Higher-resolution palynostratigraphy of the Norian-Carnian (Triassic) upper Mungaroo Formation, offshore Carnarvon Basin
M. Dixon A , R. Morgan B , J. Goodall B and M. van den Berg AA Shell Development Australia.
B Morgan-Goodall Palaeo Associates.
The APPEA Journal 52(2) 683-683 https://doi.org/10.1071/AJ11097
Published: 2012
Abstract
Palynostratigraphic correlations within the Triassic fluvio-deltaic upper Mungaroo Formation (M. crenulatus and upper S. speciosus zones) of the Carnarvon Basin have proven to be difficult. Although two reliable pollen extinction datums have long been established in the uppermost 200 m of the formation, correlations within the sector below (up to 1,500 m) have had to rely on broad algael and pollen acmes, with variable results.
A revised palynostratigraphic scheme is presented in this extended abstract, which has been largely in use within Shell and Morgan-Goodall Palaeo Associates since mid/late 2010, and which has not been previously published in detail. For consistency, the subzone names remain the same as those in previous use; however, crucially, a framework for their reliable identification in more recently-analysed wells is provided by several Morgan gradational sub-types of key pollen species (viz. of Cycadopites stonei, Ephedripites macistriatus, and Samaropollenites speciosus).
Within this robust framework that is based on top-ranges, base-ranges, and rapid switches in the ratios of gradational and related morphotypes, numerous thin marine incursions and regional to sub-regional swampy phases are evidenced. Lateral and vertical relationships between marine incursions and swampy phases are sometimes apparent, and clustering of a few of the above pollen events at these levels hints at condensation.
The revised framework has been successfully used in the high-resolution, regional-stratigraphic interpretation of both seismic and well data and is contributing to an increasing understanding of the variability of the Upper Mungaroo depositional system in the Greater Carnarvon Basin.
Matt Dixon graduated from UWA with an honours degree (geology) in 2000 and has nearly completed a PhD (also UWA) about high-resolution dinocyst biostratigraphy in the mid-Cretaceous. He has worked under the Morgan Palaeo Associates umbrella since 2006, spending more than a year in total at well sites in Papua New Guinea, and otherwise concentrating on Mesozoic palynology samples from North West Shelf wells (including 34 wells that intersected the present zone). Since 2009, he has spent the majority of his time working for Shell Development Australia, where he is a stratigrapher in the exploration regional team. |
Roger Morgan completed his pass degree at Adelaide University, honours degree in palynology at UWA, and PhD at the University of Adelaide; he completed the last while employed by the NSW Mines Department, Sydney. From there, he moved to Glasgow, Scotland, to work on North Sea sequences (British National Oil Corporation, later Britoil, now part of BP), then he returned to Adelaide to become a consultant and founder of Morgan Palaeo Associates. This company has grown and recently morphed into Morgan Goodall Palaeo Pty Ltd with a group of 14 palynologists servicing the industry needs in Australia, Papua New Guinea, and Indonesia. Management is passing to Jeff Goodall to facilitate Roger’s move to phased retirement. |
Jeffery Goodall completed his BSc (hons) at Kingston University, MSc (palynology) at Sheffield University, and PhD at University College London while employed by the Geochem Group, Chester, UK. From there, he moved to Ichron Ltd, Northwich, UK, to work on North Sea and international projects. In 1998, he migrated to Australia to join Santos for 12 years, working initially as a palynologist then sequence stratigrapher and finally exploration geologist, involved with the broad spectrum of exploration and development interests Santos has in Australia and overseas. In July 2010, he accepted an invitation from Roger Morgan to join Morgan Palaeo Associates and to become a partner in the company—one with a growing portfolio of coal, oil, and gas exploration and development projects. He has also maintained and built on his exploration geology experience with prospect generation and prospect review projects, presently focused primarily in Indonesia. |
Martine van den Berg graduated from Utrecht University, The Netherlands, in 1991 and 1992 with an MSc (geology/geophysics) and an MSc (structural geology). She worked at the Nederlandse Aardolie Maatschappij in the Netherlands as a junior geologist prior to joining Shell International E&P in 1993 and working for Shell UK Exploration & Production in London as an exploration geologist. She subsequently worked at Woodside Offshore Petroleum, in Perth, in 1998 as an exploration geologist and development geophysicist, working several basins along the greater North West Shelf. In 2004, she was posted to Petroleum Development Oman where she worked in the specialist structural geology group and the new opportunity group in exploration. In 2009, she moved back to Perth to work as a senior exploration geologist in Shell Asia Pacific’s new ventures division and Shell Development Australia where she now works in the exploration regional team. Member: PESA, AAPG. |
References
Backhouse, J., and Balme, B.E., 2002—Late Triassic Palynology of the Northern Carnarvon Basin. Report 226. East Perth, WA: Minerals and Energy Research Institute of Western Australia.Bint, A.N., and Helby, R., 1988—Upper Triassic palynofacies and environmental interpretations for the Rankin Trend, Northern Carnarvon Basin. In: Purcell, P.G., and R.R. (eds.) The North West Shelf, Australia: Proceedings of Petroleum Explorations Society of Australia Symposium, Perth, Australia, 30 August–2 September, 589–98.
Dolby, J.H., and Balme, B.E. (1976—). Triassic Palynology of the Carnarvon Basin, Western Australia. Review of Palaeobotany and Palynology 22, 105–68.
Morgan, R., and Dixon, M., 2002—New Triassic Palynology of Guilford-1 (3617.8m–4235/40m) Carnarvon Basin, Western Australia. Report Approval Number: S31981. Perth, WA: Woodside Energy Ltd.
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