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Lachlan Fold Belt AI simulator
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Hub AI
Lachlan Fold Belt AI simulator
(@Lachlan Fold Belt_simulator)
Lachlan Fold Belt
The Lachlan Fold Belt (LFB) or Lachlan Orogen is a geological subdivision of the east part of Australia. It is a zone of folded and faulted rocks of similar age. It dominates New South Wales and Victoria, also extending into Tasmania, the Australian Capital Territory and Queensland. It was formed in the Middle Paleozoic from 450 to 340 Mya. It was earlier known as Lachlan Geosyncline. It covers an area of 200,000 km2.
The Lachlan Fold Belt is bordered on the west by the Delamerian Orogen from the early Palaeozoic (550 to 470 Mya). On the east side is found the Narooma Accretionary Complex (or Narooma terrane) from 445 Mya, and the New England Orogen from late Palaeozoic to early Mesozoic. These boundary orogens along with the Lachlan Orogen make up the Tasman Orogenic System in Australia, which along with the extension into the neighbouring parts of Gondwana make up the Tasmanides. North of the Lachlan Fold belt is the Thomson Orogen in the north east and centre of Queensland. Sometimes the Lachlan Orogen is included with the Thomson Orogen and known as the 'Lachlan-Thomson Orogen'. The Great Artesian Basin has been laid down over the top of the LFB in northwestern New South Wales and western Queensland and the Murray-Darling Basin covers the southwest of New South Wales. The Sydney Basin is on the top of the LFB around Sydney and Wollongong on the east coast of New South Wales.
In Victoria the western limit of the LFB is defined by the Stawell-Ararat Fault. Westwards of this fault is the Moornambool Metamorphic Complex.
The orogen is of the accretionary or 'Turkic' type. It has also been classified as a 'Carpathian' type orogen, i.e. one where subduction rate is greater than that of plate convergence. In such a case the 'hinge', at which subduction starts, tend to move further seawards over time (rollback).
The Tasman Line outlines the Precambrian margin of eastern Australia. The Delamerian Orogen follows this line, and the western side of the Lachlan Orogen also follows this curve. The central and east parts of the Orogen are aligned in a north–south direction.
At the present time the fold belt is about 1000 km wide. However the original width was 2000 to 3000 km wide, with the excess size absorbed by folding and thrusting.
Rock beds are folded in chevron folds. They are cut by thin skinned thrusts. Other faults separate the different terranes making up the orogen.
Before the concept of plate tectonics was accepted, the LFB was described as the Lachlan Geosyncline.
Lachlan Fold Belt
The Lachlan Fold Belt (LFB) or Lachlan Orogen is a geological subdivision of the east part of Australia. It is a zone of folded and faulted rocks of similar age. It dominates New South Wales and Victoria, also extending into Tasmania, the Australian Capital Territory and Queensland. It was formed in the Middle Paleozoic from 450 to 340 Mya. It was earlier known as Lachlan Geosyncline. It covers an area of 200,000 km2.
The Lachlan Fold Belt is bordered on the west by the Delamerian Orogen from the early Palaeozoic (550 to 470 Mya). On the east side is found the Narooma Accretionary Complex (or Narooma terrane) from 445 Mya, and the New England Orogen from late Palaeozoic to early Mesozoic. These boundary orogens along with the Lachlan Orogen make up the Tasman Orogenic System in Australia, which along with the extension into the neighbouring parts of Gondwana make up the Tasmanides. North of the Lachlan Fold belt is the Thomson Orogen in the north east and centre of Queensland. Sometimes the Lachlan Orogen is included with the Thomson Orogen and known as the 'Lachlan-Thomson Orogen'. The Great Artesian Basin has been laid down over the top of the LFB in northwestern New South Wales and western Queensland and the Murray-Darling Basin covers the southwest of New South Wales. The Sydney Basin is on the top of the LFB around Sydney and Wollongong on the east coast of New South Wales.
In Victoria the western limit of the LFB is defined by the Stawell-Ararat Fault. Westwards of this fault is the Moornambool Metamorphic Complex.
The orogen is of the accretionary or 'Turkic' type. It has also been classified as a 'Carpathian' type orogen, i.e. one where subduction rate is greater than that of plate convergence. In such a case the 'hinge', at which subduction starts, tend to move further seawards over time (rollback).
The Tasman Line outlines the Precambrian margin of eastern Australia. The Delamerian Orogen follows this line, and the western side of the Lachlan Orogen also follows this curve. The central and east parts of the Orogen are aligned in a north–south direction.
At the present time the fold belt is about 1000 km wide. However the original width was 2000 to 3000 km wide, with the excess size absorbed by folding and thrusting.
Rock beds are folded in chevron folds. They are cut by thin skinned thrusts. Other faults separate the different terranes making up the orogen.
Before the concept of plate tectonics was accepted, the LFB was described as the Lachlan Geosyncline.