scholarly journals A Globally Significant Potential Megascale Geopark: The Eastern Australian Mantle Hotspot Interacting with a North-Migrating Heterogeneous Continental Plate Creating a Variety of Volcano Types, Magmas, Xenoliths, and Xenocrysts

2021 ◽  
Author(s):  
Vic Semeniuk ◽  
Margaret Brocx
Keyword(s):  
Sedimentary Basins ◽  
Eurasian Plate ◽  
Volcanic System ◽  
Compositional Evolution ◽  
Continental Plate ◽  
Volcanic Chain ◽  
Eastern Australia ◽  
Fold Belts ◽  
Metamorphic Terranes ◽  
Host Rocks

Australia commenced separating from Antarctica some 85 million years ago, finally separating about 33 million years ago, and has been migrating northwards towards the Eurasian plate during that time. In the process, Australia, on its eastern side, progressively passed over a mantle hotspot. A magma plume intersected a variable lithocrust with various lithologic packages such as Phanerozoic sedimentary basins, fold belts and metamorphic terranes, and Precambrian rocks. As such, there was scope for compositional evolution of magmas through melting and assimilation, as well as plucking of host rocks to include xenoliths, and xenocrysts. The volcanic chain, volcanoes, and lava fields that are spread latitudinally along 2000 km of eastern Australia present a globally-significant volcanic system that provides insights into magma and crust interactions, into the variability of xenoliths and xenocrysts, into magma evolution dependent on setting, and into the mantle story of the Earth. The Cosgrove Volcano Chain is an example of this, and stands as a globally-unique potential megascale geopark.

Seismic Structure and Tectonic Evolution of Borneo and Sulawesi

2021 ◽  
Author(s):  
Harry Telajan Linang ◽  
Amy Gilligan ◽  
Jennifer Jenkins ◽  
Tim Greenfield ◽  
Felix Tongkul ◽  
...  
Keyword(s):  
Subduction Zones ◽  
Receiver Function ◽  
Leading Edge ◽  
Sedimentary Basins ◽  
Crustal Thickness ◽  
The Philippines ◽  
Seismic Structure ◽  
Eurasian Plate ◽  
Seismic Stations ◽  
Preliminary Results

<div> <div> <div> <p>Borneo is located at the centre of Southeast Asia, which is one of the most active tectonic regions on Earth due to the subduction of the Indo-Australian plate in the south and the Philippines Sea plate in the east. Borneo resides on the leading edge of the Sundaland block of the Eurasian plate and exhibits lower rates of seismicity when compared to the surrounding regions due to its intraplate setting. Sulawesi, an island which lies just southeast of Borneo, is characterised by intense seismicity due to multiple subduction zones in its vicinity. The tectonic relationship between the two islands is poorly understood, including the provenance of their respective lithospheres, which may have Eurasian and/or East Gondwana origin.</p> <p>Here, we present recent receiver function (RF) results from temporary and permanent broadband seismic stations in the region, which can be used to help improve our understanding of the crust and mantle lithosphere beneath Borneo and Sulawesi. We applied H-K stacking, receiver function migration and inversion to obtain reliable estimates of the crustal thickness beneath the seismic stations. Our preliminary results indicate that the crust beneath Sabah (in northern Borneo), which is a post-subduction setting, appears to be much more complex and is overall thicker (more than 35 km) than the rest of the island. In addition, we find that crustal thickness varies between different tectonic blocks defined from previous surface mapping, with the thinnest crust (23 to 25 km) occurring beneath Sarawak in the west-northwest as well as in the east of Kalimantan.</p> <p>We also present preliminary results from Virtual Deep Seismic Sounding (VDSS) in northern Borneo, where from the RF results we know that there is thick and complex crust. VDSS is able to produce well constrained crustal thickness results in regions where the RF analysis has difficulty recovering the Moho, likely due to complexities such as thick sedimentary basins and obducted ophiolite sequences.</p> </div> </div> </div>

scholarly journals A preserved early Ediacaran magmatic arc at the northernmost portion of the Transversal Zone central subprovince of the Borborema Province, Northeastern South America

2016 ◽  
Vol 46 (4) ◽  
pp. 491-508 ◽  
Author(s):  
Benjamim Bley de Brito Neves ◽  
◽  
Edilton José dos Santos ◽  
Reinhardt Adolfo Fuck ◽  
Lauro César Montefalco Lira Santos ◽  
...  
Keyword(s):  
Granitic Rocks ◽  
Lower Plate ◽  
Low Grade ◽  
Northeast Brazil ◽  
The South ◽  
Magmatic Arc ◽  
Continental Plate ◽  
Borborema Province ◽  
Northern Portion ◽  
Fold Belts

ABSTRACT: Magmatic arcs are an essential part of crust-forming events in planet Earth evolution. The aim of this work was to describe an early Ediacaran magmatic arc (ca. 635-580 Ma) exposed in the northernmost portion of the Transversal Zone, central subprovince of Borborema Province, northeast Brazil. Our research took advantage of several syntheses by different authors, including theses and dissertations, carried out on magmatic rocks of the study area for the last 30 years. The ca. 750 km long and up to 140 km wide arc, trending ENE-WSW, is preserved to the south of the Patos Lineament, between 35º15' and 42º30'W and 7º15' and 8ºS. About 90 different stocks and batholiths of I-type granitic rocks were mapped along this orogenic zone, preferentially intruding low-grade schists of the Cryogenian-Ediacaran Piancó-Alto Brígida (SPAB) belt. Three igneous supersuites are recognized: a) epidote-bearing granodiorites and tonalites ("Conceição" type); b) high-K calc-alkaline granites ("Itaporanga" type); c) biotite granodiorites of trondhjemite affinity ("Serrita" type). A fourth group of peralkalic and shoshonitic rocks occurs to the south of the previous ones, reflecting special tectonic conditions. NNE-SSW trending Paleoproterozoic fold belts, surrounding Archean nuclei, characterize the continental part of the northern lower plate. The oceanic fraction of this lower plate was recycled by subduction and scarce remnants of which may be seen either within the enclosing low-grade schists or as xenoliths within the arc intrusions. The upper continental plate presents WSW-ENE structural trends and is composed of Neoproterozoic fold belts and Paleoproterozoic reworked basement inliers. Available data bear clear evidence of an Ediacaran magmatic arc built at the northern portion of the Transversal Zone in the Borborema Province, northeast Brazil.

A note on Lower Jurassic magmatism in the Coastal Cordillera of Atacama, Chile

1986 ◽  
Vol 123 (6) ◽  
pp. 699-702 ◽  
Author(s):  
J. A. Naranjo ◽  
A. Puig ◽  
M. Suárez
Keyword(s):  
Genetic Relationship ◽  
Volcanic Rocks ◽  
Lower Jurassic ◽  
The West ◽  
Coastal Cordillera ◽  
Metasedimentary Rocks ◽  
Volcanic Chain ◽  
Back Arc ◽  
Host Rocks ◽  
Previous Idea

AbstractRadiometric dates on specimens of plutons of the Coastal Cordillera of Atacama span the period 300–110 Ma. A group of dates cluster around 190 Ma and evidence is presented which strongly suggests that they represent near crystallization ages. The geographic distribution of these plutons, adjacent to Liassic tuffs and lavas (Pan de Azúcar and Posada de los Hidalgo formations), suggests a genetic relationship between them, and that the plutons were the roots of the Lower Jurassic volcanic chain. The location of these granitoids to the west of the Liassic volcanic rocks, favours a previous idea that the Liassic basin extended eastwards as a back-arc or intra-arc basin. The host rocks to the Lower Jurassic plutons include Palaeozoic granitoids and metasedimentary rocks, indicating that the volcanic chain was founded on continental crust. The distance from the Liassic plutons to the present-day trench is less than 100 km, which indicates the possibility that part of the arc-trench system of that time is missing.

scholarly journals Stratigraphy of Architectural Elements of a Buried Monogenetic Volcanic System

2019 ◽  
Vol 11 (1) ◽  
pp. 581-616 ◽  
Author(s):  
Alan Bischoff ◽  
Andrew Nicol ◽  
Jim Cole ◽  
Darren Gravley
Keyword(s):  
Geothermal Energy ◽  
Sedimentary Basin ◽  
Sedimentary Basins ◽  
Volcanic Field ◽  
Plumbing System ◽  
Volcanic System ◽  
Architectural Elements ◽  
Stratigraphic Framework ◽  
Cone Type ◽  
Geological Evolution

Abstract Large volumes of magma emplaced and deposited within sedimentary basins can have an impact on the architecture and geological evolution of these basins. Over the last decade, continuous improvement in techniques such as seismic volcano-stratigraphy and 3D visualisation of igneous bodies has helped increase knowledge about the architecture of volcanic systems buried in sedimentary basins. Here, we present the complete architecture of the Maahunui Volcanic System (MVS), a middle Miocene monogenetic volcanic field now buried in the offshore Canterbury Basin, South Island of New Zealand. We show the location, geometry, size, and stratigraphic relationships between 25 main intrusive, extrusive and sedimentary architectural elements, in a comprehensive volcano-stratigraphic framework that explains the evolution of the MVS from emplacement to complete burial in the host sedimentary basin. Understanding the relationships between these diverse architectural elements allows us to reconstruct the complete architecture of the MVS, including its shallow (<3 km) plumbing system, the morphology of the volcanoes, and their impact in the host sedimentary basin during their burial. The plumbing system of the MVS comprises saucer-shaped sills, dikes and sill swarms, minor stocks and laccoliths, and pre-eruptive strata deformed by intrusions. The eruptive and associated sedimentary architectural elements define the morphology of volcanoes in the MVS, which comprise deep-water equivalents of crater and cone-type volcanoes. After volcanism ceased, the process of degradation and burial of volcanic edifices formed sedimentary architectural elements such as inter-cone plains, epiclastic plumes, and canyons. Insights from the architecture of the MVS can be used to explore for natural resources such as hydrocarbons, geothermal energy and minerals in buried and active volcanic systems elsewhere.

scholarly journals Diversity in Ruby Geochemistry and Its Inclusions: Intra- and Inter- Continental Comparisons from Myanmar and Eastern Australia

Minerals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 28 ◽  
Author(s):  
Frederick Sutherland ◽  
Khin Zaw ◽  
Sebastien Meffre ◽  
Jay Thompson ◽  
Karsten Goemann ◽  
...  
Keyword(s):  
Trace Elements ◽  
New England ◽  
Trace Element ◽  
Oxygen Isotope ◽  
New South ◽  
New South Wales ◽  
Pb Isotopes ◽  
South Wales ◽  
Eastern Australia ◽  
Fold Belts

Ruby in diverse geological settings leaves petrogenetic clues, in its zoning, inclusions, trace elements and oxygen isotope values. Rock-hosted and isolated crystals are compared from Myanmar, SE Asia, and New South Wales, East Australia. Myanmar ruby typifies metasomatized and metamorphic settings, while East Australian ruby xenocrysts are derived from basalts that tapped underlying fold belts. The respective suites include homogeneous ruby; bi-colored inner (violet blue) and outer (red) zoned ruby; ruby-sapphirine-spinel composites; pink to red grains and multi-zoned crystals of red-pink-white-violet (core to rim). Ruby ages were determined by using U-Pb isotopes in titanite inclusions (Thurein Taung; 32.4 Ma) and zircon inclusions (Mong Hsu; 23.9 Ma) and basalt dating in NSW, >60–40 Ma. Trace element oxide plots suggest marble sources for Thurein Taung and Mong Hsu ruby and ultramafic-mafic sources for Mong Hsu (dark cores). NSW rubies suggest metasomatic (Barrington Tops), ultramafic to mafic (Macquarie River) and metasomatic-magmatic (New England) sources. A previous study showed that Cr/Ga vs. Fe/(V + Ti) plots separate Mong Hsu ruby from other ruby fields, but did not test Mogok ruby. Thurein Taung ruby, tested here, plotted separately to Mong Hsu ruby. A Fe-Ga/Mg diagram splits ruby suites into various fields (Ga/Mg < 3), except for magmatic input into rare Mogok and Australian ruby (Ga/Mg > 6). The diverse results emphasize ruby’s potential for geographic typing.

Exploring New Zealand's marine territory

2011 ◽  
Vol 51 (1) ◽  
pp. 549 ◽  
Author(s):  
Chris Uruski
Keyword(s):  
New Zealand ◽  
Deep Water ◽  
Seismic Data ◽  
East Coast ◽  
Sedimentary Basins ◽  
Petroleum Exploration ◽  
Seismic Survey ◽  
Data Set ◽  
Eastern Australia ◽  
Deep Water Part

Around the end of the twentieth century, awareness grew that, in addition to the Taranaki Basin, other unexplored basins in New Zealand’s large exclusive economic zone (EEZ) and extended continental shelf (ECS) may contain petroleum. GNS Science initiated a program to assess the prospectivity of more than 1 million square kilometres of sedimentary basins in New Zealand’s marine territories. The first project in 2001 acquired, with TGS-NOPEC, a 6,200 km reconnaissance 2D seismic survey in deep-water Taranaki. This showed a large Late Cretaceous delta built out into a northwest-trending basin above a thick succession of older rocks. Many deltas around the world are petroleum provinces and the new data showed that the deep-water part of Taranaki Basin may also be prospective. Since the 2001 survey a further 9,000 km of infill 2D seismic data has been acquired and exploration continues. The New Zealand government recognised the potential of its frontier basins and, in 2005 Crown Minerals acquired a 2D survey in the East Coast Basin, North Island. This was followed by surveys in the Great South, Raukumara and Reinga basins. Petroleum Exploration Permits were awarded in most of these and licence rounds in the Northland/Reinga Basin closed recently. New data have since been acquired from the Pegasus, Great South and Canterbury basins. The New Zealand government, through Crown Minerals, funds all or part of a survey. GNS Science interprets the new data set and the data along with reports are packaged for free dissemination prior to a licensing round. The strategy has worked well, as indicated by the entry of ExxonMobil, OMV and Petrobras into New Zealand. Anadarko, another new entry, farmed into the previously licensed Canterbury and deep-water Taranaki basins. One of the main results of the surveys has been to show that geology and prospectivity of New Zealand’s frontier basins may be similar to eastern Australia, as older apparently unmetamophosed successions are preserved. By extrapolating from the results in the Taranaki Basin, ultimate prospectivity is likely to be a resource of some tens of billions of barrels of oil equivalent. New Zealand’s largely submerged continent may yield continent-sized resources.

scholarly journals Mechanisms of overburden deformation associated with the emplacement of the Tulipan sill, mid-Norwegian margin

2017 ◽  
Vol 5 (3) ◽  
pp. SK23-SK38 ◽  
Author(s):  
Tobias Schmiedel ◽  
Sigurd Kjoberg ◽  
Sverre Planke ◽  
Craig Magee ◽  
Olivier Galland ◽  
...  
Keyword(s):  
Host Rock ◽  
Shear Failure ◽  
Sedimentary Basins ◽  
Rock Deformation ◽  
3D Seismic ◽  
Elastic Bending ◽  
Hydrocarbon Maturation ◽  
Dome Structure ◽  
Well Data ◽  
Host Rocks

The emplacement of igneous intrusions into sedimentary basins mechanically deforms the host rocks and causes hydrocarbon maturation. Existing models of host-rock deformation are investigated using high-quality 3D seismic and industry well data in the western Møre Basin offshore mid-Norway. The models include synemplacement (e.g., elastic bending-related active uplift and volume reduction of metamorphic aureoles) and postemplacement (e.g., differential compaction) mechanisms. We use the seismic interpretations of five horizons in the Cretaceous-Paleogene sequence (Springar, Tang, and Tare Formations) to analyze the host rock deformation induced by the emplacement of the underlying saucer-shaped Tulipan sill. The results show that the sill, emplaced between 55.8 and 54.9 Ma, is responsible for the overlying dome structure observed in the seismic data. Isochron maps of the deformed sediments, as well as deformation of the younger postemplacement sediments, document a good match between the spatial distribution of the dome and the periphery of the sill. The thickness [Formula: see text] of the Tulipan is less than 100 m, whereas the amplitude [Formula: see text] of the overlying dome ranges between 30 and 70 m. Spectral decomposition maps highlight the distribution of fractures in the upper part of the dome. These fractures are observed in between hydrothermal vent complexes in the outer parts of the dome structure. The 3D seismic horizon interpretation and volume rendering visualization of the Tulipan sill reveal fingers and an overall saucer-shaped geometry. We conclude that a combination of different mechanisms of overburden deformation, including (1) elastic bending, (2) shear failure, and (3) differential compaction, is responsible for the synemplacement formation and the postemplacement modification of the observed dome structure in the Tulipan area.

Style and intensity of late Cenozoic deformation in the Nagoorin Basin (eastern Queensland, Australia) and implications for the pattern of strain in an intraplate setting

2018 ◽  
Vol 156 (4) ◽  
pp. 605-619
Author(s):  
ABBAS BABAAHMADI ◽  
GIDEON ROSENBAUM ◽  
RENATE SLIWA ◽  
JOAN ESTERLE ◽  
MOJTABA RAJABI
Keyword(s):  
Seismic Reflection ◽  
Sedimentary Basins ◽  
Continental Margins ◽  
Plate Boundaries ◽  
Reverse Fault ◽  
Late Cenozoic ◽  
The North ◽  
Eastern Australia ◽  
Oil Shales ◽  
Far Field Stress

AbstractEastern Australia was affected by late Cenozoic intraplate deformation in response to far-field stress transmitted from the plate boundaries, but little is known about the intensity and pattern of this deformation. We used recently surveyed two-dimensional seismic reflection lines and aeromagnetic data, and data from the recently released Australian Stress Map, to investigate the structure of the Nagoorin Basin in eastern Queensland. The western margin of the Nagoorin beds was displaced by the Boynedale Fault, which is a NNW-striking SW-dipping oblique strike-slip reverse fault with a vertical throw ofc.900 m andc.16 km sinistral displacement. A significant part of this large sinistral displacement is interpreted to have occurred prior to late Cenozoic time. Several low-angle (<30°) thin-skinned thrusts with a flat-ramp geometry also displaced the Nagoorin beds, which are interpreted to have developed along detachment surfaces in oil shales and claystone. The Boynedale Fault is a segment within longer NNW-striking faults that include the North Pine and West Ipswich fault systems in eastern Queensland. These NNW-striking faults are potentially active, and may accommodate neotectonic thrust movement in response to the present-day NE–SW orientation of SHmax. Results of this study, in conjunction with previous information on sedimentary basins in eastern Australia, indicate that Cenozoic contractional deformation is stronger at the continental margins, possibly due to the presence of pre-existing rift-related structures.

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