Anus cam - Define stratigraphic dating

These granulites are statically metamorphosed gabbros, preserving ghosted ophitic textures, recrystallised to granoblastic two pyroxene assemblages.

Peak metamorphic conditions of ~730 ºC at low pressures between 2.5-5.0 kbar, indicate very high average thermal gradients (G – simply the ratio T/depth assuming a density of 2.8 gm/cm3) between 45-80 ºC/km.

define stratigraphic dating-68

• Ma arc related metamorphism • M1 moderate-P metamorphism • M2 regional metamorphism • M3a rift related metamorphism • M3b late-stage alteration events (1) BROAD THERMO-BAROMETRIC EVOLUTION OF THE EASTERN GOLDFIELDS SUPERTERRANE.

Ben Goscombe Geological relationships, relative garnet Lu-Hf chronology, absolute PT calculations and spatial database of metamorphic parameters across all domains, constrain the metamorphic evolution of the Eastern Goldfields Superterrane (EGST).

Outcomes of the East Yilgarn research were published as GA Record 2009/23, with full datasets and maps.

The latest outcomes and models will be published in international journals and conferences in 2010 on release from stake-holders, see abstracts and extended abstracts reproduced below.

alternative 2) are shallow and/or slow subduction (typical subduction has G Lu-Hf garnet ages are consistent with stratigraphy; and suggest that regional metamorphic, main phase matrix parageneses in greenstones grew 17-23 Ma before assemblages within turbiditic post-volcanic late basins (PVLB).

The regional M2 thermal anomaly possibly continued over a protracted period and into continuum with the thermal event associated with M3a metamorphism of the PVLB’s.

The West Yilgarn Craton Metamorphic Project (WYCMP) will involve collaboration with: Richard Blewett (Geoscience Australia), Prof.

David Foster (University of Florida) for titanite and zircon geochronology, Dr Ben Wade (Adelaide Microscopy) for monazite geochronology and the GSWA geologists working on the Yilgarn Craton; Steve Wyche, Tim Ivanic and Sandra Romano.

(1) Either these medium-P, low-G conditions were widespread regional metamorphism and the current restricted distributions are due to late-stage exhumation bringing only a portion into the shallow crustal (i.e. This scenario is supported by exposures within shear zones but nevertheless would predict more widespread relict medium-P parageneses, such as in garnet cores, boudins and xenoliths.

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