Provenance of sandstones in the Hastings Block, southern New England Orogen: implications for tectonic setting

Abstract

The Devonian–Carboniferous sandstones in the Hastings Block, southern New England Orogen have a predominantly arc-like provenance based on ternary QFL or QmFLt ternary diagrams and have a lower quartz content than Permian sandstones. Stratigraphically correlated formations show similar QFL components but not the same patterns of sandstone compositional variability for formations that outcrop over a wide area such as the Mingaletta and Pappinbarra formations. It is possible to correlate most of the petrological intervals in the Tamworth Belt with the Hastings Block. The trend of petrofacies from Devonian to Permian for the southern Tamworth Belt, Tamworth Belt overall and Hastings Block, is towards sandstone with more monocrystalline quartz and less feldspar and lithics. The areal pattern of sandstone compositions within individual formations shows similarities in the percentage of quartz, feldspar or lithics. This suggests areal continuity of sandstone compositions within a formation during deposition and that the faulting did not substantially change the formations continuity at the time of deposition. The arc-like provenance of Devonian to Permian sandstones within the Hastings Block indicates that the block was likely an along-strike continuation of the Tamworth Belt.

KEY POINTS

1. The Devonian–Carboniferous sandstones have predominantly arc-like provenance on QFL or QmFLt ternary plots with a higher quartz content in younger formations.

2. The Hastings Block and Tamworth Belt sandstones of comparable age are similar but not the same on ternary QFL and QmFLt plots.

3. The areal pattern of the composition of sandstones within formations suggests that faulting was not active during deposition.

Keywords:

• sandstone provenance
• Hastings Block
• Tamworth Belt
• arc source rocks
• subduction–accretion source

Acknowledgements

We thank Peter Cawood, Chris Fergusson, Evan Leitch, Robin Offler and Uri Shanaan for reviewing this paper and making many insightful comments and suggestions for improvements to the paper. John Roberts is thanked for encouraging and organising the collection of point-counted data on the sandstones from the Hastings Block using trained, senior undergraduates within the former Department of Applied Geology, UNSW. His willingness to share his extensive knowledge of the SNEO was much appreciated over many years.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

All the data from these 400 sandstone samples within the HB are available to other researchers (Supplemental Data).

Additional information

Funding

The UNSW School of BEES is acknowledged for providing support for fieldwork. ARC grant A38830545 (1989–1991) funded the point-counting reported in this paper. Jie Yan acknowledges the support from the National Natural Science Funds of China [41902075, 41962007, 42002091], Jiangxi Provincial Natural Science Foundation [20212BAB213009], and Science and Technology Research Project of Department of Education, Jiangxi Province [GJJ200767], the Chinese Government for his PhD scholarship and the 2013 PESA Tertiary Institution Study Grant.