气候变化领域集成服务门户(CCPortal): Widespread seagrass meadows during the Early Miocene (Burdigalian) in southwestern Australia paralleled modern seagrass distributions

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DOI	10.1016/j.palaeo.2020.109846
	Widespread seagrass meadows during the Early Miocene (Burdigalian) in southwestern Australia paralleled modern seagrass distributions
	Haig D.W.; Smith M.G.; Riera R.; Parker J.H.
发表日期	2020
ISSN	0031-0182
卷号	555
英文摘要	The Trealla Limestone, which forms a veneer of foraminiferal-rich limestone and covers over 4000 km2 of the tectonically stable Southern Carnarvon Platform, contains the oldest evidence for seagrass meadows known in Western Australia. It belongs to Lower Tf1 Letter Stage (based on larger benthic foraminifers) of the Burdigalian, within interval 19–16 Ma, and is the only Miocene unit on the platform. The Trealla Limestone here is coeval to the deeper water lower part of the much thicker Trealla Limestone in the Exmouth Sub-basin to the northwest. A seagrass-meadow depositional environment is indicated by most of the studied microfacies based on comparisons with modern sediment composition and foraminiferal assemblages found in innermost shelf seagrass banks between 23°S and 32°S on the present Western Australian coast. Some levels in the Trealla Limestone on the platform (e.g. with abundant miliolid foraminifers, and absence of coral debris) probably were deposited in and around dense seagrass meadows similar to those present today in the metahaline (40–55 ppt salinity) reaches of Shark Bay; whereas other levels (e.g. coral floatstone) were deposited under normal-marine conditions. Based on comparisons with modern carbonate sediment and biota in the region, the biogenic composition of the Trealla Limestone on the platform suggests winter minimum sea-surface temperatures within the range of 17–22 °C. The Nullabor Limestone in the Eucla Basin, at 10° further south on the southern Australian margin, is similar, at least in part, in composition and age to the Trealla Limestone on the Southern Carnarvon Platform. Both may have been deposited during a Burdigalian sea-level rise, and during part of the Miocene climate optimum recognized elsewhere. Sediment composition and foraminiferal assemblages (including epiphytic types) found in the Trealla and Nullabor limestones are similar to those in the modern seagrass banks of the region. This suggests that seagrasses similar to the extensive Posidonia and Amphibolus stands, which are dominant today between 25°S and 35°S along the Western Australian coast, were widespread during the Burdigalian. © 2020 Elsevier B.V.
英文关键词	Foraminifera; Inner-neritic microfacies; Nullabor Limestone; Southern Carnarvon Platform; Trealla Limestone
语种	英语
scopus关键词	assembly rule; benthic foraminifera; Burdigalian; carbonate sediment; depositional environment; foraminifera; microfacies; seagrass meadow; spatial distribution; Australia; Eucla Basin; Shark Bay; Western Australia; Amphibolus; Anthozoa; Chondrichthyes; Foraminifera; Miliolina; Posidonia
来源期刊	Palaeogeography, Palaeoclimatology, Palaeoecology
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/150414
作者单位	Oceans Graduate School, The University of Western Australia, 35 Stirling Highway, Perth, Western Australia 6009, Australia; School of Earth Sciences, The University of Western Australia, 35 Stirling Highway, Perth, Western Australia 6009, Australia
推荐引用方式 GB/T 7714	Haig D.W.,Smith M.G.,Riera R.,et al. Widespread seagrass meadows during the Early Miocene (Burdigalian) in southwestern Australia paralleled modern seagrass distributions[J],2020,555.
APA	Haig D.W.,Smith M.G.,Riera R.,&Parker J.H..(2020).Widespread seagrass meadows during the Early Miocene (Burdigalian) in southwestern Australia paralleled modern seagrass distributions.Palaeogeography, Palaeoclimatology, Palaeoecology,555.
MLA	Haig D.W.,et al."Widespread seagrass meadows during the Early Miocene (Burdigalian) in southwestern Australia paralleled modern seagrass distributions".Palaeogeography, Palaeoclimatology, Palaeoecology 555(2020).