Deglacial mesophotic reef demise on the Great Barrier Reef

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doi: 10.1016/j.palaeo.2013.09.032
Author(s): Abbey, E.; Webster, J. M.; Braga, J. C.; Jacobsen, G. E.; Thorogood, G.; Thomas, A. L.; Camoin, G.; Reimer, P. J.; Potts, D. C.
Author Affiliation(s): Primary:
University of Sydney, Geocoastal Research Group, Sydney, N.S.W., Australia
Universidad de Granada, Spain
Australian Nuclear Science and Technology Organization, Australia
University of Oxford, United Kingdom
Aix-Marseille Université, France
Queen's University Belfast, United Kingdom
University of California at Santa Cruz, United States
Volume Title: Palaeogeography, Palaeoclimatology, Palaeoecology
Source: Palaeogeography, Palaeoclimatology, Palaeoecology, Vol.392, p.473-494. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0031-0182 CODEN: PPPYAB
Note: In English. 108 refs.; illus., incl. charts, 9 tables, sketch map
Summary: Submerged reefs are important recorders of palaeo-environments and sea-level change, and provide a substrate for modern mesophotic (deep-water, light-dependent) coral communities. Mesophotic reefs are rarely, if ever, described from the fossil record and nothing is known of their long-term record on Great Barrier Reef (GBR). Sedimentological and palaeo-ecological analyses coupled with 67 14C AMS and U-Th radiometric dates from dredged coral, algae and bryozoan specimens, recovered from depths of 45 to 130m, reveal two distinct generations of fossil mesophotic coral community development on the submerged shelf edge reefs of the GBR. They occurred from 13 to 10ka and 8ka to present. We identified eleven sedimentary facies representing both autochthonous (in situ) and allochthonous (detrital) genesis, and their palaeo-environmental settings have been interpreted based on their sedimentological characteristics, biological assemblages, and the distribution of similar modern biota within the dredges. Facies on the shelf edge represent deep sedimentary environments, primarily forereef slope and open platform settings in palaeo-water depths of 45-95m. Two coral-algal assemblages and one non-coral encruster assemblage were identified: 1) Massive and tabular corals including Porites, Montipora and faviids associated with Lithophylloids and minor Mastophoroids, 2) platy and encrusting corals including Porites, Montipora and Pachyseris associated with melobesioids and Sporolithon, and 3) Melobesiods and Sporolithon with acervulinids (foraminifera) and bryozoans. Based on their modern occurrence on the GBR and Coral Sea and modern specimens collected in dredges, these are interpreted as representing palaeo-water depths of <60m, <80-100m and >100 m respectively. The first mesophotic generation developed at modern depths of 85-130m from 13 to 10.2 ka and exhibit a deepening succession of <60 to >100 m palaeo-water depth through time. The second generation developed at depths of 45-70 m on the shelf edge from 7.8 ka to present and exhibit stable environmental conditions through time. The apparent hiatus that interrupted the mesophotic coral communities coincided with the timing of modern reef initiation on the GBR as well as a wide-spread flux of siliciclastic sediments from the shelf to the basin. For the first time we have observed the response of mesophotic reef communities to millennial scale environmental perturbations, within the context of global sea-level rise and environmental changes. Abstract Copyright (2013) Elsevier, B.V.
Year of Publication: 2013
Key Words: 24 Surficial Geology, Quaternary Geology; Absolute age; Algae; Anthozoa; Bathymetry; Boundstone; Bryozoa; C-14; Carbon; Carbonate rocks; Cenozoic; Cnidaria; Continental shelf; Coral Sea; Corallinaceae; Dates; Deep-water environment; Deglaciation; Depth; Ecology; Environmental analysis; Facies; Foraminifera; Global change; Great Barrier Reef; Holocene; Hydrographers Passage; Invertebrata; Isotopes; Lithofacies; Marine environment; Mesophotic environment; Noggin Pass; Outer shelf; Pacific Ocean; Paleoecology; Plantae; Pleistocene; Protista; Quaternary; Radioactive isotopes; Rhodophyta; Ribbon Reef; Sea-level changes; Sedimentary rocks; Shelf environment; Slope environment; South Pacific; Southwest Pacific; Submergence; Th/U; Upper Pleistocene; Viper Reef; West Pacific
Coordinates: S194800 S194200 E1502900 E1501300
S185500 S184500 E1483000 E1482500
S170900 S170100 E1463600 E1463200
S153000 S152200 E1454900 E1454700
Record ID: 2014016577
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands