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Curtin University
Science Seminars

Jane Cunneen (Curtin) on ‘Basement influences on structural styles in the Bight Basin, southern Australia’

By Tim Johnson 24 October 2016 Applied Geology Comments off

Wed 26th September @ 12:00 pm, Rm 312.222 

The Bight Basin on the southern margin of Australia is nearly 2000 km wide from west to east and overlies a number of different basement terranes including the Albany-Fraser Orogen in the west and the Gawler Craton in the east.

Terrane boundaries in the onshore portion of the southern margin of Western Australia have been considerably refined in recent years (e.g. Spaggiari et al., 2015), and many terrane linkages between Australia and Antarctica have been proposed (e.g Fitzsimons, 2003; Jacob & Dyment, 2014), yet the extension of these boundaries immediately offshore is poorly constrained.  In the shallower parts of the Bight Basin, basement is well imaged on seismic data, but many parts of the basin are too deep for imaging with conventional seismic data and thus the basement structure in these areas remains unclear.

This study uses a combination of potential field and seismic data to suggest offshore continuation of a number of key basement trends and provide better constraints on the structural styles observed in the overlying sedimentary sequences within the Bight Basin.

Giada Iacono Marziono on Assimilation of sulfate and carbonaceous rocks: application to the Noril’sk-Talnakh region.

By Katy Evans 19 September 2016 Applied Geology Comments off

Curtin Applied Geology Seminar

Wed 21st September

@ 12 pm

Rm 312.222

Giada Iacono Marziono

Institut des Sciences de la Terre d’Orléans

Assimilation of sulfate and carbonaceous rocks: experimental study, thermodynamic modeling and application to the Noril’sk-Talnakh region.  

Most of the intrusions in the Noril’sk-Talnakh region (Siberia) are hosted in thick sedimentary sequences, including abundant evaporitic and terrigenous sedimentary rocks. Only three out of at least 22 mafic-ultramafic intrusions in the Noril’sk and Talnakh ore districts contain unusually thick massive sulfide deposits, which represent one of the world’s largest economic concentrations of Ni, Cu and PGE. The interaction of Siberian magmas with sulfate and organic matter-rich sedimentary rocks has been proposed as a possible mechanism for the origin of these exceptional sulfide deposits but never fully investigated. We conducted interaction experiments at conditions relevant to the emplacement of Noril’sk type intrusions to simulate the assimilation of sulfate and/or organic compounds by ultramafic magmas. We clarify how sulfate and organic matter assimilation occur in mafic-ultramafic magmas, affecting magma composition, crystallization and sulfide saturation. Gas-melt thermodynamic calculations were also employed to quantify the effect of these assimilations on the redox conditions and the S content of the magma, and investigate the role of temperature, pressure, and initial gas content of the magma in the assimilation process. Experimental and modeling results have been applied to the Noril’sk-Talnakh district to explain the occurrence of massive sulfide deposits, but also disseminated sub economic ones and barren intrusions. We conclude that exceptional conditions favoring substantial assimilation of sediments are needed to generate Noril’sk-Talnakh exceptional ore deposits.

Bio Details

Giada is an experimental petrologist currently working at the Institut des Science de la Terre d’Orléans. She did her PhD between the University of Palermo in Italy, and the BGI of Bayeruth in Germany on the degassing of phonolitic magmas. Since then she has been working on the behavior of volatiles in magmas (solubility and degassing of H2O, CO2, S, noble gases, halogens) and on the assimilation of volatile-rich sedimentary rocks. She joined the CNRS (French national center for scientific research) in 2011 and started working on the role of magma-sediment interactions and volatiles in ore processes.

Applied Geology Seminar – 7th September – Daniel Viete on timescales of metamorphism

By Katy Evans 2 September 2016 Applied Geology Comments off

Wed 7th September

@ 12:00 pm

Rm 312.222 

Daniel Viete (John Hopkins University)

Investigating the origins of rhythmic major-element zoning in HP/LT garnets from worldwide subduction mélanges

Rhythmic major-element zoning has been documented in garnets from high pressure/low temperature (HP/LT) lenses within a number of worldwide subduction mélanges (e.g. California, Chinese Tianshan, Cuba, Greek Cyclades, Guatemala, Japan, Venezuela). The origin of these features may have implications for the nature of subduction-zone processes.

Conditions of rhythmic zoning acquirement in HP/LT garnets of California and Venezuela were investigated by use of Raman and synchrotron Fourier transform infrared (FTIR) microspectroscopy, and thermodynamic modelling of phase equilibria.

Quartz-in-garnet Raman barometry reveals varying P—on the order of 100­–300 MPa, over radial distances of 10s of µm—in association with the high-Mn (and low-Mg) bands that define the fine-scale rhythmic zoning. Results from FTIR microspectroscopy demonstrate association between the high-Mn bands and locally depressed (structural) OH and elevated (molecular) H2O concentrations. The microspectroscopy results suggest changes in P and fluid activity attended development of the rhythmic garnet zoning.

Perple_X modelling of phase equilibria shows that, for specific rock chemistry and subduction P–T conditions, garnet modal abundance is extremely sensitive to changes in P and T (e.g. 10–30 vol.% growth/dissolution for DP = 300 MPa or DT = 25 °C). Rhythmic major-element zoning may reflect P- and/or fluid-driven cycles of garnet stability–instability during subduction. The steep compositional gradients that define the rhythmic major-element zoning limit time scales at subduction T, requiring that individual stability–instability cycles were extremely brief.

Seismic cycles and/or porosity waves represent ephemeral phenomena capable of accounting for development of rhythmic major-element zoning in HP/LT garnet, during subduction, as a result of fluctuations in both P and fluids. Metamorphic rocks may well carry detailed records of the catastrophism that punctuates longer-term tectonometamorphic processes.

Richard Ernst (Carleton University, Ottawa & Tomsk Ste University, Siberia) on: ‘Frontiers in Large Igneous Province Research’

By Tim Johnson 5 August 2016 Applied Geology Comments off

Wed 10th August @ 12:45 pm, Rm 312.222 

Abstract

Large Igneous Provinces (LIPs) represent large volume (>0.1 Mkm3; frequently above >1 M km3), mainly mafic (-ultramafic) magmatic events of intraplate affinity, that occur in both continental and oceanic settings, and are typically of short duration (<5 m.y.) or consist of multiple short pulses over a maximum of a few 10s of m.y. They comprise volcanic packages (flood basalts), and a plumbing system of dykes, sills and layered intrusions, and can be associated with silicic magmatism, carbonatites and kimberlites. They occur with a frequency of 1 per 20-30 myr back to 2.5 Ga and are also present in the Archean. LIP analogues are also present on Mars and Venus and other planetary bodies.  While a variety of origins are offered for LIPs, current data are increasingly favouring a mantle plume origin. LIPs are causally linked with continental breakup, global climate/environmental change including extinction events, and ore deposits of a variety of commodity types. In this lecture I will provide a tour of all aspects of LIPs with a focus on latest insights and current research frontiers.

Biography

Dr. Richard E. Ernst was born in Philadelphia, USA and grew up in St. Louis, Missouri. After finishing undergraduate work at Wesleyan University in 1978, he was attracted north to Canada by geological field research, and he received an MSc from the University of Toronto in 1981, and PhD from Carleton University in 1989. He then worked until 2003 on contracts mainly through the Geological Survey of Canada. At this point he started his own consulting firm “Ernst Geosciences”, and also became an Adjunct Professor at Carleton University.  He has been co-leader (2003-2013), and leader (2013-present) of the Large Igneous Provinces (LIPs) Commission of IAVCEI (International Association of Volcanology and Chemistry of the Earth’s Interior); see the website which includes the regular feature, LIP of the Month [ http://www.largeigneousprovinces.org/LOM ].  In 2009, Dr. Ernst co-launched a consortium of industry sponsors contributing 1.5 million dollars toward using the LIPs record to reconstruct the arrangement of crustal blocks within supercontinents back through time, funding which was also partly matched by government grants.

Throughout his research career and in his current position as Scientist in Residence at Carleton University, Ottawa, Canada, Dr. Ernst has been focussed on Large Igneous Provinces and especially their regional feeder dyke swarms. In fall 2014 Dr. Ernst’s comprehensive book on Large Igneous Provinces was published by Cambridge University Press. In April 2016 he published in Nature Geoscience  on using the LIPs record to demonstrate a connection between southern Siberia and northern Laurentia throughout much of the Proterozoic. He is responsible for the LIPs component of the new IGCP 648 Project “Supercontinent Cycles and Global Geodynammics”. Dr. Ernst is the author on more than 140 refereed scientific publications.

Amaury Pourteau (Curtin) on: ‘Duration of tectonic processes constrained by Lu–Hf garnet geochronology’

By Tim Johnson 26 July 2016 Applied Geology Comments off

Wed 3rd August @ 12 pm, Rm 312.222 

Garnet has become a key target for geochronological studies. Technical and analytical advances in the past two decades have made garnet geochronology a powerful approach to constrain the evolution of metamorphic rocks. Not only may precise metamorphic dates be obtained from multi-point isochron diagrams but also the tempo of garnet growth can be explored taking account of the scatter in isotopic data or using micro-sampling of large crystals. We used lutetium–hafnium (Lu–Hf) garnet geochronology to investigate the dynamics of transient tectonic environments related to the closure history of the Neotethys Ocean in western Anatolia. Geochronology was applied following two approaches. Comparing the metamorphic evolution of contrasting HP/LT oceanic rocks in a subduction complex reveals 20-Myr-lasting active cooling of an ancient subduction interface following subduction inception. In addition, we micro-sampled sections along core-to-rim profiles of cm-sized garnet crystals formed during continental collision and show that Barrovian-type heating may last well over 15 Myr. Garnet geochronology therefore is useful for deciphering the duration to thermal, chemical and petrological processes, and may be used to reveal the pace of ‘proto-tectonic’ processes prevalent during the Proterozoic and earlier.

Jani Radebaugh (Brigham Young University) on: “Earth Analogue Studies for Planetary Landforms”

By Tim Johnson 18 July 2016 Applied Geology Comments off

Wed 20th July @ 12 pm, Rm 312.222 

Abstract: We are studying the surfaces of other planets at increasingly high resolution, effectively placing ourselves there as researchers. This necessitates a good understanding of processes and landforms we might see, studies of which are often much easier to perform on Earth, where we can walk around on the landforms and take samples. We have done studies of lava lakes in Vanuatu and Ethiopia to better understand lakes of lava on Jupiter’s moon Io, including their behavior over time and their temperatures. We are studying large megadunes of the deserts of Egypt, Namibia, the United Arab Emirates and the Western Outback of Australia to better understand the linear dunes covering almost 1/4 of the surface of Saturn’s moon Titan. Such analogue studies are not only providing new insights into our studies of other planets, but our planetary studies are feeding back on our understanding of landforms here on Earth.

Bio: Jani Radebaugh is a planetary scientist who specializes in the shapes and origins of landscapes in the solar system. She studies features on Earth’s surface, where it is possible to walk around on them and obtain samples, to gain insight into similar landforms and processes on other planets. Her current investigations include giant sand dunes, mountains, volcanoes, rivers and lakes on Saturn’s moon Titan from the orbiting Cassini spacecraft and actively erupting volcanoes and mountains on Jupiter’s moon Io from Galileo, Cassini, and Voyager spacecraft. She has done field work in the Egyptian Sahara, the Arabian peninsula, the Ethiopian Afar Rift Valley, Hawaii, the desert southwestern US, and Antarctica. Some of her field studies have been captured on film, including in the internationally syndicated How the Universe Works 3 series from Pioneer Productions in the UK. She obtained her PhD in planetary science from the University of Arizona’s Lunar and Planetary Laboratory, and she is now an associate professor of geological sciences at Brigham Young University. She seeks to understand how field studies on Earth, including work on big desert dunes and remote volcanoes, as well as meteorite searching in Antarctica, have helped us better understand processes in the outer solar system revealed by the myriad spacecraft orbiting, flying by, or landed on other planetary bodies.

Professor Paul Hoffman (Harvard University) on: “Snowball Earth and Biological Evolution”

By Tim Johnson 12 July 2016 Applied Geology Comments off

Mon 18th July @ 12 pm, Rm 312.222

The global climatic phenomenon known as Snowball Earth is arguably the most exciting and challenging discovery in geology in the last 35 years. It is inherently multidisciplinary: its recognition came from geology, its origin and predictive nature from climate dynamics, its verification from geochemistry and geochronology, and its legacy is geobiological.

Denis Fougerouse (Applied Geology, Curtin) on: ‘Using the state-of-the-art Australian microanalytical facilities for the study of ore deposits: case study of the refractory ores of the Obuasi giant gold deposit, Ghana’

By Tim Johnson 30 May 2016 Applied Geology Comments off

Wed 1st June @ 12 pm, Rm 312.222

Auriferous sulphides, most notably pyrite (FeS2) and arsenopyrite (FeAsS), are some of the most important strategic minerals on Earth because they host gold in many of the world’s major gold deposits. To increase our understanding of mineralisation processes, we combined atom probe microscopy, high-resolution secondary ion mass spectrometry (NanoSIMS), synchrotron X-ray fluorescence microscopy (XFM) mapping with the Maia detector and electron backscattered diffraction (EBSD) on arsenopyrite from the giant Obuasi gold deposit, Ghana.

The gold-rich arsenopyrites are shown to have undergone partial replacement by gold-poor, nickel-enrich arsenopyrite and indicate that large quantities of gold were remobilised via infiltration of only small volumes of fluid.

Atom probe tomography (APT) data revealed two types of gold distribution at the sub-micron scale in distinct sub-domains of the same arsenopyrite grain with, metallic gold nanoparticles (CAu = 724 ppm) and gold homogeneously distributed in the crystal lattice (CAu = 2,224 ppm). These results are not consistent with previous models that point to gold concentration as the key control on gold distribution, but instead we provide a new model for their formation.

These results provide fundamental information on gold distribution and remobilisation during ore deposit formation and deliver a framework for more efficient exploration strategies and metallurgical extraction of gold from sulfides.

Sasha Nemchin (Applied Geology, Curtin) on: ‘U–Pb zircon dating using ion probe imaging’

By Tim Johnson 25 May 2016 Applied Geology Comments off

Wed 25th May @ 12 pm, Rm 312.222

click image below to enlarge….

sasha

Ian Cockerill on: ‘Unconventional Resources. Identifying the sweetest-spots and quantifying potential using spatial analysis. An example from the Montney Play, Western Canada. ‘

By Tim Johnson 2 May 2016 Applied Geology Comments off

Wed 4th May @ 12 pm, Rm 312.222

The sharp fall in oil prices since mid-2014 has been driven by a number of factors, however empirical estimates indicate that supply (much more than demand) has accounted for the lion’s share of the latest plunge.   The increase in supply has come from a boom in North American unconventional oil production following significant technological advancements notably in pad based horizontal drilling and the use of hydraulic fracking.

Unconventional Resources are going to continue to play a significant role in the make-up of the worlds energy mix but, as you would expect, not all unconventional plays are created equal.  Significant heterogeneity exists in individuals plays.  With lower oil prices the poorer performing unconventional plays will see reduced activity (as we are starting to see) and drilling activity in the more robust plays will focus on the more commercially robust sweet-spots.  Identifying commercially robust sweet-spots in unconventional plays has never been more important.  Using the Montney Play as an example we’ll look at how GIS spatial analysis techniques have been used to quantify resource potential and high grade areas across the play in NE British Columbia, Canada.

The resource potential of the play has been characterised using calibrated reservoir characteristics and production performance from key wells, multi-attribute cross-plot analysis, and mapping of the key geological characteristics.  Stepping out from individual wellbores we will look at the key characteristics of the producing zones and then map them spatially to identify areas of interpreted common potential or productivity.

The Common ‘Recovery’ Segment Mapping approach takes principals from Common Risk Segment Mapping but applies them in estimating recovery potential, rather than risk, in the pervasive hydrocarbon system. The approach has resulted in an interpretation of Estimated Ultimate Recovery for the Montney zones across the play fairway.

Biography

Ian is a Geologist by background with 20 years of experience in the oil and gas industry.  He has worked globally with international assignments in South Africa, Canada, US, Singapore and most recently Australia.  He has worked extensively in both conventional and unconventional petroleum systems throughout the world and has a strong interest in the application of GIS in New Venture exploration.  He has previously held roles in new venture development and management for Hunt Oil Company and Apache Energy and has served as a director on numerous ASX company boards.  He is currently Managing Director of TSV Montney, a Montney focused exploration company operating in NE British Columbia.