https://novaprd-lb.newcastle.edu.au/vital/access/manager/Index ${session.getAttribute("locale")} 5 Analogues to mineral sequestration of CO₂: sources of carbon in magnesite of Attunga magnesite quarry, NSW, Australia, a stable isotope study https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:12061 Sat 24 Mar 2018 10:33:05 AEDT ]]> A 53 year seasonally resolved oxygen and carbon isotope record from a modern Gibraltar speleothem: reconstructed drip water and relationship to local precipitation https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:5010 Sat 24 Mar 2018 07:44:12 AEDT ]]> Formation of the Jurassic South China large granitic province: insights from the genesis of the Jiufeng pluton https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:26786 18O=6.80/00-9.40/00) suggest that the Jiufeng pluton was mainly derived from melting of a common metasedimentary source, possibly with a minor basaltic contribution. We consider the geochemical variations of the Jiufeng pluton are primarily a result of incremental assembly of magma batches produced from rapid step-like transition from fluid-saturated to fluid-absent melting of the source. The muscovite granodiorite, with high Na₂O (>3.80wt.%; K₂O/Na₂O=~1), is interpreted to have been produced by fluid-saturated melting at low temperature (~650°C). High P₂O₅ (0.09-0.17wt.%), zircon saturation temperature (TZr=769-816°C) and La/Yb ratios (8.4-55.8) of the stage II two-mica granite support its formation from high-temperature (>800°C) biotite-dehydration melting, whereas lower P₂O₅ (<0.02wt.%), TZr (685-742°C) and La/Yb (<3) of the stage I two-mica granite suggest its generation at lower temperature, likely by muscovite-dehydration melting. We propose that extensive emplacement of basaltic melts in the lower crust most likely drove the rapid increase of mid-crustal (~20km) temperature (~50°C/m.y.) and widespread crustal melting for the formation of the Jurassic South China LGP. Therefore, formation of the LGP signifies prominent crustal growth as well as crustal reworking in an intraplate setting and was likely a response to flat-slab delamination and foundering.]]> Sat 24 Mar 2018 07:36:22 AEDT ]]> Physical conditions of gold deposition at the McPhees Deposit, Pilbara Craton, Western Australia: fluid inclusion and stable isotope constraints https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:3421 21.0 eq. wt.%, respectively). Heating experiments indicate minimum temperatures of trapping of 350 641°C for Type-I inclusions, 207 660°C for Type-II inclusions, and 143 <637°C for Type-III inclusions. Oxygen isotope compositions of quartz–actinolite and albite–actinolite pairs indicate a temperature of gold-associated alteration of ~350°C, consistent with arsenopyrite thermometry, which indicates gold mineralization at <480°C. The early CO₂-rich fluid inclusions have densities that range from 0.6 to 1.05 g/cm3 which, at 350°C, correspond to 1–2 kbar pressure, consistent with geological relations indicating that the McPhees deposit formed at <7 km. Type-I inclusions are interpreted to contain early vein-related fluids that carried gold, but this assemblage (nearly pure CO₂ and subordinate, coexisting H₂O-rich fluid inclusions) is unusual for orogenic gold deposits. It is most likely a result of fluid mixing that may have played a role in gold deposition in veins; however, host-rock lithology seems to have been a first-order control in localizing the gold.]]> Sat 24 Mar 2018 07:21:37 AEDT ]]>