Stromatolite research in the Shark Bay World Heritage Area

Three decades after declaration of World Heritage status for Shark Bay new research findings are being reported on the specialised microbial habitats that characterise its hypersaline settings, the composition of microbial communities, tidal flat evolution, stromatolite geochronology and subtidal mi...

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Main Authors: Collins, Lindsay, Jahnert, Ricardo
Format: Journal Article
Published: Royal Society of Western Australia 2014
Subjects:
Online Access:http://hdl.handle.net/20.500.11937/26636
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author Collins, Lindsay
Jahnert, Ricardo
author_facet Collins, Lindsay
Jahnert, Ricardo
author_sort Collins, Lindsay
building Curtin Institutional Repository
collection Online Access
description Three decades after declaration of World Heritage status for Shark Bay new research findings are being reported on the specialised microbial habitats that characterise its hypersaline settings, the composition of microbial communities, tidal flat evolution, stromatolite geochronology and subtidal microbial systems. In the stable, semiarid and evaporative setting within the intertidal–subtidal environment the microbial ecosystem is trapping, binding and biologically inducing carbonate precipitation within laminated stromatolites, non-laminated thrombolitic forms and cryptomicrobial non-laminated forms. Filamentous microbes constitute the dominant group in the blister, tufted and smooth mat types, and coccoid microbes dominate the pustular, colloform and microbial pavement deposit types. Detailed georeferenced substrate mapping has revealed extensive subtidal microbial deposits occupying ~300 km2 of the total Holocene 1400 km2 area of Hamelin Pool. The microbial pavement covers 227 km2 of the subtidal substrate, which together with columnar structures reveals a subtidal microbial habitat that occupies an area several times larger than the area of the intertidal deposits.Oldest dated stromatolite heads are 1915 14C years BP, and the overall system was deposited in two stages: the first between 2000 and 1200 and the last from 900 years BP to the present. Slow accretion rates vary from less than 0.1 to 0.5 mm/year. Different internal fabrics were constructed according to their position in relation to the littoral zone by distinct microbial communities, and lateral fabric relations have been established. Evidence of shallowing-upward fabric sequences of microbial origin reflects relative falling sea levels during the late Holocene and is likely useful in ancient environmental interpretation. A new substrate map and depositional history for this distinctive microbial habitat has established the significance of subtidal structures and emphasises the geoscientific importance of Hamelin Pool, especially with respect to early life studies and ancient analogues for understanding microbial activity, deposit characteristics, fenestral fabrics and distribution.
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spelling curtin-20.500.11937-266362023-02-22T06:24:22Z Stromatolite research in the Shark Bay World Heritage Area Collins, Lindsay Jahnert, Ricardo subtidal stromatolites geochronology microbial mats fabrics microbialites Holocene Three decades after declaration of World Heritage status for Shark Bay new research findings are being reported on the specialised microbial habitats that characterise its hypersaline settings, the composition of microbial communities, tidal flat evolution, stromatolite geochronology and subtidal microbial systems. In the stable, semiarid and evaporative setting within the intertidal–subtidal environment the microbial ecosystem is trapping, binding and biologically inducing carbonate precipitation within laminated stromatolites, non-laminated thrombolitic forms and cryptomicrobial non-laminated forms. Filamentous microbes constitute the dominant group in the blister, tufted and smooth mat types, and coccoid microbes dominate the pustular, colloform and microbial pavement deposit types. Detailed georeferenced substrate mapping has revealed extensive subtidal microbial deposits occupying ~300 km2 of the total Holocene 1400 km2 area of Hamelin Pool. The microbial pavement covers 227 km2 of the subtidal substrate, which together with columnar structures reveals a subtidal microbial habitat that occupies an area several times larger than the area of the intertidal deposits.Oldest dated stromatolite heads are 1915 14C years BP, and the overall system was deposited in two stages: the first between 2000 and 1200 and the last from 900 years BP to the present. Slow accretion rates vary from less than 0.1 to 0.5 mm/year. Different internal fabrics were constructed according to their position in relation to the littoral zone by distinct microbial communities, and lateral fabric relations have been established. Evidence of shallowing-upward fabric sequences of microbial origin reflects relative falling sea levels during the late Holocene and is likely useful in ancient environmental interpretation. A new substrate map and depositional history for this distinctive microbial habitat has established the significance of subtidal structures and emphasises the geoscientific importance of Hamelin Pool, especially with respect to early life studies and ancient analogues for understanding microbial activity, deposit characteristics, fenestral fabrics and distribution. 2014 Journal Article http://hdl.handle.net/20.500.11937/26636 10.1002/2013TC003483 Royal Society of Western Australia unknown
spellingShingle subtidal
stromatolites
geochronology
microbial mats
fabrics
microbialites
Holocene
Collins, Lindsay
Jahnert, Ricardo
Stromatolite research in the Shark Bay World Heritage Area
title Stromatolite research in the Shark Bay World Heritage Area
title_full Stromatolite research in the Shark Bay World Heritage Area
title_fullStr Stromatolite research in the Shark Bay World Heritage Area
title_full_unstemmed Stromatolite research in the Shark Bay World Heritage Area
title_short Stromatolite research in the Shark Bay World Heritage Area
title_sort stromatolite research in the shark bay world heritage area
topic subtidal
stromatolites
geochronology
microbial mats
fabrics
microbialites
Holocene
url http://hdl.handle.net/20.500.11937/26636