<P> 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 km . </P> <P> On the west is 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 (310 - 210 Mya). 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 . </P>

When were the units of the lachlan fold belt formed