In Situ U–Pb Monazite and Xenotime Geochronology of the Abra Polymetallic Deposit and Associated Sedimentary and Volcanic Rocks, Bangemall Supergroup, Western Australia

Abra is a major lead–silver–copper–gold deposit within the Bangemall Supergroup that has a total indicated and inferred resource estimate of 93 million tonnes at 4.0% lead and 10 g/t silver and 14 million tonnes at 0.6% copper and 0.5 g/t gold. The mineralization lies within the upper part of the locally defi ned Gap Well Formation, and in the lower part of the overlying West Creek Formation. These units correlate respectively with the Irregully and lower Kiangi Creek Formations of the Edmund Group.The Abra deposit is characterized by a funnel-shaped brecciated zone, interpreted as a breccia feeder-pipe, overlain by stratabound mineralization made up of the Red Zone, an underlying Black Zone, and a stringer (feeder) zone. The Red Zone is characterized by banded jaspilite, hematite, galena, pyrite, quartz, abundant barite, and siderite. The Black Zone consists of veins and rhythmically banded Pb, Zn, and minor Cu sulfi des, laminated and/or brecciated hematite, magnetite, Fe-rich carbonate, barite, and scheelite.In situ Sensitive high-resolution ion microprobe (SHRIMP) U–Pb geochronology of detrital zircon, monazite, and xenotime in sandstones from the Abra deposit yields a range of dates from c. 2450 Ma to c. 1675 Ma, consistent with results from previous detrital zircon studies. SHRIMP dating of hydrothermal monazite from the Abra deposit suggests that a mineralization event occurred at c. 1385 Ma. The presence of c. 1465 Ma metamorphic/hydrothermal monazite in sandstones from Abra indicates that the host rocks are older and therefore belong to the Edmund Group. SHRIMP geochronology of xenotime extracted from the Tangadee Rhyolite, which outcrops within the lower Kiangi Creek Formation close to the Abra deposit, yields two main age components corresponding to oscillatory-zoned cores and unzoned rims. The cores are interpreted as magmatic in origin and indicate a possible eruption age of c. 1235 Ma, whereas the rims are interpreted to record a later hydrothermal event at c. 1030 Ma. If this interpretation is correct, then the sedimentary succession containing the rhyolite is younger than the Edmund Group (1465 Ma), and may belong to the basal Collier Group (1070 Ma) although the geological setting does not support this

Enhanced Verbal Statistical Learning in Glossolalia

Glossolalia ("speaking in tongues") is a rhythmic utterance of word-like strings of sounds, regularly occurring in religious mass gatherings or various forms of private religious practices (e.g., prayer and meditation). Although specific verbal learning capacities may characterize glossolalists, empirical evidence is lacking. We administered three statistical learning tasks (artificial grammar, phoneme sequence, and visual-response sequence) to 30 glossolalists and 30 matched control volunteers. In artificial grammar, participants decide whether pseudowords and sentences follow previously acquired implicit rules or not. In sequence learning, they gradually draw out rules from repeating regularities in sequences of speech sounds or motor responses. Results revealed enhanced artificial grammar and phoneme sequence learning performances in glossolalists compared to control volunteers. There were significant positive correlations between daily glossolalia activity and artificial grammar learning. These results indicate that glossolalists exhibit enhanced abilities to extract the statistical regularities of verbal information, which may be related to their unusual language abilities

In situ U–Pb geochronology of xenotime and monazite from the Abra polymetallic deposit in the Capricorn Orogen, Australia: Dating hydrothermal mineralization and fluid flow in a long-lived crustal structure

The Proterozoic Capricorn Orogen is a major tectonic zone that records the assembly and subsequent reworking of the West Australian Craton. Recent seismic transects across the orogen have identified major crustal structures, some of which are spatially associated with hydrothermal mineral deposits. The sedimentary-rock-hosted Abra deposit, which is the largest base-metal accumulation in the Capricorn Orogen, is localized within the crust-cutting Lyons River–Quartzite Well fault zone. Robust radiometric dates for the timing of sediment deposition and hydrothermal mineralization are essential for understanding the geological history of this long-lived orogen and the processes that formed the ore deposits. In situ U–Pb SHRIMP geochronology of xenotime intergrown with magnetite–hematite–galena from the Abra ore zone yields a weighted mean 207Pb/206Pb age of 1594 ± 10 Ma (n = 14, MSWD = 2.6) which is interpreted to represent a period of xenotime growth during the hydrothermal activity responsible for the mineralization. An older coherent cluster within this group gives a weighted mean age of 1610 ± 16 Ma (n = 5, MSWD = 1.5), which constrains the depositional age of the lower Edmund Group sediments to between c. 1680 Ma (maximum age of the basal Mt Augustus Sandstone) and c. 1610 Ma. Authigenic monazite from the ore zone gives 207Pb/206Pb ages of 1375 ± 14 (n = 16, MSWD = 0.99) Ma, interpreted to represent a hydrothermal event postdating the main phase of mineralization. Monazites in samples distal to mineralization yield weighted mean 207Pb/206Pb ages of 1221 ± 14 Ma (n = 5, MSWD = 1.04) and 995 ± 18 Ma (n = 6, MSWD = 1.3), interpreted as records of discrete episodes of hydrothermal fluid flow. Our results suggest that the Lyons River–Quartzite Well Fault, which is one of the principal structures in the Capricorn Orogen, has a long history of tectonic reactivation, spanning more than 600 million years and involving crustal extension and sediment deposition, hydrothermal mineralization and multiple episodes of fluid flow. Xenotime and monazite represent ideal chronometers for investigating the complex histories of hydrothermal mineralization and fluid flow in major crustal structures, and helping to unravel the geological evolution of intracratonic orogens

Agricultural change and paddock tree loss: implications for an endangered subspecies of red-tailed black-cockatoo

Natural senescence and the intensification of agricultural practices are contributing to the continuing loss of paddock trees from agricultural regions in Australia. This is of particular concern in the southern Wimmera of western Victoria, where much of the endangered Buloke (Allocasuarina luehmannii) Woodland vegetation community is represented only by relict Buloke trees in paddocks, which also constitute critical feeding habitat for the endangered south-eastern subspecies of the Red-tailed Black-Cockatoo (Calyptorhynchus banksii graptogyne). I investigated the rate and correlates of loss of scattered Buloke trees in paddocks by examining aerial photographs taken over a period of 15 years in a region undergoing agricultural intensification. Tree loss over the period was measured using aerial photographs of five localities, covering a total of 7850 ha of agricultural land in the southern Wimmera. The average rate of loss (± 1 SE) was 25.8% ± 6.4% over the 15 years, or 1.7% per annum. The rate of tree loss was higher in areas under cultivation (32.5%) than areas under pasture (20.6%). A disproportionate number of trees was lost from locations where centre pivot irrigation systems were installed. Because of the slow growth rate of Buloke trees, revegetation efforts and offset planting are unlikely to compensate for losses of Red-tailed Black-Cockatoo habitat for approximately 100 years