A. J. Stewart

Camden and Campbelltown Hospitals

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Co-Authors

James A. Deckelman

ConocoPhillips (United States)

R. D. Shaw

Geological Survey of Western Australia

Robert Q. Oaks

Utah State University

L. P. Black

Geoscience Australia

K. T. Conrad

D. H. Blake

Umvoto Africa

D M Hoatson

Geoscience Australia

Francis A. Macdonald

University of California, Santa Barbara

I. P. Sweet

Family Court of Australia

K. Mitchell

University of Edinburgh

Cooperative Institutions

Geoscience Australia

Mineral Resources

Geological Survey of Western Australia

Australian National University

ACT Government

Dartmouth College

Commonwealth Scientific and Industrial Research Organisation

University of California, Santa Barbara

Planetary Science Institute

University of California, Berkeley

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The Arunta Inlier: A complex ensialic mobile belt in central Australia. Part 2: Tectonic history

Australian Journal of Earth Sciences (1984)

R. D. Shaw A. J. Stewart L. P. Black

Abstract The Arunta Inlier is part of a major ensialic Proterozoic mobile belt in central Australia. It comprises three latitudinal tectonic Provinces (Northern, Central and Southern) which have markedly different lithological, metamorphic and structural histories, and are bounded by major deformed zones. Tectonic activity migrated back and forth within the Inlier, and gradually lessened in intensity and extent. Large‐scale movements were localized along the bounding deformed zones from early on. Deformation and metamorphism were concentrated in the Central Province at about 1800–1750 Ma, and then at about 1700 Ma moved to its margins. Subsequent activity at 1700–1600, 1500–1400, 1050–900 and 400–300 Ma was concentrated in the Southern Province and in a belt which extended NW across the entire Inlier from the E part of the Southern Province. The tectonic evolution of the Arunta Inlier resulted from six cycles of crustal extension and compression. The first (before 1800 Ma), and possibly the second (1800–1750 Ma) caused rifting and then limited subduction of subcrustal lithosphere. The later cycles suggest repeated thermal activity and thrust‐faulting in relatively narrow crustal belts above a long‐lasting elongate plume in the mantle. Key words: tectonicsmetamorphismA‐subductionensialic riftingPrecambrian mobile beltsArunta Inliercentral Australia

Orogeny

10.1080/08120098408729305

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Citations (141)

An interpretation of the structure of the Blatherskite Nappe, Alice springs, Northern Territory

Journal of the Geological Society of Australia (1967)

A. J. Stewart

Abstract The basal unit of the Amadeus Basin sequence is the Heavitree Quartzite, and this formation usually forms a single east‐west ridge along the northern side of the MacDonnell Ranges. However, at Alice Springs there are two such ridges. Basement rocks crop out on the northern side of each ridge, and dolomite and shale of the Bitter Springs Formation crop out on their southern sides. The northern outcrop of dolomite and shale is tightly folded, and is separated from the southern outcrop of basement by a major fault. The bedding of the sediments, the axial plane of the fold, and the fault all dip south at about 45°. Inverted facings on parasitic folds indicate that the northern outcrop of quartzite and dolomite plus shale is an antiform in inverted rocks. Hence the southern outcrop of basement and quartzite is synformal, and is interpreted as the frontal part of a fold nappe. The nappe started as a recumbent anticline whose middle limb of quartzite sheared out as the anticline travelled several kilometres southwards relative to the dolomite and shale below, which formed a tight recumbent syncline. Later monoclinal uplift of the northern half of the area tilted the nappe into its present south‐dipping attitude, thus converting the recumbent anticline into a synform and the recumbent syncline into an antiform.

Anticline

Outcrop

Syncline

Basement

10.1080/00167616708728656

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Citations (17)

Seamless chronostratigraphic solid geology of the North Australian Craton

A. J. Stewart S. F. LIU M.-A. Bonnardot L.M. Highet M. T. Woods

Geological maps are one of the most important datasets used in resource exploration and management. Despite increasing demand for subsurface resources such as minerals, groundwater and energy, maps of the inferred subsurface geology of Australia and other continents have been limited to small regions or jurisdictions. Here, we present the first seamless semi-continental chronostratigraphic solid geology dataset of the North Australian Craton. This dataset comprises five time slices of stratigraphic units: Cenozoic, Mesozoic, Paleozoic, Neoproterozoic and pre-Neoproterozoic. Interpretation of covered units is based on available data: surface geology and solid geology maps, magnetic intensity and gravity images, drilling logs, reflection seismic profiles and airborne electromagnetic soundings. In total, 2008 units have been mapped, all linked to the Australian Stratigraphic Units Database. So far, these maps have led to a refinement of sedimentary basin and tectonic province outlines, lessened the risks of mineral exploration through Australia’s extensive superficial cover, disclosed geological units known to host resources elsewhere, and highlighted undercover regions with poor geological constraints.

10.11636/134486

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Citations (2)

Amelia Creek: a Proterozoic impact structure in the Davenport Ranges, Northern Territory

Australian Journal of Earth Sciences (2005)

Francis A. Macdonald K. Mitchell A. J. Stewart

The Amelia Creek impact structure is located in Australia's Northern Territory in folded Palaeoproterozoic strata of the Davenport Ranges (20°51'S, 134°53′E). An impact origin is confirmed by presence of unequivocal shatter cones with apices that point upwards, and by planar microstructures in quartz grains from target sandstones of the Hatches Creek Group. Aeromagnetic, advanced spaceborne thermal emission and reflection radiometer (ASTER), and X-band synthetic aperture radar (X-SAR) images show an area of anomalous deformation in which smooth regional trends are disrupted by arcuate features at a 10 km radius to the north and south of the shock-metamorphosed rocks. However, no arcuate forms are apparent to the east and west of these shocked rocks, and instead, large south-southwest-trending faults are present about 6 km away on both sides. Despite pervasive shatter coning, typical of the central region of complex impact structures, no structural uplift is apparent, but instead the shocked rocks lie at the southern toe of a north-northeast-trending syncline. These shatter cones overprint and post-date the Palaeoproterozoic regional deformation, and thus, the impact structure has not been refolded and its abnormal form is likely due to pre-existing structure in the target rocks and/or an oblique impact. Small pockets of undeformed Late Neoproterozoic and Middle Cambrian strata are exposed in palaeovalleys in the central region of the structure, constraining the time of the impact to the Proterozoic.

Impact structure

Syncline

10.1080/08120090500170401

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Citations (12)

The role of thrusting in the structural development of the Mount Isa Mine and its relevance to exploration in the surrounding region; discussion

Economic Geology (1992)

A. J. Stewart

Mount

Relevance

10.2113/gsecongeo.87.6.1659

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Citations (3)

Sedimentation and tectonics in the northeastern and central Amadeus Basin, central Australia

Robert Q. Oaks James A. Deckelman K. T. Conrad Lonn P. Hamp Johnnie O. Phillips

Sedimentation

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Citations (6)

The Arunta Inlier: a complex ensialic mobile belt in central Australia. Part 1: Stratigraphy, correlations and origin

Australian Journal of Earth Sciences (1984)

A. J. Stewart R. D. Shaw L. P. Black

The Arunta Inlier is a 200 000 km2 region of mainly Precambrian metamorphosed sedimentary and igneous rock in central Australia. To the N it merges with similar rocks of lower metamorphic grade in the Tennant Creek Inlier, and to the NW it merges with schist and gneiss of The Granites‐Tanami Province. It is characterized by mafic and felsic meta‐igneous rocks, abundant silicic and aluminous metasediments and carbonate, and low‐ to medium‐pressure metamorphism. Hence, the Arunta Inlier is interpreted as a Proterozoic ensialic mobile belt floored by continental crust. The belt evolved over about 1500 Ma, and began with mafic and felsic volcanism and mafic intrusion in a latitudinal rift, followed by shale and limestone deposition, deformation, metamorphism and emergence. Flysch sedimentation and volcanism then continued in geosynclinal troughs flanking the ridge of meta‐igneous rocks, and were followed by platform deposition of thin shallow‐marine sediments, further deformation, and episodes of metamorphism and granite intrusion.

Felsic

10.1080/08120098408729304

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Citations (95)

The Proterozoic Hatches Creek Group; an ensialic sandstone-bimodal volcanic association in central Australia

D. H. Blake A. J. Stewart I. P. Sweet

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Citations (6)

Cambrian River Terraces and Ridgetops in Central Australia: Oldest Persisting Landforms?

Science (1986)

A. J. Stewart D. H. Blake C. D. Ollier

Fluvial sediments in paleovaileys cut in the Ashburton surface of the Davenport province of central Australia form terrace remnants that appear to retain their original depositional tops and have probably existed as subaerial landforms since their inception. Marine fossils in sediments conformable with the fluvial sediments near the southeast margin of the province give a Cambrian age for the terraces; the Ashburton surface forming the ridgetops between the paleovalleys is Cambrian or older.

Subaerial

Landform

Terrace (agriculture)

River terraces

Conformable matrix

Paleosol

10.1126/science.233.4765.758

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Citations (46)

Mesothrust versus megathurst interpretations of the structure of the northeastern Amadeus Basin, central Australia

A. J. Stewart Robert Q. Oaks James A. Deckelman R. D. Shaw

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