EVOLUTION OF THE PERTH AND CARNARVON BASINS

1972 ◽  
Vol 12 (2) ◽  
pp. 52
Author(s):  
J.J. Veevers

Along the present southwest Australian margin, in the Perth and Carnarvon Basins, the wholly nonmarine Permian, Triassic, and Jurassic sedimentary rocks of the southern Perth Basin pass northwards into paralic and marine equivalents of the Carnarvon Basin, which additionally contains marine Silurian, Devonian, and Carboniferous rocks. These contrasts are interpreted in terms of the re-assembly of Australia in Gondwanaland: the southern Perth Basin lay alongside India in the interior of Gondwanaland, and the northern Carnarvon Basin faced a gulf of Tethys.According to this model, southwest Australia was arched in the Late Carboniferous, and the arch collapsed by rifting in the Permian, Triassic, and Jurassic, with the accumulation of thick nonmarine (in the south) to paralic and marine sediments (in the north). Rupture from India was marked by the eruption of basalt in the earliest Cretaceous, and dispersal of India and Australia was marked by rapid marginal subsidence in the Late Cretaceous. This model, derived from stratigraphical and faciological data, is supported by the ridge-and-rift structure of southwest Australia.

2018 ◽  
Vol 47 (1) ◽  
pp. 23-36
Author(s):  
Boris Valchev ◽  
Dimitar Sachkov ◽  
Sava Juranov

The Paleogene sedimentary rocks in the north-easternmost part of the territory of Bulgaria have been penetrated by numerous boreholes. In terms of regional tectonic zonation, the study area is a part of the onshore sector of the Moesian Platform, which partly includes the South Dobrogea Unit and the easternmost part of the North Bulgarian Dome with its eastern slope. The lithostratigraphy of the Paleogene successions consists of six formal units (the Komarevo, Beloslav, Dikilitash, Aladan, Avren, and Ruslar formations) and one informal unit (glauconitic marker). For compiling an overall conception of the regional aspects (lithology, thickness, spatial distribution, and relationships) of the individual lithostratigraphic units and for illustration of their spatial distribution, a 3D lithostratigraphic model based on reinterpretation of individual borehole sections has been created. The model database was compiled by integration of the original lithological data from 338 borehole sections.


1869 ◽  
Vol 6 (64) ◽  
pp. 442-446
Author(s):  
G. A. Lebour

Geology.—Stated roughly, the geology of the Department of Finistère may be said to consist of two masses of granite, one to the north and one to the south, enclosing between them nearly the whole of the sedimentary rocks of the district. These consist of Cambrian slates and gneiss, Lower, Middle, and Upper Silurian slates and grits, and very small and unimportant patches of Upper Carboniferous shales. The entire mass of these deposits has an east and west direction, and occupies the central part of the Department.


2003 ◽  
Vol 43 (1) ◽  
pp. 339 ◽  
Author(s):  
M. Partington ◽  
K. Aurisch ◽  
W. Clark ◽  
I. Newlands ◽  
S. Phelps ◽  
...  

Exploration permits WA-299-P and WA-300-P lie west of the North West Cape in a frontier part of the Carnarvon Basin where the largely Mesozoic Exmouth Sub-basin abuts against shallow Palaeozoic strata of the Gascoyne Platform. The only exploration well, within the permits, Pendock–1, penetrated a thin Valanginian Birdrong Sandstone unconformably overlying Carboniferous to Silurian units, so the Mesozoic hydrocarbon potential of the area is effectively untested.The structure of the area comprises a complex mosaic of NNE–SSW trending Early Palaeozoic extensional, listric growth faults, dissected by NW–SE trending Permian extension relay zones. Subsequent phases of Callovian– Oxfordian and Valanginian uplift, together with Late Cretaceous and Miocene inversion along the main fault zone, further complicate the structure. Several seismic events, some of which correlate with magnetic anomalies, are discordant with the local stratigraphy indicating a probable igneous origin.The primary targets are the Birdrong Sandstone and underlying Wogatti Formation, both of which host onshore oil accumulations at Rough Range and Parrot Hill–1. The retrogradational clastic shoreline facies of the Birdrong Sandstone is well known along the eastern edge of the Dampier–Barrow–Exmouth Sub-basins. The Wogatti Formation was deposited as a more restricted alluvial/ fluvial sheet sand facies, so far identified only in the onshore Cape Range area. Where the Jurassic is preserved, fluvial/alluvial channel sand facies of the Middle Jurassic Learmonth Formation, known onshore at Sandy Point–1, and Callovian nearshore sands, as observed in Unknown Hill–l, are expected to be important secondary targets.The most promising play types within the Southern Carnarvon Basin are dip and fault-dip closures at Birdrong/Wogatti level associated with Late Cretaceous reactivation of the main NE–SW listric faults, and accentuated by later Miocene compression. The most significant exploration risks are charge and the high risk of biodegradation of reservoired liquid hydrocarbons (critically linked to reservoir temperature).


1998 ◽  
Vol 135 (1) ◽  
pp. 101-119 ◽  
Author(s):  
IVAN S. ZAGORCHEV

The Paril Formation (South Pirin and Slavyanka Mountains, southwestern Bulgaria) and the Prodromos Formation (Orvilos and Menikion Mountains, northern Greece) consist of breccia and olistostrome built up predominantly of marble fragments from the Precambrian Dobrostan Marble Formation (Bulgaria) and its equivalent Bos-Dag Marble Formation (Greece). The breccia and olistostrome are interbedded with thin layers of calcarenites (with occasional marble pebbles), siltstones, sandstones and limestones. The Paril and Prodromos formations unconformably cover the Precambrian marbles, and are themselves covered unconformably by Miocene and Pliocene sediments (Nevrokop Formation). The rocks of the Paril Formation are intruded by the Palaeogene (Late Eocene–Early Oligocene) Teshovo granitoid pluton, and are deformed and preserved in the two limbs of a Palaeogene anticline cored by the Teshovo pluton (Teshovo anticline). The Palaeocene–Middle Eocene age of the formations is based on these contact relations, and on occasional finds of Tertiary pollen, as well as on correlations with similar formations of the Laki (Kroumovgrad) Group throughout the Rhodope region.The presence of Palaeogene sediments within the pre-Palaeogene Pirin–Pangaion structural zone invalidates the concept of a ‘Rhodope metamorphic core complex’ that supposedly has undergone Palaeogene amphibolite-facies regional metamorphism, and afterwards has been exhumed by rapid crustal extension in Late Oligocene–Miocene times along a regional detachment surface. Other Palaeogene formations of pre-Priabonian (Middle Eocene and/or Bartonian) or earliest Priabonian age occur at the base of the Palaeogene sections in the Mesta graben complex (Dobrinishka Formation) and the Padesh basin (Souhostrel and Komatinitsa formations). The deposition of coarse continental sediments grading into marine formations (Laki or Kroumovgrad Group) in the Rhodope region at the beginning of the Palaeogene Period marks the first intense fragmentation of the mid- to late Cretaceous orogen, in particular, of the thickened body of the Morava-Rhodope structural zone situated to the south of the Srednogorie zone. The Srednogorie zone itself was folded and uplifted in Late Cretaceous time, thus dividing Palaeocene–Middle Eocene flysch of the Louda Kamchiya trough to the north, from the newly formed East Rhodope–West Thrace depression to the south.


1997 ◽  
Vol 37 (1) ◽  
pp. 315 ◽  
Author(s):  
K. K. Romine ◽  
J. M. Durrant ◽  
D. L. Cathro ◽  
G. Bernardel

A regional tectono-stratigraphic framework has been developed for the Cretaceous and Tertiary section in the Northern Carnarvon Basin. This framework places traditional observations in a new context and provides a predictive tool for determining the temporal occurrence and spatial distribution of the lithofacies play elements, that iss reservoir, source and seal.Two new, potential petroleum systems have been identified within the Barremian Muderong Shale and Albian Gearle Siltstone. These potential source rocks could be mature or maturing along a trend that parallels the Alpha Arch and Rankin Platform, and within the Exinouth Sub-basin.A favourable combination of reservoir and seal can be predicted for the early regressive part of the Creta- ceous-Tertiary basin phase (Campanian-Palaeocene). Lowstand and transgressive (within incised valleys) reservoirs are more likely to be isolated and encased in sealing shales, similar to lowstand reservoir facies deposited during the transgressive part of the basin phase, for example, the M. australis sand play.The basin analysis revealed the important role played by pre-existing Proterozoic-Palaeozoic lineaments during extension, and the subsequent impact on play elements, in particular, the distribution of reservoir, fluid migration, and trap development. During extension, the north-trending lineaments influenced the compart mentalisation of the Northern Carnarvon Basin into discrete depocentres. Relay ramp-style accommodation zones developed, linking the sub-basins, and acting as pathways for sediment input into the depocentres and, later in the basin's history, as probable hydrocarbon migration pathways. The relay accommodation zones are a dynamic part of the basin architecture, acting as a focal point for response to intraplate stresses and the creation, modification and destruction of traps and migration pathways.


1975 ◽  
Vol 15 (2) ◽  
pp. 72
Author(s):  
Phillip E. Playford

Modern petroleum exploration has been in progress in Western Australia since 1952, and has been concentrated mainly in the Perth, Carnarvon, Canning, and Bonaparte Gulf Basins. Two large onshore fields have been developed, the Barrow Island oilfield in the Carnarvon Basin (found in 1964), and the Dongara gasfield in the Perth Basin (found in 1966). Small gasfields have also been developed at Mondarra, Gingin, and Walyering in the Perth Basin, but Gingin and Walyering are now virtually depleted.Major gas-condensate fields have been found offshore. These are the North Rankin, Goodwyn, West Tryal Rocks, and Angel fields in the northern Carnarvon Basin, and the Scott Reef field in the Browse Basin. They were found during the period 1971 to 1973, but none has yet been developed.Since 1968 the accent has been on offshore exploration, and this reached a peak in 1972. Exploration activity, both onshore and offshore, is currently declining, owing to the lack of recent success and the unfavourable exploration climate prevailing in Australia today.Original reserves in the Dongara gasfield amounted to about 13 billion cubic metres, of which nearly 2.1 billion have now been produced. Current gas production from Dongara and the small adjoining Mondarra field is about 2.2 million cubic metres per day, and production will continue at about this rate until 1981, after which it will begin declining. Production will fall steeply in 1987, when existing contracts expire. At that time about 90% of the reserves will have been depleted.The original in-place reserves of the Barrow Island oil-field amounted to some 750 million barrels, and it is expected that about 240 million will be recovered. Current oil production is around 37,000 barrels per day, compared with the peak of 48.000 barrels per day reached in 1970. Nearly 43% of the original reserves have now been produced.Total reserves of the major fields in the offshore northern Car-narvon Basin (in the proved and probable categories) are more than 345 billion cubic metres of gas and 320 million barrels of condensate. Of these amounts more than 220 billion cubic metres of gas and 180 million barrels of condensate are in the North Rankin field, which is the largest gasfield in Australia and is a giant by world standards. This is followed by Goodwyn (about 65 billion cubic metres of gas and 90 million barrels of condensate), West Tryal Rocks (more than 30 billion cubic metres of gas) and Angel (about 30 billion cubic metres of gas and 50 million barrels of condensate).Further drilling will be required before gas reserves of the Scott Reef field can be estimated, but the results of the first well and the size of the structure indicate that they could be very large. It is clear that future exploration in Western Australia will be mainly concentrated offshore, in the Carnarvon, Browse, Bonaparte Gulf, and Perth Basins. However, there are still some prospective onshore areas in the Perth, Carnarvon, and Canning Basins.The chances of finding giant oilfields in Western Australia have declined markedly in recent years, as It seems that the generative sequences are mainly gas prone, and most of the obvious structures have now been drilled. However, the prospects are good for further large gas discoveries, and there is a reasonable chance that significant oil reserves will also be found.


2021 ◽  
Vol 61 (2) ◽  
pp. 600
Author(s):  
Michael Curtis ◽  
Simon Holford ◽  
Mark Bunch ◽  
Nick Schofield

The Northern Carnarvon Basin (NCB) forms part of the North West Australian margin. This ‘volcanic’ rifted margin formed as Greater India rifted from the Australian continent through the Jurassic, culminating in breakup in the Early Cretaceous. Late Jurassic to Early Cretaceous syn-rift intrusive magmatism spans 45000km2 of the western Exmouth Plateau and the Exmouth Sub-basin; however, there is little evidence of associated contemporaneous volcanic activity, with isolated late Jurassic volcanic centres present in the central Exmouth Sub-basin. The scarcity of observed volcanic centres is not typical of the extrusive components expected in such igneous provinces, where intrusive:extrusive ratios are typically 2–3:1. To address this, we have investigated the processes that led to the preservation of a volcanic centre near the Pyrenees field and the Toro Volcanic Centre (TVC). The volcanic centre near the Pyrenees field appears to have been preserved from erosion associated with the basin-wide KV unconformity by fault-related downthrow. However, the TVC, which was also affected by faulting, is located closer to the focus of regional early Cretaceous uplift along the Ningaloo Arch to the south and was partly eroded. With erosion of up to 2.6km estimated across the Ningaloo Arch, which, in places, removed all Jurassic strata, we propose that the ‘Exmouth Volcanic Province’ was originally much larger, extending south from the TVC into the southern Exmouth Sub-basin prior to regional uplift and erosion, accounting for the ‘missing’ volume of extrusive igneous material in the NCB.


Author(s):  
Г.П. Яроцкий ◽  
Х.О. Чотчаев

Актуальность рассматриваемой темы в том, что орогенные пояса материковой части Камчатского края насыщены полезными ископаемыми, приуроченных к поясам, образованным последовательным приростом окраин континента от древних с северо-запада к юго-востоку. Такими поясами с месторождениями Ag, Au, Sn, Hg, S являются Северо-Западно-Корякский олигоценовый и Южно-Корякский миоценовый, образованные на северной и южной границе Центрально-Корякской окраины позднемелового континента. Они сформированы в олигоцене и миоцене изолированными вулканогенами локальных андезитовых полей, прорванных гранитоидами тектонической активизации. С ними связаны рудные площади, локализация которых позволит обеспечить прирост запасов разрабатываемых россыпей платиноидов. Цель работы заключается в установлении тектонических закономерностей образования вулканогенов, связанных с ними рудных районов и получения новых данных по их прогнозу. В Северо-Западном поясе оформилась металлогеническая зона с Уннэйваямским, Гайчаваямским и Пальматкинским районами, сопряжёнными с одноименными вулканогенами, в Южно-Камчатском с Ветроваямским вулканогеном. Методология и методы исследования. Методология заключена в глыбово-клавишной структуре литосферы и её земной коры на активных окраинах континента. Методика основана на установлении системной связи структурных элементов геолого-геофизической системы тектоника-вулканогены . Результаты работ и их анализ. Предложена схема закономерностей размещения известных и прогнозируемых рудных районов, узлов юго-запада Корякского нагорья. Они обусловлены глыбово-клавишной тектоникой и локализованы в звеньях серии продольных субпараллельных разновозрастных региональных структур СВ простирания, последовательно наращивающих континент к юго-востоку. Звенья являются дискретными и определяют размеры рудных районов. Рассмотрены выделяемые звенья Северо-Западно-Корякского олигоценового и Южно-Корякского миоценового поясов. В первом СЗ поперечными межглыбовыми разломами литосферы образованы вулканогены гнездового типа. Они возникли на пересечении фундамента позднего мела и южной окраины сопредельной Пенжинской СФЗ поперечными межглыбовыми разломами. В пересечениях образуется литосферный столб вещества гранитоидной активизации верхней мантии и позднемелового осадочного разреза фундамента. Делается вывод, что в Южно-Корякском поясе вулканоген является линейным, образованным заключением линейного СВ Ветроваямского выступа фундамента и чехла между двумя поперечными межглыбовыми разломами. В нём рудоносными вторичными кварцитами создан Ильпинский рудный район с крупными месторождениями самородной серы с Ag, Au, Hg, S. Орогенный вулканизм на активных окраинах континентов сопряжён с основными элементами тектоники и магматизма, создавшими условия образования минерагенических таксонов. На примерах орогенных поясов олигоцена и миоцена очевидна роль геотектонических и металлогенических аспектов авторской методологии глыбово-клавишной структуры литосферы активных окраин. Она эффективна в прогнозе рудных площадей и их оценке последующими геологоразведочными работами. The relevance of the work is that the orogenic belts of the mainland of the Kamchatka Territory are saturated with minerals confined to the belts formed by the successive growth of the continental margins from the ancient ones from the north-west to the south-east. Such belts with deposits of Ag, Au, Sn, Hg, S are the Northwest Koryak Oligocene and South Koryak Miocene, formed on the northern and southern borders of the Central Koryak margin of the Late Cretaceous continent. They are formed in the Oligocene and Miocene by isolated volcanogens of local andesitic fields, broken by granitoids of tectonic activation. Ore areas are associated with them, the localization of which will ensure an increase in the reserves of developed placer deposits. The purpose of the work is to establish tectonic patterns of formation of volcanogens, associated ore regions and obtain new data on their forecast. In the North-Western zone, a metallogenic zone took shape with the Unneivayamsky, Gaichavayamsky and Palmatkinsky regions, associated with the same named volcanogenes, in the South Kamchatka - with the Vetrovayamsky volcanogen. Methodology and research methods. The methodology lies in the block-key structure of the lithosphere and its earths crust on the active margins of the continent. The methodology is based on establishing a systemic connection between the structural elements of the geological and geophysical system tectonics-volcanogens. The results of the work and their analysis. A scheme of patterns of distribution of known and predicted ore regions, nodes of the south-west of the Koryak upland is proposed. They are caused by block-key tectonics and are localized in the links of a series of longitudinal subparallel regionally different age structures of NE strike, successively expanding the continent to the southeast. The links are discrete and determine the size of the ore regions. The distinguished links of the Northwest Koryak Oligocene and South Koryak Miocene belts are considered. In the first northwestern region, nesting volcanogens are formed by transverse interblock faults of the lithosphere. They arose at the intersection of the Late Cretaceous foundation and the southern edge of the adjacent Penzhinsk structural-facial zone with transverse interblock faults. At the intersections, a lithospheric column of granitoid activation matter of the upper mantle and the Late Cretaceous sedimentary section of the basement is formed. It is concluded that the volcanogen in the South Koryak belt, has a linear nature, formed by the conclusion of a linear NE of Vetrovayamsk ledge of the basement and cover between two transverse interblock faults. There ore-bearing secondary quartzites created the Ilpinsk ore region with large deposits of native sulfur with Ag, Au, Hg, S. The orogenic volcanism on the active margins of the continents is associated with the basic elements of tectonics and magmatism, which created the conditions for the formation of minerogenic taxons. The role of geotectonic and metallogenic aspects of the authors methodology of the block-key structure of the active lithosphere margins is evident on the examples of the orogenic Oligocene and Miocene belts. It is effective in forecasting ore areas and evaluating them with subsequent exploration works


1982 ◽  
Vol 8 ◽  
pp. 28-32
Author(s):  
Fritz Lyngsie Jacobsen ◽  
Jørgen Gutzon Larsen

In North-West Europe two mega-basins began their development during Late Carboniferous to Early Permian: The South Permian Basin stretching from eastern England into Poland , and the North Permian Basin reaching from Scotland into Denmark. These two basins were separated by the Mid North Sea High and the Ringkøbing-Fyn High which came into existence early in Permian. The initial phase of subsidence was accompanied by extensive subaerial volcanism. This was followed by a period of oxidation and erosion under desert conditions and deposition of red beds and sabkha sediments in the two Permian basins (fig. 19). These rocks are included in the Rotliegendes Group as originally established by Werner (1786). Continuous subsidence and transgression of the sea, but with a restricted connection to the ocean, lead to the formation of the evaporites of the Zechstein Group.


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