underpins our understanding of Precambrian Earth. The Yilgarn Craton has exceptionally well-preserved Archean geology, with juvenile crust formation and major orogenesis concluding in the Neoarchean, and a stabilised upper-crustal architecture developing before 2.42 Ga. However, in an appa...

Over the past 60 years, scientists have strived to understand the past, present and future of the Antarctic Ice Sheet. One of the key components of this research has been the mapping of Antarctic bed topography and ice thickness parameters that are crucial for modelling ice flow and hence for predicting future ice loss and ensuing sea level rise. S...

Antarctica preserves Earth’s largest ice-sheet, which in response to climate warming, may lose ice mass and raise sea level by several metres. The ice-sheet bed exerts critical controls on dynamic mass loss through feedbacks between water and heat fluxes, topographic forcing, till deformation and basal sliding. Here we show that sedimentary basins...

The Mangaroon Orogeny (1695–1620 Ma) recorded in the Capricorn Orogen of Western Australia involved magmatism, deformation and metamorphism that are described mostly in the west of the orogen. New geophysical modelling indicates the orogeny also had significant influence in the eastern orogen from the interpreted presence of the magnetic Durlacher...

Antarctica preserves Earth’s largest ice sheet which, in response to climate warming, may lose ice mass and raise sea level by several metres. The ice-sheet bed exerts critical controls on dynamic mass loss through feedbacks between water and heat fluxes, topographic forcing and basal sliding. Here we show that through hydrogeological processes, se...

We present a fast inversion algorithm tailored for high-resolution potential field (gravity or magnetic) anomaly maps. The algorithm design objectives are to optimize performance with respect to the size of problem that can be solved and computation speed. It is based on a finite element method (FEM) discretization of both the inversion and forward...

The interaction of structure development and magmatism in rift-settings provide systemic controls on the emplacement of ore deposits both during rifting and subsequently, and a knowledge of these may help to predict better the likely locations of major deposits. The Paleoproterozoic Bryah Rift Basin includes substantial mafic magmatism and deep-cru...

Airborne electromagnetic (AEM) survey data are typically inverted with one-dimensional (1D) AEM algorithms because 1D approaches are efficient methods for calculating subsurface conductivity and thickness variations. However, 1D AEM inversion algorithms are known to perform poorly in regions where the geology is 2D or 3D. In 2013, a regional-scale...

The Australian continent is composed of several geologic provinces, showing a general age progression from Archean in the west to Phanerozoic in the east. The lithospheric heterogeneity and complex tectonic history of this region make it a key area for studying the thermal and rheological structure of the geological provinces and testing the influe...

To discern temperature and compositional variations of the Australian upper mantle, we apply an integrative technique, which jointly interprets seismic tomography and gravity data. The final thermal model, obtained by changing the upper mantle composition according to the density variations, shows temperatures higher by 100–150°C in the Archean and...

Opening up greenfields regions for mineral exploration programs is facilitated through understanding their mineral prospectivity. The Capricorn Orogen in Western Australia can be considered such a greenfieldsdominated region, that hosts several mineral occurrences or deposits, but only a few have been mined extensively. Mineralisation in much of th...

Remotely sensed hyperspectral datasets were integrated with petrographic data to map the distribution of sedimentary rocks in order to infer grain size variations within the siliciclastic, Paleoproterozoic Bresnahan Group in Western Australia. Finer sandstones have greater compositional variation compared to coarser sandstones, with higher modal pr...

Gravity and 3D modelling combined with geochemical analysis examine the subsurface within and below the poorly exposed Palaeoproterozoic Yerrida Basin in central Western Australia. Understanding the structure of a region is important as key features indicating past geodynamic processes and tectonic activity can be revealed. However, in stable, post...

Abstract. Gravity and three-dimensional modelling combined with geochemical analysis are used to examine the subsurface within, and below the poorly exposed Paleoproterozoic Yerrida Basin in central Western Australia. Understanding the structure of a region is important as key features indicating past geodynamic processes and tectonic activity can...

The Antarctic Ice Sheet (AIS) holds the largest potential source of sea-level rise in a warming world. Remote sensing observations of the change in AIS mass reveals that it is only just beginning to respond to anthropogenic climate warming. Estimates of AIS contribution to sea-level rise to the year 2100 have continued to evolve since the Intergove...

The view from the south is, more than ever, dominated by ominous signs of change. Antarctica and the Southern Ocean are intrinsic to the Earth system, and their evolution is intertwined with and influences the course of the Anthropocene. In turn, changes in the Antarctic affect and presage humanity's future. Growing understanding is countering popu...

Key Points Microgravity monitoring was applied to understand hydrology of Kings Park, Perth, Western Australia. Results delineate seasonal to interannual changes in total water storage from rainfall, ecological usage and groundwater fluxes. A potential dependence of water storage on Indian Ocean Dipole and El Niño Southern Oscillation conditi...

The Challenge Although known to host world-class mineral deposits, the Eastern Yilgarn Craton and Albany-Fraser Orogen are largely covered by sediments that post-date mineralisation and shield the highly-endowed regional geology from view. Recognising mineralisation through this cover to target exploration investment effectively requires the deve...

Lower crustal flow zones occur in large and hot orogens and rifts, where they occur in association with large areas possessing high gravitational potential energy (GPE) and low lower crust viscosity. Lower crustal flow zones are also known from regions where neither the rheological nor GPE conditions are sufficiently well developed for widespread f...

Basins along the northern margin of the Yilgarn Craton developed in response to extensional and compressional processes during the Paleoproterozoic. Early extension resulted in the formation of the Yerrida Basin as a large single basin over the northern Yilgarn Craton. Subsequent rifting led to voluminous volcanism in the northern part of the basin...

Since March 2015 the UWA in collaboration with the BGPA has conducted a time-lapse microgravity study of groundwater storage in Kings Park. Data collection has focused on seasonal to inter-annual change, with bi-monthly measurements extending across multiple days. Relative measurements are taken with a Scintrex CG-5 gravity meter and are referred t...

Geological, geophysical and remote sensing data have been used in the northweast Capricorn Orogen to map crustal scale structures beneath Paleoproterozoic Basins that may have focused mineralising fluids. The interpretations were largely based on upwardly continued bouguer gravity and magnetic data, then tested using petrophysically constrained for...

Exploration programs involve long, multi-branched decision pathways with many potential outcomes from a single starting point. Critical decisions along this pathway include the choice of the area(s) in which to explore, and the choice to acquire new data sets to assist in exploration. Included in this is a factoring of risks, including the technica...

The second generation Antarctic magnetic anomaly compilation (ADMAP-2) for the region south of 60oS includes some 3.5 million line-km of aeromagnetic and marine magnetic data that more than doubles the initial map’s near-surface database. For the new compilation, the magnetic datasets were corrected for the International Geomagnetic Reference Field...

The 1:10,000,000 scale second generation crustal magnetic anomaly map for the Antarctic region south of 60°S (ADMAP-2) was produced from near-surface terrestrial, airborne and marine magnetic observations compiled by the Antarctic Digital Anomaly Project (ADMAP). This international working group was established in 1995 in accordance with scientific...

Understanding how Large Igneous Provinces (LIPs) formed in the Proterozoic is subject to several challenges, including incomplete geological exposure, deformations from subsequent reworking and the lack of strong geophysical signals from the associated thermal perturbations. Here we apply a seismically-constrained gravity inversion method to the Wa...

Understanding how the Australian continent came together requires an understanding of structure in all levels of the lithosphere. Deep seismic reflection profiles across several Proterozoic orogens have revealed entirely buried tectonic elements, termed seismic provinces. Although undoubtedly important, the nature of these seismic provinces is typi...

An integrated interpretation of the east Kimberley, northern Western Australia was completed to determine mineral prospectivity, and was centred on a portion of a magnetotelluric (MT) survey conducted across the entire Kimberley Craton and surrounding orogens. A structural geophysical interpretation used potential field data, and was constrained by...

A regional tectonic model is presented for the formation and evolution of Paleoproterozoic basins over the northern Yilgarn Craton, integrating new and published regional geological, geochronological, geochemical and geophysical data. The basins formed as a response to both extensional and compressional processes in the early Paleoproterozoic along...

The cratonisation of Western Australia during the Proterozoic overlapped with several key events in the evolution of Earth. These include global oxidation events and glaciations, as well as the assembly, accretionary growth, and breakup of the supercontinents Columbia and Rodinia, culminating in the assembly of Gondwana. Globally, Proterozoic miner...

Combined mapping of variations in sedimentary basin fill composition and a structural interpretation is a step towards defining significant crustal scale structures and developing tectonic models in basin dominated terranes. The Bresnahan Group, part of the siliclastic Bresnahan Basin in the Capricorn Orogen was deposited in one such region. New ge...

An integrated interpretation of potential field and magnetotelluric (MT) data was performed in the east Kimberley, northern Western Australia Structural interpretation of potential field data was constrained by geological field observations, petrophysics, remote-sensing and an understanding of the tectonic history of the region. Forward modelling o...

Sedimentary basins beneath the East Antarctic Ice Sheet (EAIS) have immense potential to inform models of the tectonic evolution of East Antarctica and its ice-sheet. However, even basic characteristics such as thickness and extent are often unknown. Using airborne geophysical data, we resolve the tectonic architecture of the Knox Subglacial Sedime...

The Totten Glacier is the outlet for one of the most voluminous catchments in East Antarctica, and shows signs of vulnerability to change. The upstream portions of this catchment include the topographic lows of the Sabrina Subglacial Basin (SSB) and the Aurora Subglacial Basin (ASB), which are surrounded by highland regions. The SSB and ASB each ar...

Climate variations cause ice sheets to retreat and advance, raising or lowering sea level by metres to decametres. The basic relationship is unambiguous, but the timing, magnitude and sources of sea-level change remain unclear; in particular, the contribution of the East Antarctic Ice Sheet (EAIS) is ill defined, restricting our appreciation of pot...

The east Kimberley region contains well-preserved tectonic structure dating back to the Earth’s most significant stage of continental growth: the assembly of the Nuna supercontinent. An integrated geological–geophysical investigation of this region has been conducted and reveals insight into its tectonic evolution, including potential influence of...

Predicting realistic targets in underexplored regions proves a challenge for mineral explorers. Knowledge-driven prospectivity techniques assist in target prediction, and can significantly reduce the geographic search space to a few locations. The mineral prospectivity of the underexplored west Kimberley region was investigated following interpreta...

Understanding the regional context of mineral prospectivity is essential for opening areas to effective exploration. The Halls Creek Orogen in Western Australia, is one such region. Here we have completed a multi-commodity mineral systems analysis, which we have used as a basis for the production of semi-automated prospectivity models. Known minera...

The idea for design of the programming tool escipt is to provide scientists with an easy to use software environment in which complex mathematical models can be quickly implemented and tested. Models are developed using the programming language python. Python is easy to learn even for programming novices, and now widely available an all compute pla...

This report is a public domain document that can be downloaded directly from the Geological Survey of Western Australia website: http://dmpbookshop.eruditetechnologies.com.au/product/prospectivity-analysis-of-the-halls-creek-orogen-western-australia-using-a-mineral-systems-approach.do

The subglacial landscape of Princess Elizabeth Land (PEL) in East Antarctica is poorly known due to a paucity of ice-thickness measurements. This is problematic given its importance for understanding ice-sheet dynamics, and landscape and climate evolution. To address this issue, we describe the topography beneath the ice sheet by assuming ice-surfa...

Density is a key driver of tectonic processes, but it is a difficult property to define well in the lithosphere because the gravity method is non-unique, and because converting to density from seismic velocity models, themselves non-unique, is also highly uncertain. Here we use a new approach to define the lithospheric density field of Australia, c...

GIS-based 2D prospectivity modelling of three greenfields geological regions of Western Australia, namely, the West Arunta Orogen, West Musgrave Orogen and Gascoyne Province, was implemented for a range of deposit types including orogenic and intrusion-related gold, volcanic sediment-hosted base-metal sulfides, magmatic nickel-copper and magmatic p...

The Australian continent records c. 1860–1800 Ma orogenesis associated with rapid accretion of several ribbon micro-continents along the southern and eastern margins of the proto-North Australian Craton during Nuna assembly. The boundaries of these accreted micro-continents are imaged in crustal-scale seismic reflection data, and regional gravity a...

Totten Glacier, the primary outlet of the Aurora Subglacial Basin, has the largest thinning rate in East Antarctica. Thinning may be driven by enhanced basal melting due to ocean processes, modulated by polynya activity. Warm modified Circumpolar Deep Water, which has been linked to glacier retreat in West Antarctica, has been observed in summer an...

From the Mesoproterozoic to Cambrian, Australo-Antarctica was characterised by tectonic reconfiguration as part of the supercontinents Columbia, Rodinia and Gondwana. New tectonic knowledge of the Wilkes Land region of Antarctica allows Australo-Antarctic tectonic linkages to be resolved through reconstruction into ca. 160 Ma Gondwana. We also reso...

International collaborative exploration over the last decade has revealed East Antarctica as a geologically diverse continent underlying an ice sheet with significant sea level potential, parts of which are currently undergoing rapid change. The Wilkes and Aurora Subglacial Basins (WSB and ASB), two of the largest reservoirs of sea level potential...

The Totten Glacier Ice Shelf (TGIS) is the primary outlet of the Aurora Subglacial Basin, draining 6.9 meters of eustatic sea level potential into the Sabrina Coast (SC) alongside the Moscow University Ice Shelf that fringes the coastline. The TGIS and surrounding grounded ice has the largest thinning signal in East Antarctica and the nature of the...

Two near-orthogonal magnetotelluric (MT) traverses were conducted through the eastern part of the Capricorn Orogen (totalling 350 km in length with 42 broadband MT recordings) in order to elucidate the crustal-scale architecture of this region. Standard processing methods were used for MT data, including robust remote-reference algorithms based on...