Stratigraphic and structural synthesis of the New England Orogen
Titel:
Stratigraphic and structural synthesis of the New England Orogen
Auteur:
Korsch, R. J. Harrington, H. J.
Verschenen in:
Australian journal of earth sciences
Paginering:
Jaargang 28 (1981) nr. 1-2 pagina's 205-226
Jaar:
1981-04
Inhoud:
It is difficult to determine the ages of thick stratigraphic units in different parts of the Tablelands Complex in New England, because of a scarcity of fossils and the effects of superposed deformations. Many problems disappear if it is assumed that the Silverwood Group is in part Lower Permian and that its Ordovician and Devonian fossils are in olistoliths derived from the Thanes Creek Slate to the W of the Con-damine Fault. With that assumption it is possible to divide the Tablelands Complex into four main layers, which in upward order consist of the following sedimentary associations: (1) Woolomin (?Devonian), (2) Sandon and Beenleigh (Late Devonian to Carboniferous), (3) Nambucca, Silverwood and Coffs Harbour (?Late Carboniferous to Early Permian), and (4) Dummy Creek (Late Permian). The four layers can be extended to include sets of stratigraphic units in the Tamworth Belt and Gunnedah Basin. Four principal sets of regional deformations are identified, and correlated through New England. All the deformations occurred over a considerable period, and each could be a multiphase event. The inferred ages of the deformations are: Dl— pre-Late Carboniferous (could extend back into Devonian); D2—Late Carboniferous to Early Permian (c. 295 Ma); D3—Early Permian (c. 273 Ma); D4—Late Permian (c. 250 Ma). There are resultant structural interference patterns, the most intense being caused by the superposition of the D4 structures on D3 structures.
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