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that the Lynningtonian stage embraces a wide interval from the late Artinskian to the
Tatarian; the non-marine top of the Permian is apparently not included; and the
Tasmanian Late Permian palynofloras are so impoverished (Calver & others, 1984) as
to render them unhelpful for correlation with the rest of the continent.
The summary stratigraphic chart is based on columns for 52 areas, and also includes
isotopic dates for intrusives in the New England, northeastern Queensland, and
southeastern Queensland regions. Seven time slices were delineated, varying in
length from 9 m.y. (Permian 1) to about 1.7 m.y. (Permian 5) (Table 1). For the most
part, the boundaries of the time slices are based on the presence of significant breaks
or changes in sedimentation. The Period is divisible into three major intervals:
Permian 1-3, characterised by greater than average non-marine sedimentation;
Permian 4-5, with above average marine deposition; and Permian 6-7, which saw the
re-assertion of a long-term progradational trend. The Permian 1-2 boundary is the
alternative position for the base of the Permian at the base of Stage 3a, advocated by
several workers, while the Permian 2-3 boundary lies at the top of Stage 3a and
corresponds to depositional changes in some local areas. The short Permian 5
interval marks a major transgression following tectonism and a hiatus in much of
eastern Australia. Permian 7 represents the culmination of the Late Permian
progradation, when very little marine deposition was taking place. The continental time
slice division is necessarily a compromise in places, and as expected it is not the most
suitable for some particular basins; for example, Banks & Clarke (1987) selected
different time intervals for Tasmania, and Permian 3 covers a variety of events in the
Carnarvon Basin (shallow marine, subaerial erosion, marine transgression, delta
construction, and shallow marine again), only one of which can be shown on the map.
TECTONICS
The depositional areas and structural elements that were active during the Permian are
shown on the Permian structure map, and the timing of both deposition and
deformation is indicated in terms of the time slices used for the Permian
palmogeographic maps. Basins are classified as intracratonic, marginal (or back-arc),
or polyhistory extensional/foreland basins, the latter category referring specifically to
the Sydney-Bowen Basin. An additional category is provided for parts of the New
England Orogen that contain scattered areas, some only fault slivers, of Permian
sediments; this category includes small depositional basins and erosional remnants
of formerly more extensive deposits. Also shown on the map are Permian intrusive
and extrusive rocks, and ultramafic bodies. Structural features include faults (the
nature of which is indicated where known), folds, depocentre axes and trend lines.
Areas which have undergone metamorphism during the Permian are also indicated.
The basin classifications used are described in Totterdell (1990), from which this
Tectonics section is derived.
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