U-PB-HF-O CHARACTER OF NEOARCHAEAN BASEMENT TO THE PINE CREEK OROGEN, NORTH AUSTRALIAN CRATON

Detailed field mapping between Cloncurry and Selwyn has established the existence of a common stratigraphic/tectonic history of almost all the geology east of the Overhang Shear Zone, a major suture separating the Cloncurry-Selwyn Zone from the Quamby-Malbon Belt and Mitakoodi Block. The major exception is a discrete tectonic belt in the far south of the region, the Gin Creek Block, which forms an anomalous zone of older stratigraphy and high grade metamorphism enveloped by tectonic boundaries with the surrounding units. The Cloncurry-Selwyn Zone itself could be subdivided into several sub-regions with similar internal characteristics, but for simplicity the key findings reveal that there are two principal supra-crustal packages folded and interleaved together along major faults and intruded by 1550-1510Ma granitic rocks.

Williams et al. (2009) report on new multibeam sonar bathymetry and underwater video data collected from submarine canyons and seamounts on Australia's southeast continental margin to 'investigate the degree to which geomorphic features act as surrogates for benthic megafaunal biodiversity' (p. 214). The authors describe what they view as deficiencies in the design of the Marine Protected Areas (MPAs) in the southeast region of Australia, in which geomorphology information was employed as a surrogate to infer regional-scale patterns of benthic biodiversity. This comment is designed to support and underscore the importance of evaluating MPA designs and the validity of using abiotic surrogates such as geomorphology to infer biodiversity patterns, and seeks to clarify some of the discrepancies in geomorphic terminologies and approaches used between the original study and the Williams et al. (2009) evaluation. It is our opinion that the MPA design criteria used by the Australian Government are incorrectly reported by Williams et al. (2009). In particular, we emphasise the necessity for consistent terminology and approaches when undertaking comparative analyses of geomorphic features. We show that the MPA selection criteria used by the Australian Government addressed the issues of false homogeneity described by Williams et al. (2009), but that final placement of MPAs was based on additional stakeholder considerations. Finally, we argue that although the Williams et al. (2009) study provides valuable information on biological distributions within seamounts and canyons, the hypothesis that geomorphic features (particularly seamounts and submarine canyons) are surrogates for benthic biodiversity is not tested explicitly by their study.

Pending

The Surface Hydrology Points (Regional) dataset provides a set of related features classes to be used as the basis of the production of consistent hydrological information. This dataset contains a geometric representation of major hydrographic point elements - both natural and artificial. This dataset is the best available data supplied by Jurisdictions and aggregated by Geoscience Australia it is intended for defining hydrological features.

No abstract available

33% coverage west 22-1/H52-8/15 Vertical scale: 200

G50/B1-2746-3 Vertical scale: 50

15% coverage central 22/F53/G53/8 Vertical scale: 50

22-1/H51-15/6 Vertical scale: 500