Geology & Geophysics publications
Permanent URI for this collection
Browse
Recent Submissions
Item Metadata only Cambrian Sauk transgression in the Grand Canyon region redefined by detrital zircons(Springer Nature, 2018) Karlstrom, K.; Hagadorn, J.; Gehrels, G.; Matthews, W.; Schmitz, M.; Madronich, L.; Mulder, J.; Pecha, M.; Giesler, D.; Crossey, L.The Sauk transgression was one of the most dramatic global marine transgressions in Earth history. It is recorded by deposition of predominantly Cambrian non-marine to shallow marine sheet sandstones unconformably above basement rocks far into the interiors of many continents. Here we use dating of detrital zircons sampled from above and below the Great Unconformity in the Grand Canyon region to bracket the timing of the Sauk transgression at this classic location. We find that the Sixtymile Formation, long considered a Precambrian unit beneath the Great Unconformity, has maximum depositional ages that get younger up-section from 527 to 509 million years old. The unit contains angular unconformities and soft-sediment deformation that record a previously unknown period of intracratonic faulting and epeirogeny spanning four Cambrian stages. The overlying Tapeats Sandstone has youngest detrital zircon ages of 505 to 501 million years old. When linked to calibrated trilobite zone ages of greater than 500 million years old, these age constraints show that the marine transgression across a greater than 300-km-wide cratonic region took place during an interval 505 to 500 million years ago—more recently and more rapidly than previously thought. We redefine this onlap as the main Sauk transgression in the region. Mechanisms for this rapid flooding of the continent include thermal subsidence following the final breakup of Rodinia, combined with abrupt global eustatic changes driven by climate and/or mantle buoyancy modifications.Item Metadata only Optically stimulated luminescence dating using quartz(Springer Nature, 2021) Murray, A.; Arnold, L.J.; Buylaert, J.-P.; Guérin, G.; Qin, J.; Singhvi, A.K.; Smedley, R.; Thomsen, K.J.Optically stimulated luminescence (OSL) signals from quartz can be used to determine when sedimentary archives were deposited. OSL dating uses the accumulation of energy stored in a crystal structure to measure time. This stored energy is absorbed from ionizing radiation, and is released (reset) by heat or daylight. The total specific energy (dose) absorbed since the last resetting is measured using OSL, and divided by the rate of storage (dose rate) to give the time elapsed from the last heating or daylight exposure. In this Primer, quartz OSL dating is introduced and the signal resetting processes outlined. We describe the origins and quantification of the dose rate and the daylight-sensitive OSL signal most appropriate to dose estimation. The most widely used dose measurement method is then discussed, together with quality-control procedures. A broad set of geological and archaeological studies are used to illustrate the wide range of potential applications, and we describe the challenges arising from different deposition environments and summarize evidence for the precision and accuracy of published ages. Uncertainties and minimum reporting are discussed together with methodological limitations, particularly when applied to young and old sediments. Finally, we highlight the anticipated future developments in the field.Item Open Access In-situ Lu-Hf geochronology of calcite(Copernicus Publications on behalf of the European Geosciences Union, 2022) Simpson, A.; Glorie, S.; Hand, M.; Spandler, C.; Gilbert, S.; Cave, B.The ability to constrain the age of calcite formation is of great utility to the Earth science community, due to the ubiquity of calcite across a wide spectrum of geological systems. Here, we present the first in situ laser ablation inductively coupled tandem quadrupole mass spectrometry (LA-ICP-MS/MS) Lu–Hf ages for calcite, demonstrating geologically meaningful ages for iron oxide copper gold (IOCG) and skarn mineralisation, carbonatite intrusion, and low-grade metamorphism. The analysed samples range in age between ca. 0.9 and ca. 2 Ga with uncertainties between 1.7 % and 0.6 % obtained from calcite with Lu concentrations as low as ca. 0.5 ppm. The Lu–Hf system in calcite appears to be able to preserve primary precipitation ages over a significant amount of geological time, although further research is required to constrain the closure temperature. The in situ approach allows calcite to be rapidly dated while maintaining its petrogenetic context with mineralisation and other associated mineral processes. Therefore, LA-ICP-MS/MS Lu–Hf dating of calcite can be used to resolve the timing of complex mineral paragenetic sequences that are a feature of many ancient rock systems.Item Metadata only Thermal history of the East Antarctic margin: Campaign-style apatite U-Pb and fission track study(THERMO, 2023) Mayer-Ullmann, F.; Glorie, S.; Mulder, J.; Hand, M.; Morrissey, L.; Verhaert, S.; Halpin, J.; 18th International Conference on Thermochronology (Thermo) (3 Sep 2023 - 8 Sep 2023 : Riva del Garda, Italy)Item Metadata only Apatite laser-ablation Lu-Hf - U-Pb tandem thermochronology: a novel method to constrain high temperature thermal histories(THERMO, 2023) Glorie, S.; Kharkongor, M.; Bedoya Mejia, A.; Hand, M.; Simpson, A.; Nixon, A.; Kirkland, C.; Chew, D.; 18th International Conference on Thermochronology (Thermo) (3 Sep 2023 - 8 Sep 2023 : Riva del Garda, Italy)Item Open Access A grain-by-grain comparison of apatite fission-track analysis by LA-ICP-MS and the External Detector Method(Elsevier BV, 2023) Seiler, C.; Boone, S.C.; Kohn, B.P.; Gleadow, A.J.W.Laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is increasingly used in fission-track analysis to determine the uranium content of host mineral specimens, particularly apatite. Fission-track dating by LA-ICP-MS (LAFT) has several advantages over the conventional External Detector Method (EDM), particularly in terms of sample turn-around times and the fact that neutron irradiations and the handling of radioactive materials are no longer necessary, while providing a similar level of in-situ information about parent nuclide ( 238U) concentrations. In addition, it facilitates the simultaneous measurement of multiple isotopes for double or triple-dating approaches or compositional characterisation. While it is often implicitly assumed that the EDM and LAFT fission-track dating approaches produce equivalent results, this assertion has yet to be adequately tested. We present an extensive dataset of apatite fission track results from 17 samples representing a large range of fission-track ages (~0–2 Ga), 238U concentrations (0.14–410 ppm) and thermal histories that were analysed grain-by-grain using both techniques in order to investigate whether they yield concordant results during routine fission-track analysis. Apart from a few outliers, our data show that 238U concentrations measured by the EDM and LAFT techniques yield indistinguishable results across at least three orders of magnitude when a similar calibration system against rapidly cooled standards (e.g., Durango) is used. Comparison of single grain pooled and central ages reveals that LAFT ages are within error of EDM ages for apatite fission track standards such as Fish Canyon Tuff or Durango, as well as for a range of other samples whose shorter mean confined track lengths (<13 μm) and broader track distributions indicate they experienced more complex cooling histories. The most important conclusion here is that both the conventional EDM and LAFT methods can be expected to yield identical results for the breadth of ages, 238U concentrations, and underlying thermal histories commonly found in real world apatites. Importantly, the aggregate empirical calibrations for EDM and LAFT mask an underlying assumption that the mean etchable range of fission fragments is a constant having the mean value observed for spontaneous tracks in age standards such as the Durango apatite. Given that this assumption is known to be false in the great majority of samples, it is our view that empirically derived EDM and LAFT fission-track ages are best considered as model ages and that there should be greater clarity about the assumptions involved in their calculation.Item Metadata only Quaternary plant macrofossils from Robertson Cave, Naracoorte, South Australia: reproductive structures(Taylor & Francis, 2023) Atkins, R.; Hill, R.; Hill, K.; Munroe, S.; Reed, E.The World Heritage Naracoorte Caves in southeastern South Australia are important palaeontological sites known primarily for their diverse vertebrate fossils. Some of the caves also contain well-pre- served Quaternary plant macrofossils, but little palaeobotanical research has been undertaken to date. Here, we describe the angiosperm plant taxa represented by macrofossils of reproductive struc- tures that have been extracted from the Robertson Cave sediment deposit; this has an age range of 820–24,230 years BP. We identified 29 angiosperm taxa representing 20 families. These represent some of the plant species that grew in the Naracoorte region during the Quaternary, and form a database for future plant identification and palaeovegetation reconstructions.Item Open Access Detrital garnet geochronology by in-situ U-Pb and Lu-Hf analysis: A case study from the European Alps(American Geophysical Union, 2023) Mark, C.; O’Sullivan, G.; Glorie, S.; Simpson, A.; Andò, S.; Barbarano, M.; Stutenbecker, L.; Daly, J.S.; Gilbert, S.Detrital geochronology employing the widely-used zircon U-Pb proxy is biased towards igneous events and metamorphic anataxis; additionally, zircon is highly refractory and frequently polycyclic. Garnet, a rock-forming and thus commonly-occuring mineral, is predominantly metamorphic and much less refractory. Here, we report in-situ U-Pb and Lu-Hf ages from detrital garnet hosted in ancient and modern sediments of the European Alps. Both geochronometers are biased towards the most recent garnet-crystallising metamorphic event in the source area, with fewer inherited ages. This likely reflects efficient removal of inherited garnet during diagenesis and metamorphism, and is in contrast to detrital zircon, apatite, and rutile U-Pb data which largely record pre-Alpine ages. Neither the U-Pb nor Lu-Hf system in garnet exhibits a relationship between age recovery and composition. However, the Lu-Hf system in garnet yields significantly better age recovery than the U-Pb system. Estimated initial ²³⁸U/²⁰⁶Pbc values at the time of crystallization are near unity for the garnet analysed in this study, suggesting that garnet does not significantly partition U from Pb during crystallization, at least for the generally almandine-rich garnets analysed in this study. Hence, Lu-Hf geochronology of detrital garnet offers an effective method to detect and date the most recent phase of mid-grade metamorphism in sub-anatectic source areas, in which detrital zircon U-Pb analysis may be of less utility.Item Open Access Linking the Gawler Craton and Mount Isa Province through hydrothermal systems in the Peake and Denison Domain, northeastern Gawler Craton(Elsevier BV, 2023) Bockmann, M.J.; Payne, J.L.; Hand, M.; Morrissey, L.J.; Belperio, A.P.Tectonic reconstructions of Proterozoic Australia commonly place the Peake and Denison Domain of the northeastern Gawler Craton at the interface between the North and South Australian cratons prior to the reconfiguration of Australia’s main tectonic components in the Mesoproterozoic. However, this reconstruction is largely based on palaeomagnetic data as the geological correlations between these regions are currently limited, particularly during the Mesoproterozoic. The early Mesoproterozoic period is significant as it corresponds to major IOCG mineralization in the eastern Gawler Craton between 1600 Ma and 1575 Ma, and IOCG mineralization in the Mount Isa Province largely between 1550 Ma and 1490 Ma. Therefore, determining the relationship of the Peake and Denison Domain to the Gawler Craton and Mount Isa Province during this period is essential to evaluating mineral prospectivity in the northeastern Gawler Craton. New U–Pb LA-ICP-MS geochronology on zircon and titanite improves our understanding of the tectonothermal and hydrothermal history the Peake and Denison Domain during the latePalaeoproterozoic, early-Mesoproterozoic and the Cambrian–Ordovician periods. Titanite formed within largely calc-silicate alteration assemblages indicates the Peake and Denison Domain has a protracted history of hydrothermal activity, recording events at c. 1565 Ma, 1530–1515 Ma, c. 1500 Ma, c. 1465 Ma and c. 490 Ma. The highly calcic nature of the c. 1565–1500 Ma alteration in the Peake and Denison Domain shares strong similarities in age and character to the regional calcic-sodic alteration recorded in the Mount Isa Province. We suggest the two regions were influenced by similar hydrothermal systems during the early Mesoproterozoic, supporting reconstruction models that place the Peake and Denison Domain near the Mount Isa Province during the early-Mesoproterozoic. This highlights the prospectivity of the Peake and Denison Domain for Isan-style IOCG mineralization, but requires consideration of the post-1500 Ma rotation of prospective structures.Item Open Access The unroofing of Archean crustal domes as recorded by detrital zircon and apatite(Elsevier BV, 2023) Clarke, A.J.I.; Kirkland, C.L.; Glorie, S.; Gillespie, J.; Kinny, P.D.This study presents in-situ U–Pb, Lu–Hf, and Sm–Nd isotopic data for detrital zircon and apatite collected from ephemeral streams of the East Pilbara Terrane, Western Australia. Given their disparate abundances in felsic versus mafic lithologies, a tandem apatite-zircon approach may offer more holistic insights into crust formation. Apatite U–Pb data define a single age peak at c. 2.9 Ga, consistent with labile, proximal, and first-cycle detritus from the Pilbara Craton. Conversely, zircon, a more refractory and durable mineral, records a more diverse geological history with U–Pb ages spanning from 3.6 to 0.2 Ga. The apatite age of c. 2.9 Ga records the timing through the Pb closure temperature during regional cooling following prograde metamorphism, while the Lu–Hf and Sm–Nd isotopic systems in the same grains yield c. 3.2 Ga isochrons, consistent with magmatic crystallisation at that time. Crystallisation age, initial ¹⁴³Nd/¹⁴⁴Nd and trace element geochemistry (Eu/Eu*) imply a chondritic or mixed (more radiogenic plus a less radiogenic) source for the apatite grains locally derived from the East Pilbara Terrane. Conversely, zircon ɛHf data reveal a broadly chondritic Paleoarchean proto-crust undergoing continual isotopic evolution punctuated by the input of juvenile, more radiogenic material on a quasiperiodic basis. Previous workers have invoked a crust-mantle overturn model triggered by stagnant-lid cooling and the episodic (re)fertilisation of the upper mantle to account for the periodic nature of crust formation in the East Pilbara Terrane. Detrital zircon grains track this process from a c. 3.8 Ga component that may have acted as a nucleus for subsequent crust formation. The oldest detrital zircon, on average, encompass less radiogenic (−ve ɛHf) components suggesting that the oldest grains preserve the unroofing of an ancient reworked crustal nucleus. Thus, the detrital zircon load arguably provides a more holistic record of the older crust in the region than the crystalline domes alone. Specifically, the less radiogenic dome cores are preferentially eroded due to their structural position and their mineral cargo lost into the detrital archive. We demonstrate that the apatite-zircon approach can be limited by the ability of apatite to be retained through crustal denudation.Item Metadata only Laser ablation Lu-Hf geochronology of mafic igneous apatite and detrital apatite(European Association of Geochemistry and the Geochemical Society, 2023) Kharkongor, M.; Glorie, S.; Mulder, J.A.; Kirkland, C.; Chew, D.; Kohn, B.; Goldschmidt 2023 (9 Jul 2023 - 14 Jul 2023 : Lyon, France)Item Metadata only New developments in laser ablation Lu-Hf geochronology(European Association of Geochemistry and the Geochemical Society, 2023) Glorie, S.; Simpson, A.; Gilbert, S.; Hand, M.; Mulder, J.A.; Muller, A.; Goldschmidt 2023 (9 Jul 2023 - 14 Jul 2023 : Lyon, France)Item Open Access Apatite laser ablation Lu-Hf geochronology: A new tool to date mafic rocks(Elsevier, 2023) Kharkongor, M.B.K.; Glorie, S.; Mulder, J.; Kirkland, C.L.; Chew, D.; Kohn, B.; Simpson, A.Mafic rocks are the most common type of igneous rocks on Earth, however, constraining the crystallization age of mafic rocks can be challenging. Apatite is a common accessory phase in mafic rocks and is amenable to dating using the U–Pb system. However, the U–Pb system in apatite has a relatively low closure temperature (~350◦- 550 ◦C) and is therefore prone to resetting by later thermal and metasomatic events. Here, a recently developed Lu–Hf dating method using laser ablation reaction-cell mass spectrometry is applied to apatite from mafic rocks. The Lu–Hf system in apatite has a higher closure temperature (~650◦-750 ◦C) compared to U–Pb, increasing the chances of obtaining primary crystallization ages. Furthermore, the laser-ablation method allows rapid data collection compared to traditional solution-based Lu–Hf dating techniques. Four study areas were selected to compare the Lu–Hf vs U–Pb systematics of apatite in mafic igneous rocks: the Paleoproterozoic Sudbury Igneous Complex (Canada), the Neoproterozoic Borborema Province (NE Brazil), the Paleoproterozoic Fennoscandian Shield (Finland), the Archean Yilgarn Craton and adjacent Mesoproterozoic Albany Fraser Orogen (Western Australia). For all analyzed samples that have apatite trace element compositions typical of an undisturbed primary mafic igneous lithology, the Lu–Hf system retains primary igneous apatite crystallization ages, whereas the U–Pb system in the same grains often records isotopic disturbance or a cooling age. In few cases, the Lu–Hf system has also been disturbed in response to recrystallization, however, such disturbance is readily detected e potential of laser ablation apatite Lu–Hf dating to primary crystallization ages for otherwise difficult to date mafic rocks.Item Open Access One billion years of tectonism at the Paleoproterozoic interface of North and South Australia(Elsevier BV, 2023) Morrissey, L.J.; Payne, J.L.; Hand, M.; Clark, C.; Janicki, M.The Mount Woods Domain, in the northeastern Gawler Craton, occupies a tectonically important location in Proterozoic Australia, yet there is very little published U–Pb geochronology data from this region to underpin tectonic models. New LA-ICP-MS U–Pb monazite and detrital zircon geochronology reveal Archean to Paleoproterozoic basement in the central Mount Woods Domain, comprising metasedimentary rocks and garnet-bearing granite with protolith ages of c. 2550–2400 Ma and metasedimentary rocks deposited after c. 1855 Ma. The southern Mount Woods Domain contains younger metasedimentary sequences deposited after 1750 Ma. Metamorphic monazite and zircon geochronology combined with phase equilibria modelling show the rocks of the central Mount Woods Domain were metamorphosed to granulite facies between 1700 and 1670 Ma, reaching pressure and temperature conditions of 4.8–5.3 kbar and 800–840 ◦C. Monazite geochronology from samples located along major shear zones and in the westernmost Mount Woods Domain record amphibolite facies metamorphism and reworking at 1570–1550 Ma, with a further phase of shear zone activity along the northern margin of the Mount Woods Domain at c. 1480 Ma. Laser ablation inductively coupled plasma triple quadrupole mass spectrometry (LA-ICP-QQQ-MS) Rb–Sr biotite ages from across the Mount Woods Domain range between 1480 and 1390 Ma. The protracted geological history in the Mount Woods Domain from c. 2500–1400 Ma provides a piercing point linking different regions of Proterozoic Australia and western Laurentia during the tenure of the Nuna supercontinent.Item Metadata only Isotopic modelling of Archean crustal evolution from comagmatic zircon-apatite pairs(Elsevier BV, 2021) Gillespie, J.; Kinny, P.D.; Kirkland, C.L.; Martin, L.; Nemchin, A.A.; Cavosie, A.J.; Hasterok, D.The composition of Earth's early crust is challenging to assess as only a fragmented record remains. As a consequence, deciphering the composition of early crust as a means to understand early processes on our planet often relies on the isotopic composition of resistive minerals. Here we present a new tool for investigating igneous petrogenesis and crustal evolution by combining 87Sr/86Sr measurements of apatite inclusions with U–Pb and Hf isotope analysis of their host zircon crystals. This approach takes advantage of the complementary inverse fractionation behaviour of Rb/Sr and Lu/Hf, and the cogenetic host/inclusion relationship, to link the three isotopic systems and construct an evolution model in triple isotope space. By applying this triple isotope system modelling to Mesoarchean igneous rocks from the Akia terrane in SW Greenland, we reconstruct a bulk SiO2 composition of 63-68 wt% for the precursor source crust and infer an average crustal residence time of 300–350 Ma. Our modelling implicates involvement of intermediate to felsic Paleo-Eoarchean crust in the genesis of voluminous 3.0 Ga magmatic rocks of the Akia terrane, one of the largest components of the Archean North Atlantic Craton. A further outcome of this approach is the ability to place more robust empirical constraints on the Lu/Hf ratio of the precursor crust by comparison of the modelling output to a global whole-rock dataset. The approach in this work provides a template for further application to ancient rocks in order to better understand the evolution of early Earth.Item Open Access Hydrated komatiites as a source of water for TTG formation in the Archean(Elsevier BV, 2023) Tamblyn, R.; Hermann, J.; Hasterok, D.; Sossi, P.; Pettke, T.; Chatterjee, S.The preserved Archean continental crust is dominantly comprised of tonalite-trondhjemite-granodiorite (TTG) suites associated with less abundant low-grade greenstone belts. The exact processes that form TTGs, as well as the source rock they are derived from, are difficult to constrain from the sparse Archean geological record. However, studies show that the water-present partial melting of metamorphosed basalt at temperatures of 750–950 ◦C is required to produce large volumes of partial melt with TTG compositions. In this contribution, we investigate if hydrated komatiites — a constituent of greenstone belts — played a vital role in TTG genesis. Using petrology, mineral chemistry and phase equilibria modelling of representative komatiite samples, combined with analysis of a global geochemical dataset of komatiites and basaltic komatiites, we show that during metamorphism hydrated komatiites can release at least 6 weight % mineral-bound water. Up to 5 weight % of this water is released by breakdown of chlorite and tremolite at temperatures between 680 and 800 ◦C, regardless of the P–T path (i.e., tectonic scenario) experienced by the komatiitic rocks. As the temperatures of komatiite dehydration are above the water-saturated basalt solidus, the released water can trigger voluminous partial melting of basalt to ultimately create TTG batholiths. This considerable hydration potential of komatiites is due to their high XMg (XMg = molar Mg/[Mg+Fe]), which stabilises water-rich minerals during oceanic alteration on the seafloor, but also extends the stability of Mg-rich chlorite to high temperatures. During prograde metamorphism, the XMg, CaO and Al2O3 content of the reactive rock composition determines the proportion of chlorite vs amphibole, and therefore the volume of water which can be transported to temperatures of >750 ◦C. Despite the low abundance of komatiites in greenstone belts, they potentially played a vital role in crustal formation and the Earth’s early water cycle.Item Open Access Characterising the economic Proterozoic Glyde Package of the greater McArthur Basin, northern Australia(Elsevier BV, 2023) Subarkah, D.; Collins, A.S.; Farkaš, J.; Blades, M.L.; Gilbert, S.E.; Jarrett, A.J.M.; Bullen, M.M.; Giuliano, W.The greater McArthur Basin is an informal term for a Palaeo-to-Mesoproterozoic sedimentary system that consists of terranes from the McArthur Basin, Birrindudu Basin, and the Tomkinson Province. These spatially distant basins are interpreted to connect in the subsurface based on geophysical, lithological, and geochronological evidence. The coeval sedimentary units of the greater McArthur Basin were subdivided into non-genetic depositional ‘packages’ bookended by regional unconformities. In ascending order, these packages are the: Redbank, Goyder, Glyde, Favenc, and Wilton Packages. The ca. 1660–1610 Ma Glyde Package is the focus of this study and includes the economically important Barney Creek Formation, found in the McArthur Basin sensu stricto. The Barney Creek Formation hosts the world-class, sediment-hosted, Zn-Pb-Ag McArthur River deposit. Importantly, it is also a key petroleum source rock and unconventional hydrocarbon reservoir, containing Australia’s geologically oldest oil and gas discoveries and forming a part of the McArthur Petroleum Supersystem. Consequently, identifying chronostratigraphically similar units elsewhere in the greater McArthur Basin is important for explorers in finding analogous economic resources. In situ Rb–Sr geochronological results of the Barney Creek Formation shales sourced from borehole LV09001 yielded ages of 1634 ± 59 Ma and 1635 ± 67 Ma. Shale samples from Fraynes Formation in borehole Manbulloo S1 were dated at 1630 ± 57 Ma and 1636 ± 42 Ma using the same approach. These ages are in good agreement with U–Pb ages of tuffaceous layers from the same units, suggesting that they represent their early burial histories and not secondary, post-depositional events. These results indicate that the Fraynes Formation and the Barney Creek Formation are direct chronostratigraphic equivalents, with ages within analytical error of each other. In addition to the geochronological similarities, the δ13Ccarb, 87Sr/86Sr, and δ88/86Sr isotopic constraints from both units also display parallel geochemical fingerprints up-section. These include a positive δ13Ccarb excursion of ∼2.0 ‰, a trend towards more crustal-dominated 87Sr/86Sr ratios, and a negative δ88/86Sr excursion of ∼-0.25 ‰. These findings further support the application of isotopic chemostratigraphy as a powerful tool to correlate distal carbonaceous rocks in the basin system. Importantly, these geochemical fingerprints also show that the McArthur Group and the Limbunya Group experienced similar changes in palaeoenvironments during the evolution of the basin system. However, trace element data collated in this study indicates that they may have recorded different, heterogeneous palaeoredox histories. Geochemical models based on redox-sensitive trace elements V and Mo suggest that the Fraynes Formation sustained a much more euxinic water column as opposed to the Barney Creek Formation. These differences may have implications for the accumulation and preservation of base metals and hydrocarbons within the sediment.Item Open Access A geospatial platform for the tectonic interpretation of low-temperature thermochronology Big Data(Nature Publishing Group, 2023) Boone, S.C.; Kohlmann, F.; Noble, W.; Theile, M.; Beucher, R.; Kohn, B.; Glorie, S.; Danišík, M.; Zhou, R.; McMillan, M.; Nixon, A.; Gleadow, A.; Qin, X.; Müller, D.; McInnes, B.Low-temperature thermochronology is a powerful tool for constraining the thermal evolution of rocks and minerals in relation to a breadth of tectonic, geodynamic, landscape evolution, and natural resource formation processes through deep time. However, complexities inherent to these analytical techniques can make interpreting the significance of results challenging, requiring them to be placed in their geological context in 4-dimensions (3D + time). We present a novel tool for the geospatial archival, analysis and dissemination of fission-track and (U-Th)/He data, built as an extension to the open-access AusGeochem platform (https://ausgeochem.auscope.org.au) and freely accessible to scientists from around the world. To demonstrate the power of the platform, three regional datasets from Kenya, Australia and the Red Sea are placed in their 4D geological, geochemical, and geographic contexts, revealing insights into the tectono-thermal evolutions of these areas. Beyond facilitating data interpretation, the archival of fission track and (U-Th)/He (meta-)data in relational schemas unlocks future potential for greater integration of thermochronology and numerical geoscience techniques. The power of formatting data to interface with external tools is demonstrated through the integration of GPlates Web Service with AusGeochem, enabling thermochronology data to be readily viewed in their paleogeographic context through deep time from within the platform.Item Open Access Laser ablation (in situ) Lu-Hf dating of magmatic fluorite and hydrothermal fluorite-bearing veins(Elsevier, 2023) Glorie, S.; Mulder, J.; Hand, M.; Fabris, A.; Simpson, A.; Gilbert, S.Fluorite (CaF2) is a common hydrothermal mineral, which precipitates from fluorine-rich fluids with an exceptional capacity to transport metals and Rare Earth Elements (REEs). Hence, the ability to date fluorite has important implications for understanding the timing of metal transport in hydrothermal systems. Here we present, for the first time, fluorite Lu-Hf dates from fluorite-carbonate veins from the Olympic Cu-Au Province in South Australia. The fluorite dates were obtained in situ using the recently developed LA-ICP-MS/MS Lu-Hf dating method. A fluorite-calcite age of 1588 ± 19 Ma was obtained for the Torrens Dam prospect, consistent with the timing of the formation of the nearby Olympic Dam iron-oxide copper gold Breccia Complex. Veins in the overlying Neoproterozoic successions were dated at 502 ± 14 Ma, indicating a temporal link between Cu-sulphide remobilisation and the Delamerian Orogeny. Additionally, we present a multi-session reproducible date for magmatic fluorite from a monzogranite in the Pilbara Craton (Lu-Hf age of 2866 ± 19 Ma). This age is consistent with a garnet Lu-Hf age from the same sample (2850 ± 12 Ma) and holds potential to be developed into secondary reference material for future fluorite Lu-Hf dating.Item Metadata only Orogens and detritus: unravelling the Mesoproterozoic tectonic geography of northern Australia through coupled detrital thermo- and geo-chronometers(Taylor & Francis, 2023) Yang, B.; Collins, A.S.; Blades, M.L.; Jourdan, F.This study presents detrital muscovite 40Ar/39Ar data from the Mesoproterozoic Roper Group and overlying informally named successions, in the Beetaloo Sub-basin, northern Australia. Detrital muscovite chronology reveals tectono-thermal processes within source regions and provides new constraints on the basin provenance, revising previous interpretations based on detrital zircon data. Detrital thermo- and geochronology, together demonstrate three main periods when the basin paleogeography was altered that correspond to the evolving tectonic history of the North Australia Craton (NAC) through the Mesoproterozoic. The first is characterised by an increased sediment contribution from source regions that lay along the eastern margin of Proterozoic Australia. These source regions are interpreted to have formed the uplifted rift-shoulders between Proterozoic Australia and Laurentia at ca 1.45 Ga. After that, sediments derived from eastern Proterozoic Australia sources become less voluminous up-section. The youngest analysed formation from the Roper Group, the Kyalla Formation, was predominately from sources to the south of the basin, representing another modification of basin geography. This is interpreted to result from the closure/subduction of the Mirning Ocean as the West Australian Craton (WAC) approached and collided with the NAC, resulting in an uplift of the southern margin of the NAC, at ca 1.35–1.31 Ga. The uppermost Mesoproterozoic to lower Neoproterozoic sandstone successions that overlie the Roper Group were derived from the Musgrave Province. Coupled detrital zircon and muscovite data imply a rapid cooling at ca 1.20–1.15 Ga that is interpreted to reflect syn-orogenic exhumation during the Musgrave Orogeny. Furthermore, data from the Beetaloo Sub-basin suggest that the changed basin tectonic settings reshaped basin geography and result in distinctive detrital zircon and muscovite geochronology records. In this study, we used the detrital U–Pb zircon and muscovite 40Ar/39Ar age data from the Beetaloo Sub-basin and a range of other basins deposited in different tectonic environments, including the convergent, collisional and extensional settings, to reconstruct the basin tectonic geography and illustrate various tectonic controls on basin formation in different tectonic backgrounds.