Multibeam sonar swath-mapping has revealed small submarine volcanic cones on the northeastern Lord Howe Rise (LHR), a submerged ribbon continent. Two such cones, aligned NNW and 120 km apart, were dredged at 23-24Degrees S. Water depth is about 1150 m nearby: the southern cone rises to 750 m and the northern to 900 m. Volcanic rocks dredged from the cones are predominantly highly altered hyaloclastites with minor basalt. The clasts are mostly intensely altered vesicular brownish glass with lesser basalt, in zeolitic, clayey, micritic or ferruginous cement. Lavas and hyaloclastites contain altered phenocrysts of olivine and plagioclase, and fresh clinopyroxene. The latter have compositions between acmite and Ti-augite, and match well clinopyroxene phenocrysts in undersaturated intraplate basanitic mafic lavas. Interbedded micrites in the volcaniclastics represent calcareous ooze that was deposited with (or later than) the volcanic pile. Foraminifera indicate that the oldest micrite is late Early Miocene (~16 Ma), and that the original ooze was deposited in cool water. Late Miocene to Pliocene micrites, presumed to be later infillings, all contain warm water forms. This evidence strongly suggests that both cones formed in pelagic depths in the Early Miocene. Ferromanganese crusts from the two cones are up to 7 cm thick and similar physically, but different chemically. The average growth rate is 3 mm/m.y.. Copper, nickel and cobalt content are relatively high in the north, but copper does not exceed 0.08 wt %, nickel 0.65% and cobalt 0.25%. The Mn:Fe ratio is high in the south (average 13.7) suggesting strong hydrothermal influence. Such small volcanic cones related to intraplate hotspot-type magmatism may occur in extensive fields like those off southern Tasmania. On Lord Howe Rise, the known small volcanic cones coincide with broad gravity highs in areas of shallow continental basement. The highs probably represent Neogene plume-related magmatism. The thick continental crust may dissipate and spread the magma widely, whereas plumes may penetrate thin oceanic crust more readily and build larger edifices. The correspondence of the ages derived from micropalaeontology and from extrapolating from nearby dated hotspot traces support such a genesis. Accordingly, gravity highs in the right setting may help predict fields of small volcanic seamounts.

Product no longer exists, please refer to GeoCat #30413 for the data

This dataset is a polygon theme of vegetation types or structures of the Cocos (Keeling) Islands. It is derived from topography data (possibly 1:1000 scale) created by AUSLIG. The attributes are probably meaningless. Re-coding according to actual vegetation types is recommended if this layer is to be used for analysis. The vegetation appears to match the 1987 orthophotography, and would therefore be out of date in some areas (the 1992 planning data documentation reveals that areas have been cleared since the 1987 air photos). Coverage is over West and Home Islands.

This dataset maps the geomorphic habitat environments (facies) for 213 Queensland coastal waterways. This version of the dataset includes 73 newly mapped estuaries, classified as 'Near pristine'. The classification system contains 12 easily identifiable and representative environments: Barrier/back-barrier, Bedrock, Central Basin, Channel, Coral, Flood- and Ebb-tide Delta, Fluvial (bay-head) Delta, Intertidal Flats, Mangrove, Rocky Reef, Saltmarsh/Saltflat, Tidal Sand Banks (and Unassigned). These types represent habitats found across all coastal systems in Australia. Southern and central Great Barrier Reef lagoon coasts have a broad spectrum of river, tide and wave- dominated estuaries.

This dataset contains points, lines and polygon data of topographical, cultural and infrastructual features. A sample of the Arc View legend that accompanies the above view can be seen here. This dataset covers all of Home Island and most of West Island however the detail is lost outside of the built up areas. The other islands and North Keeling Atoll are not included in this dataset.

Kakadu_2004_ortho_DEM

Gibson G. M., Henson P., Barlow M. & Murphy B. 2004. Basin architecture and fault geometries in the Mount Isa Western Succession: implications for mineral exploration. North Queensland Exploration and Mining 2004; extended abstracts. Australian Institute of Geoscientists Bulletin 40, p.121-22.

Structure and mineralisation of the Menzies-Boorara Shear Zone. 17th AGC, Hobart, February 2004 (A. Morey).

The mineral potential of major fault systems: a case study from NE QLD, Australia. SEG 2004 Meeting, Perth, September 2004 (I. Vos).

Mt Isa SHRIMP U-Pb analysis, Mt Isa I-New workshop, Townsville, December 2004.