skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Debris-flow deposits in an alluvial-plain succession: The upper Triassic Callide coal measures of Queensland, Australia

Abstract

The Carnian-Rhaetian Callide Coal Measures are preserved in a small (22.5 km by 8 km), partially fault-bounded basin remnant in east-central Queensland, Australia. The <150 m thick coal-measure succession is interpreted to have accumulated during a phase of mild crustal extension that formed a series of discrete, intermontane basins in eastern Australia. The succession fines upward from a conglomerate-rich lower part into a finer-grained and coal-bearing upper section (including coal seams <34 m thick), and is interpreted as the deposits of an alluvial-plain environment. Anomalous, matrix-rich diamictites, breccias, and conglomerates have been recognized within the succession at several localities, in many cases interbedded with coals. These are interpreted as the product of debris flows. Two debris-flow lithofacies are recognized: (1) mixtures of fine carbonaceous material, clay, silt, sand, gravel, and volcaniclastic debris, and (2) breccias consisting principally of coal clasts in a coaly matrix with minor clastic and volcaniclastic debris. The distribution of debris flows in the Callide Coal Measures shows a coincidence with mapped faults and interpreted structural lineaments. The debris flows may have been triggered by fault movements, which formed rupture topography on the flat alluvial plain, and caused destabilization of water-saturated clastic and organic sediments. Some debris-flowmore » bodies may have been mounded, such that subsequent peat formation was restricted until those bodies were buried. The preservation of debris-flow units at different stratigraphic levels along mapped structures suggests multiple paleoseismic events or multiple debris-flow units at different stratigraphic levels along mapped structures suggests multiple paleoseismic events or multiple debris-flow events along those structures. The mixing of volcaniclastic debris into debris-flow facies suggests that seismic events were coincident with (or perhaps caused by) nearby, explosive volcanic activity. The close relationship between debris-flow deposits and thick coal bodies on the inferred downthrown sides of faults at Callide further suggests that periodic, tectonic subsidence may have facilitated thick coal accumulation.« less

Authors:
;  [1]
  1. Univ. of Queensland, Brisbane (Australia). Dept. of Earth Sciences
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
697147
Resource Type:
Journal Article
Journal Name:
Journal of Sedimentary Research, Section A: Sedimentary Petrology and Processes
Additional Journal Information:
Journal Volume: 69; Journal Issue: 5; Other Information: PBD: Sep 1999
Country of Publication:
United States
Language:
English
Subject:
01 COAL, LIGNITE, AND PEAT; QUEENSLAND; COAL DEPOSITS; SEDIMENTATION; COAL SEAMS; THICKNESS; GEOLOGIC FAULTS; GEOLOGIC HISTORY

Citation Formats

Jorgensen, P.J., and Fielding, C.R. Debris-flow deposits in an alluvial-plain succession: The upper Triassic Callide coal measures of Queensland, Australia. United States: N. p., 1999. Web. doi:10.2110/jsr.69.1027.
Jorgensen, P.J., & Fielding, C.R. Debris-flow deposits in an alluvial-plain succession: The upper Triassic Callide coal measures of Queensland, Australia. United States. doi:10.2110/jsr.69.1027.
Jorgensen, P.J., and Fielding, C.R. Wed . "Debris-flow deposits in an alluvial-plain succession: The upper Triassic Callide coal measures of Queensland, Australia". United States. doi:10.2110/jsr.69.1027.
@article{osti_697147,
title = {Debris-flow deposits in an alluvial-plain succession: The upper Triassic Callide coal measures of Queensland, Australia},
author = {Jorgensen, P.J. and Fielding, C.R.},
abstractNote = {The Carnian-Rhaetian Callide Coal Measures are preserved in a small (22.5 km by 8 km), partially fault-bounded basin remnant in east-central Queensland, Australia. The <150 m thick coal-measure succession is interpreted to have accumulated during a phase of mild crustal extension that formed a series of discrete, intermontane basins in eastern Australia. The succession fines upward from a conglomerate-rich lower part into a finer-grained and coal-bearing upper section (including coal seams <34 m thick), and is interpreted as the deposits of an alluvial-plain environment. Anomalous, matrix-rich diamictites, breccias, and conglomerates have been recognized within the succession at several localities, in many cases interbedded with coals. These are interpreted as the product of debris flows. Two debris-flow lithofacies are recognized: (1) mixtures of fine carbonaceous material, clay, silt, sand, gravel, and volcaniclastic debris, and (2) breccias consisting principally of coal clasts in a coaly matrix with minor clastic and volcaniclastic debris. The distribution of debris flows in the Callide Coal Measures shows a coincidence with mapped faults and interpreted structural lineaments. The debris flows may have been triggered by fault movements, which formed rupture topography on the flat alluvial plain, and caused destabilization of water-saturated clastic and organic sediments. Some debris-flow bodies may have been mounded, such that subsequent peat formation was restricted until those bodies were buried. The preservation of debris-flow units at different stratigraphic levels along mapped structures suggests multiple paleoseismic events or multiple debris-flow units at different stratigraphic levels along mapped structures suggests multiple paleoseismic events or multiple debris-flow events along those structures. The mixing of volcaniclastic debris into debris-flow facies suggests that seismic events were coincident with (or perhaps caused by) nearby, explosive volcanic activity. The close relationship between debris-flow deposits and thick coal bodies on the inferred downthrown sides of faults at Callide further suggests that periodic, tectonic subsidence may have facilitated thick coal accumulation.},
doi = {10.2110/jsr.69.1027},
journal = {Journal of Sedimentary Research, Section A: Sedimentary Petrology and Processes},
number = 5,
volume = 69,
place = {United States},
year = {1999},
month = {9}
}