SYDNEY BASIN

Abundance And Distribution Of Fungal Spores In The Sydney Basin



Abundance And Distribution Of Fungal Spores In The Sydney Basin

Introduction

The Lower Whybrow seam is a Guadalupian series, Late Permian coal (Retallack, 1980), from the Hunter Coalfield of the Sydney Basin, New South Wales, Australia ( Fig. 1). The coalfield is situated about 150 km north of Sydney, and covers an area of 2100 km2 (Sniffin and Beckett, 1995).

By the Late Permian a long period of marine regression, the result of eustatic sea level change, had resulted in the deposition of the deltaic and fluvial Wittingham Coal Measures and their equivalents, most notably the Tomago Coal Measures (Britten and McMinn), in the foreland basin setting of the Sydney Basin ( Brakel and Herbert).

The Jerrys Plains Subgroup is up to 800 m in thickness, and contains at least 15 economic coals. It is subdivided into formations by the presence of tuff horizons. The Mount Leonard Formation, on average 40 m thick, is the topmost coal measure formation of the subgroup. It comprises a lower delta plain unit of coarse, massive sandstones or conglomerates, with intercalated thin coal seams.

Materials and Methods

Papers on fusinite/charcoal typically illustrate well-preserved material, whether woods or even flowers ( Falcon and Scott). However, less photogenic structures, such as partially degraded leaves, when charcoalified/fusinised ( Scott, 2000), more closely resemble Gondwanan semifusinite. Therefore, much of the poorly structured semifusinite recorded in Gondwana coals may represent partially humified and subsequently charred tissues, more humified tissues occupying a transitional position to macrinite ( Diessel and Hower).

The abundance of semifusinite in relation to fusinite in Gondwana coals (Diessel, 1992) may in part result from variations in maceral identification. The definition of fusinite as well structured ( ICCP, 1963) has already been recorded. The committee also records a large range of reflectance for semifusinite, from 0.6% to 7%. Poorly structured material may therefore be burned, and can by this definition only be classed as semifusinite. Therefore, if a ground fire burned a peat, as in Borneo in 1982/3 ( Johnson, B., 1984. In: The Great Fire of Borneo, World Wildlife Fund, Godalming, Surrey, UK, p. 24.Johnson, 1984), any remnant, poorly structured, charcoalified material would be classed as semifusinite. Litter fires produce large amounts of charcoal ( Scott, 2000). Therefore, large amounts of semifusinite might be expected, as well as more fragmentary particles. Fine, detrital fragments of fusinite and semifusinite are recorded as inertodetrinite ( Fig. 3A; Falcon and Snyman, 1986).

Results

The wildfire origin of all semifusinite appears to be questioned because of its abundant occurrence and general appearance, which can vary greatly, as illustrated by Falcon and Snyman (1986). The morphology of much of this semifusinite ( Fig. 3D) is at odds with that of classic fusinite/charcoal, which is recognised as having “well defined cellular structure of wood or sclerenchyma” ( ICCP, 1963).

The formation is overlain by the intertidal Denman Formation, a sequence of finer bioturbated sediments (Edwards and Vitnell, 1979), which has been correlated with the Dempsey Formation of the Newcastle Coal ...