POST-CARBONIFEROUS TECTONIC EVOLUTION OF EASTERN AUSTRALIA

1993 ◽  
Vol 33 (1) ◽  
pp. 215 ◽  
Author(s):  
L.G. Elliott
Keyword(s):  
Seismic Data ◽  
Middle Triassic ◽  
Foreland Basin ◽  
Magmatic Arc ◽  
The North ◽  
Structural Style ◽  
Tasman Sea ◽  
Eastern Australia ◽  
Sydney System ◽  
Cape York

Analysis of seismic data from the Bowen and Surat Basins has yielded valuable information on the Permian and Triassic evolution of eastern Australia. When combined with seismic data from the Clarence-Moreton and Maryborough Basins, a new understanding of the post-Triassic evolution of the region can be gained, with widespread implications for other eastern Australian basins.The Early Permian-Middle Triassic Bowen-Sydney Basin is a foreland basin system extending 2000 km in preserved section from Nowra in the south to Collinsville in the north. Permian outcrops as far north as Cape York were probably part of the same system prior to deformation and erosion. The basins in the Bowen-Sydney system were linked by similar structural and stratigraphic patterns controlled by a magmatic arc to the east. The Esk Trough and associated remnant basins east of the Taroom Trough were part of the Middle Triassic foreland sequence. The structural style in the system is dominated by thrusting from the east. An Early Triassic deformation is shown to be the most important, rather than the previously believed Middle Triassic event.The overlying Jurassic-Cretaceous foreland system, which included the Surat, Maryborough and Clarence-Moreton Basins, were once joined behind another magmatic arc, east of the Triassic arc position. A major mid-Cretaceous deformation is documented which fragmented the Jurassic-Cretaceous foreland basin into a number of remnant basins prior to the opening of the Tasman Sea in the Cenomanian. The dominant structural style is again thrusting from the east. Given the severity of the deformation, its effects are expected to be present in continental margin basins around Australia.

The Cenozoic structural evolution of the northwestern Tarim Basin, China

2021 ◽  
Author(s):  
Wenhang Liu ◽  
Piotr krzywiec ◽  
Stanisław Mazur ◽  
Fanwen Meng ◽  
Zhuxin Chen
Keyword(s):  
Tarim Basin ◽  
Late Miocene ◽  
Seismic Data ◽  
Structural Evolution ◽  
Foreland Basin ◽  
Growth Strata ◽  
The North ◽  
Kunlun Mountains ◽  
Structural Style ◽  
West Kunlun

<p>The vast Tarim basin is surrounded by Tian Shan Mountains in the north, West Kunlun Mountains in the southwest, and the Altyn Mountains in the southeast. The southwestern Tarim Basin developed within the foreland of the West Kunlun Mountains and cumulated up to 10 km of Cenozoic strata. Despite several decades of geological studies its structural styles and details of its geological evolution are still being debated. In this study, we used seven regional seismic transects from the Yecheng - Hotan area calibrated by deep wells to assess lateral variations of a structural style and syn-tectonic sedimentation in this part of the basin.</p><p>The basement of the SW Tarim Basin is covered by Paleozoic and Cenozoic strata, as revealed by several deep calibration wells. The regional north-directed basement thrust together with two evaporitic detachments including the Middle Cambrian evaporites (Awatage Formation) and Paleogene evaporites (Aertashi Formation) controlled the overall tectonic framework and structural evolution of this part of the basin. The visible growth strata on seismic data indicate progressive development of the structural wedge within the frontal W Kunlun Mountains from the Late Miocene to the Present day.</p><p>Four main Cenozoic evolutionary stages of the W Kunlun Mountains and adjacent SW Tarim Basin have been determined. At the end of Paleogene, evaporites of the Aertashi Formation have been deposited in SW Tarim Basin; their thickness, as indicated by seismic data, increases towards the Kunlun orogenic wedge which suggests their deposition within the flexural foreland basin. Then, during the Early to Middle Miocene, about 4000m of sediments have been deposited in rapidly subsiding foreland basin. Towards the end of Late Miocene-Pliocene, tectonic wedging along thrust front led to significant uplift of the Kunlun Mountains that presently form S margin of the Tarim Basin. Quaternary migration of compressional deformations towards the North, towards the basin interior led to formation of the intra-basinal Jade anticline that was re-interpreted as a thin-skinned syn-depositional “fish tail” structure detached within the Paleogene evaporites. Present-day activity along some deeply buried thrusts of the Kunlun Mts. tectonic wedge might be related to current earthquakes.</p>

Chapter 4 Paleoproterozoic (2.0–1.8 Ga) syn-orogenic sedimentation, magmatism and mineralization in the Bothnia–Skellefteå lithotectonic unit, Svecokarelian orogen

2020 ◽  
Vol 50 (1) ◽  
pp. 83-130 ◽  
Author(s):  
Pietari Skyttä ◽  
Pär Weihed ◽  
Karin Högdahl ◽  
Stefan Bergman ◽  
Michael B. Stephens
Keyword(s):  
Volcanic Rocks ◽  
Shear Zones ◽  
Low Grade ◽  
Lower Grade ◽  
Magmatic Arc ◽  
The North ◽  
Magmatic Rocks ◽  
Structural Style ◽  
Volcanogenic Massive Sulphide ◽  
Felsic Volcanic

AbstractThe Bothnia–Skellefteå lithotectonic unit is dominated by turbiditic wacke and argillite (Bothnian basin), deposited at 1.96 (or older)–1.86 Ga, metamorphosed generally under high-grade conditions and intruded by successive plutonic suites at 1.95–1.93, 1.90–1.88, 1.87–1.85 and 1.81–1.76 Ga. In the northern part, low-grade and low-strain, 1.90–1.86 Ga predominantly magmatic rocks (the Skellefte–Arvidsjaur magmatic province) are enclosed by the basinal components. Subduction-related processes in intra-arc basin and magmatic arc settings, respectively, are inferred. Changes in the metamorphic grade and the relative timing of deformation and structural style across the magmatic province are linked to major shear zones trending roughly north–south and, close to the southern margin, WNW–ESE. Zones trending WNW–ESE and ENE–WSW dominate southwards. Slip along the north–south zones in an extensional setting initiated synchronously with magmatic activity at 1.90–1.88 Ga. Tectonic inversion steered by accretion to a craton to the east, involving crustal shortening, ductile strain and crustal melting, occurred at 1.88–1.85 Ga. Deformation along shear zones under lower-grade conditions continued at c. 1.8 Ga. Felsic volcanic rocks (1.90–1.88 Ga) host exhalative and replacement-type volcanogenic massive sulphide deposits (the metallogenic Skellefte district). Other deposits include orogenic Au, particularly along the ‘gold line’ SW of this district, porphyry Cu–Au–Mo, and magmatic Ni–Cu along the ‘nickel line’ SE of the ‘gold line’.

Rift evolution and structural style in the Orphan Basin: results from regional structural restorations and crustal area balancing 

2021 ◽  
Author(s):  
Adam J. Cawood ◽  
David A. Ferrill ◽  
Alan P. Morris ◽  
David Norris ◽  
David McCallum ◽  
...  
Keyword(s):  
Cross Sections ◽  
Seismic Data ◽  
Large Scale ◽  
Structural Evolution ◽  
Strike Slip ◽  
Detachment Faults ◽  
The North ◽  
Structural Style ◽  
Complex Structural ◽  
Structural Configurations

<p>The Orphan Basin on the eastern edge of the Newfoundland continental margin formed as a Mesozoic rift basin prior to continental breakup associated with the opening of the North Atlantic. Few exploration wells exist in the basin, and until recently regional interpretations have been based on sparse seismic data coverage - because of this the structural evolution of the Orphan Basin has historically not been well understood. Key uncertainties include the timing and amount of rift-related extension, dominant extension directions, and the structural styles that accommodated progressive rift development in the basin.     </p><p>Interpretation of newly acquired modern broadband seismic data and structural restoration of three regional, WNW-ESE oriented cross-sections across the Orphan Basin and Flemish Cap provide new insights into rift evolution and structural style in the area. Our results show that major extension in the basin occurred between 167 Ma and 135 Ma, with most extension occurring prior to 151 Ma. We show that extension after 135 Ma largely occurred east of Flemish Cap due to a shift in the locus of rifting from the Orphan Basin to east of Flemish Cap. We find no evidence for discrete rifting events in the Orphan Basin, as has been suggested by other authors.  Kinematic restoration and associated heave measurements for the Orphan Basin show that extension was both widespread and relatively evenly distributed across the basin from Middle-Late Jurassic to Early Cretaceous.</p><p>We provide evidence for more widespread deposition of Jurassic strata throughout the Orphan Basin than previously interpreted, and show that Jurassic deposition was controlled by the occurrence and displacement of crustal-scale extensional detachment faults.  Structure in the three regional cross sections is dominated by large-scale, shallowly dipping extensional detachment faults. These faults mainly dip to the northwest and control the geometry and position of extensional basins – grabens and half-grabens – which occur at a range of scales. Stacked detachment surfaces, hyperextension, and attenuation of the crust are observed in central and eastern parts of the Orphan Basin. Zones of extreme crustal attenuation (to ca. 3.7 km) are interpreted to be coincident with large-displacement (up to 60 km) low-angle detachments. Results from crustal area balancing suggest that up to 41% of extension is not recognized through structural seismic interpretation, which we attribute to subseismic-scale ductile and brittle deformation, and uncertainties in the identification of detachment surfaces or complex structural configurations (e.g., overprinting of early extensional deformation).</p><p>Rifting style in the central, northern, and eastern parts of the Orphan Basin is dominated by low-angle detachment faulting with maximum extension perpendicular to the incipient rift axis. In contrast, structural geometries in the southwestern part of the basin are suggestive of transtensional deformation, and interplay of normal and strike-slip faulting.  Results from map-based interpretation show that strike-slip faults within this transtensional zone are associated with displacement transfer between half-grabens of opposing polarity, rather than regional strike-slip displacement.  These structures are interpreted as contemporaneous and kinematically linked to displacement along low-angle detachment surfaces elsewhere, and are not attributed to distinct episodes of oblique extension.       </p>

Northern Houtman Sub-basin prospectivity—preliminary results

2016 ◽  
Vol 56 (2) ◽  
pp. 577
Author(s):  
Irina Borissova ◽  
Chris Southby ◽  
George Bernardel ◽  
Jennifer Totterdell ◽  
Robbie Morris ◽  
...  
Keyword(s):  
Seismic Data ◽  
Source Rocks ◽  
Large Igneous Province ◽  
The North ◽  
Structural Style ◽  
Igneous Province ◽  
Line Spacing ◽  
History Of

In 2014–15 Geoscience Australia acquired 3,300 km of deep 2D seismic data over the northern part of the Houtman Sub-basin (Perth Basin). Prior to this survey, this area had a very sparse coverage of 2D seismic data with 50–70 km line spacing in the north and an industry grid with 20 km line spacing in the south. Initial interpretation of the available data has shown that the structural style, major sequences, and potential source rocks in this area are similar to those in the southern Houtman and Abrolhos sub-basins. The major difference between these depocentres, however, is in the volume and distribution of volcanic and intrusive igneous rocks. The northern part of the Houtman Sub-basin is adjacent to the Wallaby Plateau Large Igneous Province (LIP). The Wallaby Plateau and the Wallaby Saddle, which borders the western flank of the Houtman Sub-basin, had active volcanism from the Valanginian to at least the end of the Barremian. Volcanic successions significantly reduce the quality of seismic imaging at depth, making it difficult to ascertain the underlying thickness, geometry and structure of the sedimentary basin. The new 2D seismic dataset across the northern Houtman Sub-basin provides an opportunity for improved mapping of the structure and stratigraphy of the pre-breakup succession, assessment of petroleum prospectivity, and examination of the role of volcanism in the thermal history of this frontier basin.

Geographical distribution of living planktonic foraminifera (Protozoa) off the east coast of Australia.

1988 ◽  
Vol 39 (1) ◽  
pp. 71 ◽  
Author(s):  
S Andrijanic
Keyword(s):  
Sea Water ◽  
Planktonic Foraminifera ◽  
Distribution Patterns ◽  
Water Masses ◽  
Individual Species ◽  
The South ◽  
The North ◽  
Warm Core ◽  
Tasman Sea ◽  
Eastern Australia

Major water masses found off eastern Australia can be identified by their planktonic foraminiferal faunas. A total of 83 surface and oblique plankton samples from two cruises, in spring (October) and summer (January), between Hobart at 44� S. and Townsville at 18� S. yielded 27 species belonging to four distinct faunas: 'tropical', 'warm subtropical', 'cool subtropical' and 'transitional'. The tropical fauna is characterized by Globigerinoides sacculifer at an abundance greater than 42% and the co- dominance of Globigerinoides conglobatus, and is associated with Coral Sea water of equatorial origin. The subtropical fauna can be subdivided into warm and cool elements. The warm-subtropical fauna, with G. sacculifer more abundant than Globigerinoides ruber, inhabits Coral and Tasman Sea waters. The cool-subtropical fauna is a mixture of the warm subtropical and the transitional faunas. The transitional fauna is dominated by Globorotalia inflata and Globigerina bulloides in the south Tasman Sea subantarctic waters. It characterizes the South West Tasman water as defined by Rochford (1957). These water masses can be clearly separated, and the extent of mixing determined by their foraminiferal fauna. The shifts in the boundaries between the faunal zones was evident between spring and summer. The boundary between the tropical and subtropical water corresponds to the tropical convergence and the subtropical/transitional boundary is the Tasman Front. During the spring cruise, a warm core eddy was identified by its warm subtropical foraminiferal fauna surrounded by a transitional fauna to the south and cool subtropical fauna to the north. This water body was near 32� S., which is consistent with the reported positions of eddies shed by the East Australian Current. The distribution patterns of individual species are discussed.

MAPPING THE PLATE TECTONIC RECONSTRUCTION OF SOUTHERN AND SOUTHEASTERN AUSTRALIA AND IMPLICATIONS FOR PETROLEUM SYSTEMS

2001 ◽  
Vol 41 (1) ◽  
pp. 15 ◽  
Author(s):  
M.S. Norvick ◽  
M.A. Smith
Keyword(s):  
Second Phase ◽  
Continental Margins ◽  
Ocean Crust ◽  
Petroleum Systems ◽  
Southeastern Australia ◽  
Structural Style ◽  
Oceanic Spreading ◽  
Tasman Sea ◽  
Eastern Australia ◽  
Thermal Subsidence

Southern Australian breakup history is divisible into three phases. The first phase began with Callovian (c.159–165 Ma) rifting in the western Bight Basin. During the Tithonian (c.142–146 Ma), rifting extended eastwards into the Duntroon, Otway and Gippsland Basins. By the Valanginian (c.130–135 Ma), ocean crust formed between India and western Australia. Structural style in the western Bight changed to thermal subsidence. However, fluvio-lacustrine rift sedimentation continued in Duntroon, Otway and Gippsland until the Barremian (c.115–123 Ma) when these basins also changed to thermal subsidence. The diachronous progression of basin fill types produces a progressive shift in ages of potential source, seal and reservoir intervals along the margin.The second phase began during the Cenomanian (c.92–97.5 Ma) with uplift in eastern Australia, stress reorganisation and divergence of basin development. The Otway, Sorell and Great South Basins formed in a transtensional regime. These tectonics resulted in trap generation through faulting, inversion and wrenching. During the Santonian, oceanic spreading began in the southern Tasman Sea (c.85 Ma). Slow extension caused thinning of continental crust in the Bight and Otway Basins and subsidence into deeper water. Ocean crust formed south of the Bight Basin in the Early Campanian (c.83 Ma) and also started extending up the eastern Australian coast.The third stage in development was caused by Eocene changes to fast spreading in the Southern Ocean (c.44 Ma), final separation of Australia and Antarctica, and cessation of Tasman Sea spreading. These events caused collapse of continental margins and widespread marine transgression. The resultant loading, maturation and marine seal deposition are critical to petroleum prospectivity in the Gippsland Basin.

Late Cretaceous stratigraphy and vertebrate faunas of the Markagunt, Paunsaugunt, and Kaiparowits plateaus, southern Utah

2016 ◽  
Vol 3 ◽  
pp. 229-291 ◽  
Author(s):  
Alan L. Titus ◽  
Jeffrey G. Eaton ◽  
Joseph Sertich
Keyword(s):  
Late Cretaceous ◽  
Foreland Basin ◽  
Alluvial Plain ◽  
Terrestrial Vertebrate ◽  
The North ◽  
Single Region ◽  
The World ◽  
Kaiparowits Plateau ◽  
Fossil Preservation ◽  
Fossil Records

The Late Cretaceous succession of southern Utah was deposited in an active foreland basin circa 100 to 70 million years ago. Thick siliciclastic units represent a variety of marine, coastal, and alluvial plain environments, but are dominantly terrestrial, and also highly fossiliferous. Conditions for vertebrate fossil preservation appear to have optimized in alluvial plain settings more distant from the coast, and so in general the locus of good preservation of diverse assemblages shifts eastward through the Late Cretaceous. The Middle and Late Campanian record of the Paunsaugunt and Kaiparowits Plateau regions is especially good, exhibiting common soft tissue preservation, and comparable with that of the contemporaneous Judith River and Belly River Groups to the north. Collectively the Cenomanian through Campanian strata of southern Utah hold one of the most complete single region terrestrial vertebrate fossil records in the world.

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