|
Wednesday, 29th October 12 — 1 pm Rm 312.222 |
Andrea Agangi Applied Geology, Curtin University Gold deposition and remobilisation in the Archaean Witwatersrand basin, South Africa – A pyrite perspective Abstract
The origin of Au-U deposits in the Archaean Witwatersrand basin of South Africa is the subject of longstanding discussion. The two main models, the ‘modified placer’ and the ‘hydrothermal model’ imply opposite views on the formation of gold and pyrite in the metaconglomerates that host mineralisation. These two models have far reaching implications on the palaeoenvironmental conditions in the Archaean. New results presented in this talk provide evidence for the contemporaneous formation of sedimentary pyrite and gold deposition, and suggest a possible link between biogenic activity and gold accumulation in the Witwatersrand basin.
Biographical Details
Andrea Agangi has a background in igneous petrology and ore deposits geology. He received a PhD from CODES – University of Tasmania and then moved to the University of Johannesburg, South Africa, to study Archaean gold deposition and felsic magmatism in the Barberton Greenstone Belt and the Witwatersrand basin. He has recently joined Curtin University as a Post-Doctoral Fellow to work on the Proterozoic Capricorn Orogen. |
Curtin Applied Geology Seminar: Andrea Agangi, Curtin, on Gold in the Witwatersrand. Weds 29th October, 12pm.
Curtin Applied Geology Seminar: Mauro Geraldes, Brazil on the United Plates of South America. Weds 22nd October, 12pm.
|
Wednesday, 22nd October 12 — 1 pm Rm 312.222 |
Mauro Geraldes Rio de Janeiro State University, Brazil An overview of the Amazonian craton evolution: insights for paleocontinental reconstruction Abstract The Amazonian craton major accretionary and collisional processes may be correlated to supercontinent assembly developed at several times in the Earth history. Based on geologic, structural and paleomagnetic evidence, paleocontinent reconstructions have been proposed for Archean to younger times. Biographical Details Dr Mauro Cesar Geraldes is professor of Geochronology at Rio de Janeiro State University/ Brazil. He worked in the mineral industry in Amazonia region from 1996 to 1994 and got his master degree in 1996 in economic geology and PhD in geochemistry and geochronology from University of São Paulo (Brazil)/University of Kansas (EUA) in 2000. His current research is focused on crustal evolution and its temporal correlations with mineral deposits. |
Curtin Applied Geology Seminar: Weds 1st October: Geomorphology and Growth History of the Kimberley Coral Reefs
|
Wednesday 1st October 12 — 1 pm Rm 312.222 |
WAMSI/Curtin Coral Reef Geomorphology and Growth History Project Curtin University Geomorphology and Growth History of the Kimberley Coral Reefs The Kimberley in Northwest Australia is one of the last marine wilderness areas, and the coral reefs of the Kimberley Bioregion lie within a “biodiversity hotspot”. Situated along a subsiding complex Ria coast of 400 km length (thousands of kilometres long if the coastal complexity is considered) the Kimberley reefs are subject to macrotidal (11 m tides) conditions, frequent cyclones, high turbidity from active river systems, warm conditions, and frequent exposure for long periods. The reefs are poorly known, of recognised international significance, and in need of study. It has been argued from preliminary surveys that some of the reefs are veneers over rock platforms rather than true reefs.
The WAMSI/Curtin Coral Reef Geomorphology and Growth History project, one of the first geoscientific reef studies of the Kimberley Biozone, has as its objectives the establishment of a regional geodatabase of coral reefs based on remote sensing; determination of a Holocene record of reef growth; and establishment of internal reef architecture and growth history from shallow seismic (Boomer) surveys.
The seminar will consist of a series of short presentations by research team members, as follows:
1) Introduction and objectives: Lindsay Collins.
2) Title: A Large Scale Geomorphological and Surficial Cover Map of Nearshore Reefs in the Kimberley Coast, WA Authors: Moataz Kordi1,2, Lindsay Collins1,2 and Alexandra Stevens1,2 1 Department of Applied Geology, Curtin University, WA 2The Western Australian Marine Science Institution, Floreat, Australia, 6014 Abstract Coral reefs occur extensively along the north-western coast of Australia in the Kimberley Bioregion (KIM), forming major geomorphic features (landforms) along and just off the coast. These reefs have not been studied in as much detail as the offshore reefs and are poorly known. Geomorphological and surficial cover substrates and habitats maps of coral reefs provide significant information to both researchers and managers about the distribution and extent of reef landforms. This study aims to produce a large scale dynamic map in order to study reef spatial distribution patterns and to provide more information on geomorphological and surficial cover on reefs. Also other multiple data sources were integrated using Remote Sensing and Geographic Information System (GIS) to construct a geodatabase of the Kimberley reefs (ReefKIM) based on data fusion to verify results as well as to add value to the data in order to produce consistent, accurate, and useful geomorphic maps. The outcomes will facilitate better understanding of reefs in this region to develop a reef geomorphic classification scheme which describes reef evolution, classification and distribution of reefs by type. Moreover, they will provide a robust foundation to foster further studies in various disciplines beyond the scope of this study.
3) Title: Reef Geomorphology and Holocene Growth History of Cockatoo Island, Inshore Kimberley Bioregion, Northwest Australia. Authors: Tubagus Solihuddin1,4, Lindsay. B. Collins1,4, D. Blakeway2, Michael J. O’ Leary3,4 1Department of Applied Geology, Curtin University, Bentley, WA 6102 2Fathom 5 Marine Research, 17 Staines Street, Lathlain, WA 6100 3Department of Environment and Agriculture, Curtin University, Bentley, WA 6102 4The Western Australian Marine Science Institution, Floreat, Australia, 6014 Abstract This study describes reef geomorphology and Holocene (last 12,000 years) growth history in a macrotidal, high turbidity setting at Cockatoo Island, in the inshore Kimberley Bioregion, including geomorphic and associated habitat, chronology, Holocene and modern reef communities, nature of foundations, and type of reef accretion. The Holloway current, driven by the Indonesian throughflow, plays a major role in delivering nutrients and planktic biota for reef development. Preliminary study using aerial photography delineated, moving seaward across the reef flat, substrate of sediment, low and medium density intertidal coral cover. Towed camera observations confirm that live Porites and Faviids along with Sargassum sparsely colonise the intertidal coral zone, whilst branching Millepora and Porites cylindrical, which increase seaward, are present in the medium density intertidal coral zone. The Holocene reef unit investigated is ~13 m thick and of two distinct facies; domal and branching coral framestone units. Coral clasts are visually dominated by branching corals especially of the genus Acropora and massive corals including Porites. The contemporary live corals are not very common in the measured Holocene sections, suggesting that the Holocene reef communities lack reef flat habitat. The Holocene reflects mostly subtidal growth whereas the present reef is largely intertidal or very shallow subtidal. Compared to the same muddy-rich environment of the Great Barrier Reef (GBR), Cockatoo turbid reefs show broad similarities in terms of coral cover and accretion rates, but a contrast is between palaeoecological and contemporary reef communities, which are similar in the GBR but distinctly different at Cockatoo Island.
4) Title: Sub-bottom profiling and growth patterns of Kimberley coral reefs, North West Australia Authors: Giada Bufarale1,3, Lindsay B. Collins1,3, Michael O’Leary2,3, Moataz Kordi1,3, Tubagus Solihuddin1,3, Alexandra Stevens1,3 1Department of Applied Geology, Curtin University, Bentley, WA 6102 2Department of Environment and Agriculture, Curtin University, Bentley, WA 6102 3The Western Australian Marine Science Institution, Floreat, Australia, 6014 Abstract The Kimberley region is located on the north western continental margin of Australia and is characterised by unique and complex geology and geomorphology, significantly influenced by the macrotidal range systems (up to 11 m), which result in expansive intertidal zones. A total of 300 km of high-resolution shallow imaging data were acquired during a sub‐bottom profiling (SBP) study of various southern Kimberley reef settings. Acoustic datasets were collected with a Boomer SBP system covering reefs where remotely sensed images were previously used to produce geomorphic and substrate classification maps. A classification diagram has been developed on the basis of imaging of internal structures. Vertical and lateral differences were identified and categorised according to their shape and acoustic reflection characteristics along the hiatuses and internal reflectors. These new datasets have provided a better understanding of Quaternary reef growth. The pre-existing substrate has influenced the successive morphology of fringing reefs, intertidal platforms and platform reefs. Global sea-level change, controlled by ice age fluctuation events, provides a signal which is recorded in successive stages of the reef growth separated by hiatuses. Two acoustic reflectors can be consistently distinguished across the inner shelf reefs (Sundays Group, Buccaneer Archipelago and Montgomery Reef), marking the boundaries between Holocene reef (Marine Isotope Stage 1, MIS1, last 12,000 years) commonly 10-15 m thick, and MIS 5 (last 125,000 years) and an ancient Neoproterozoic rock foundation over which Quaternary reef growth occurred. Three acoustic reef units characterise the Adele Group offshore.
5) Collecting shallow sediment cores in macrotidal reef terrains: issues and techniques. Michael O’Leary.
Biographical Details
Lindsay Collins is a marine sedimentologist who has completed projects on continental shelf mapping of Australian shelves, and coral reef studies at the Abrolhos, Ningaloo, Scott Reef and the Rowley Shoals prior to establishing the Kimberley Coral Reef Study, with sponsorship from the WA Marine Science Institute (WAMSI).
Mick O’Leary research interests include reef geomorphology and palaeoclimate. He completed his PhD in Earth and Environmental Sciences at James Cook University, undertook post doc positions at Manchester Metropolitan and Boston Universities and now lectures in Coastal and Marine Science in The Department of Environment and Agriculture, Curtin University.
Giada Bufarale gained her MSC in Geology (University of Milano-Bicocca, Italy) and subsequently, started working as a marine geologist/geophysicist in a marine consultancy. In 2009 she joined the Applied Sedimentology, Coastal and Marine Geosciences group at Curtin University as a research assistant. She has carried out research on the stratigraphy and geomorphology of Shark Bay, the Swan River and Kimberley coast. In March 2014 she has started her PhD.
Moataz Kordi is a researcher in GIScience and remote sensing at KACST, Riyadh, SA. Currently he is a PhD candidate in the Department of Applied Geology, Curtin University. His study aims to construct a Geodatabase of the Kimberley reefs (ReefKIM) based on data fusion utilising GIS. Tubagus Solihuddin is a 3rd year-PhD Candidate in Department of Applied Geology, Curtin University in which he is studying “Holocene Reef Growth of the Inshore Kimberley Bioregion and Response to Sea-level Changes and Climate Impact. He has been working in Centre for Research and Development of Marine and Coastal Resources, The Republic of Indonesia since 2004 as a marine geologist.
Alexandra Stevens is a GIS Analyst with research interests in Coastal Management and Marine and Coastal Geoscience. She joined the Applied Sedimentology, Coastal and Marine Geosciences group in late 2005 as a research assistant and has completed projects in the Northern Agricultural Region, Ningaloo Reef, Scott Reef and Shark Bay. |
Curtin Applied Geology Seminar: Weds 24th Sept: David Mole: Komatiite volcanism and the early continents
|
|
Wednesday 24th September 12 — 1 pm Rm 312.222 |
David Mole CESRE, CSIRO Komatiite volcanism controlled by the hidden architecture of early continents David Mole
Abstract
The generation and evolution of the Earth’s continental crust has played a fundamental role in the development of the planet. Its formation modified the composition of the mantle, contributed to the establishment of the atmosphere and led to the creation of ecological niches important for early life. In this talk we show that in the Archean, the formation and stabilisation of continents also controlled the location, geochemistry and volcanology of komatiite volcanism. This talk uses the vast database of Sm-Nd isotopic data and U-Pb geochronology from the Yilgarn Craton to unravel the complex evolution of the various internal terranes. This is brought together in a holistic model for the development of the craton, and the fundamental role crustal evolution has played in the localisation, geochemistry and prospectivity of komatiites. Results show that in the early Earth, relatively small crustal ‘blocks’ analogous to modern micro-plates progressively developed to form larger continental masses and eventually the first cratons. This cratonisation process drove the hottest and most voluminous komatiite eruptions to the edge of established continental blocks. Fundamentally, this study demonstrates that the dynamic evolution of the early continents directly influenced the addition of deep mantle material to the Archean crust, oceans and atmosphere, while also providing a fundamental control on the distribution of major magmatic ore deposits. |
Curtin Applied Geology Seminar: 3rd September: Kate Trinajstic on the Imaging Beamline at the Australian Synchrotron
|
Wednesday 3rd September 12 — 1 pm Rm 312.222 |
Kate Trinajstic Curtin University, The Australian Synchrotron Imaging Beamline – not just for fossils Kate Trinajstic and Chris Hall (IMBL)
Abstract
Propagation phase-contrast X-ray microtomography (PPC-SRµCT) has been demonstrated to be an excellent technique for the non-destructive investigation of fossils, particularly in the areas of palaeohistology and soft tissue analyses. However, the imaging beamline at the Australian Synchrotron can be utilized in other areas of geoscience and is especially useful in the examination of samples with a high density. To date beamline scientists have assisted in studies on the porosity and permeability of coal and inclusions within volcanics. The beam line has three radiation enclosures for experiments, which cover use in a wide range of studies, from broad bandwidth, fine structured beam projects, to monochromatic (narrow bandwidth) large sample imaging. This presentation describes the status of the IMBL facility, it’s current use, and future prospects |
Curtin Applied Geology Seminar: Thursday 28th August, 1pm: Aaron Cavoisie on Shocked Hadean Zircons – Please note non-standard day, time and location.
|
|
Curtin Applied Geology Special Seminar
|
|
|
|
||
|
|
Thursday 29th August 1 – 2 pm Rm 312.207 |
Aaron Cavoisie Department of Geology, University of Puerto Rico Shocked Hadean Zircons
|
Curtin Applied Geology Seminar: Friday 29th August, 11am: Katarina Miljkovic on lunar impacts – Please note non-standard day, time and location.
|
|
Friday 29th August 11 — 12 pm Rm 312.207 |
Katarina Miljkovic (MIT) Massachusetts Institute of Technology The record of lunar impact basic formation from GRAIL mission gravity data |
Curtin Applied Geology Seminar: 26th August: Karol Czarnota (GA) on the Dynamic Topography of Australia – Note non-standard day and location
|
|
Tuesday 26th August 12 – 1 pm Rm 210.104 |
Karol Czarnota Geoscience Australia, Canberra, Australia Dynamic topography of Australia: Abstract It is generally agreed that plate motion is maintained by convective circulation of the Earth’s mantle. However, the detailed spatial and temporal pattern of this circulation is poorly known. Since dynamic topography is generated by the interplay between mantle convective circulation and plate motion, observational constraints should yield hitherto inaccessible insights into this convective process. Australia’s isolation from active plate boundaries and its rapid northward motion within a hotspot reference frame make it a useful natural laboratory. The present-day dynamic topography is best mapped offshore by measuring the residual depth of oceanic floor with respect to the well-known age-depth relationship. Onshore present-day dynamic topography can be estimated using the relationship between gravity and topography at wave-lengths >350 km. The temporal evolution of this topography can be constrained by interrogating passive margin architecture and inverting longitudinal river profiles for uplift histories. The results show the amplitude of Australian Dynamic topography is ±1 km. Southwestern Australia appears to have been emerging from the dynamic to- pography low associated with the Australian-Antarctic Discordance over the last ~50 Myrs whereas northern Australia has been drawdown by up to 700 m from an unperturbed elevation over the last ~10 Myrs. The Eastern Highlands were uplifted in two stages. The Great Escarpment appears to be the expression of present-day dynamic support, which grew during and immediately prior to Cenozoic volcanism. A discrete earlier phase of uplift is temporally associated with rifting leading to Tasman Sea floor spreading. This history of vertical motions constrains the passage of thermal anomalies beneath the Australian plate and is consistent with palaeocoastline elevations, longterm river incision rates, basin sequence stratigraphy and thermochronological studies. |
Curtin Applied Geology Seminar: 20th August: Aaron Hunter on Bizarre Crinoids
|
|
Wednesday 20th August 12 – 1 pm Rm 312.222 |
Aaron Hunter Department of Applied Geology A BIZARRE CRINOID FROM A METHANE SEEP IN THE LATE CRETACEOUS OF SOUTH DAKOTA, USA Abstract
Despite a rich and varied record, Mesozoic stalked crinoids are relatively rare in the Western Interior Seaway of North America compared to those found in Northern Europe. A unique example of Mesozoic stalked crinoid is described from cold methane seeps (hydrocarbon seep mounds also called “tepee buttes”) from the Upper Cretaceous (upper Campanian) of the Northern Great Plains of the United States; the first crinoids to be described from such an environment. The Late Cretaceous Western Interior Seaway has never before yielded any identifiable stalked crinoid remains. Nevertheless, there have been significant studies on both free living and stalked crinoids from other locations in the Upper Cretaceous of North America that provide a good basis for comparison. This distinct species is characterized by a tapering homeomorphic column with through-going tubuli, lacking any attachment disc. The arms are unbranched and pinnulate, with muscular and syzygialarticulations. The unique morphology of the column justifies the establishment of a separate family. A new suborder is also proposed as there exists no corresponding taxon within the Articulata that can accommodate all the characteristics of this new genus. This new crinoid shares many features with other members of the articulates, including bathycrinids, bourgueticrinids and guillecrinids within the OrderComatulida, as currently defined in the revised Treatise of Invertebrate Paleontology. Reconstructing the entire crinoid using hundreds of semi-articulated and disarticulated (well preserved) fossils, reveals a unique paleoecology and functional morphology specifically adapted to living within this hydrocarbon seep environment. |
|
|
|
|
|
|
|
|
Environment & Agriculture Seminar: Giovanni Di Vergilio ‘Characterising the transitional breaks that delineate biotic provinces and the spatial variation in their physical correlates’
Abstract:
Delineation of biota into distinct provinces of plant and animal assemblages and the identification of the disjunctions or breaks that separate them is a key focus in macroecology and biogeography and plays an important role in conservation planning. It is also informative to identify the geological, topographic and climatic factors that have influenced the formation of these structures. However, as traditionally defined, bioregions and breaks are characterised as uniform biotic provinces and delineated with solid, linear boundaries. Such representations do not reflect the true nature of the biotic patterns that they are intended to depict. The outer limits of biogeographic boundaries are areas where the distributions of different species groups can blend with one another, such that the breaks between adjacent bioregions are transitional zones. These ‘transitional’ breaks can change gradationally in some locations and more abruptly in others. Moreover, breaks and boundaries can change position over various timescales, e.g. ranging from the seasonal to semi-decadal.
A second issue is that identification of the environmental correlates influencing break formation does not take full account of how species-environment relationships change inconsistently across geographic space contingent upon the environmental nuances that vary between locations (i.e. spatial non-stationarity). Similarly, biophysical relationships exhibit anisotropic variation because ecological and physical processes change in different directions. For instance, anisotropic processes may be driven by both broad and fine-scale topographic and climatic gradients.
I introduce a spatially explicit, moving window analysis technique which can be used to measure the fine-scale, continuous variation in species compositional turnover and turnover in geology, topography and climate. These unidirectional moving window analyses are progressively rotated through 360° in order to capture the anisotropic variation in the rate of biotic and environmental turnover. This enables shared transitional breaks in aggregate biotic distributions to be identified, characterisation of their abrupt versus gradational transitions, as well as quantification of the non-stationary and anisotropic influence of environmental heterogeneity on their formation. I
apply this method to assess whether the biogeographic insights generated by broad-scale studies on the influence of environmental variability on biodiversity generalise to different spatial scales and locations. I then adapt and apply the method to conservation prioritisation.
