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Droxler, André W; Haddad, Geoffrey A; Mucciarone, David A; Cullen, James L (1990): Carbonate composition of Pliocene-Pleistocene sediments of the Maledives [dataset publication series]. PANGAEA, https://doi.org/10.1594/PANGAEA.756140, Supplement to: Droxler, AW et al. (1990): Pleistocene-Pliocene aragonite cyclic variations in holes 714A and 716B (the Maledives) compared with hole 633A (the Bahamas): records of climate-induced CaCO3 preservation at intermediate water depths. In: Duncan, RA; Backmann, J; Peterson, LC; et al. (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 115, 539-577, https://doi.org/10.2973/odp.proc.sr.115.179.1990

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Abstract:
Ocean Drilling Program (ODP) Leg 115 post-cruise research was focused on two Maldives sites, more precisely on the top 108 m of Hole 716B (water depth, 540 m), equivalent to the past 3.5 m.y., and the top 19.5 m of Hole 714A (water depth, 2195 m), equivalent to the past 0.55 m.y. These sediments consist of mostly unaltered and undisturbed, turbidite-free, periplatform ooze. Results of our research are compared with existing data on Hole 633A (water depth, 1681 m), drilled in the Bahamas during ODP Leg 101, using age/depth models built on the basis of oxygen isotope, nannofossil, and magnetic stratigraphies.
Climate-induced, long-term (roughly 0.5 m.y.) aragonite cycles, superposed on short-term (roughly 0.04 and 0.1 m.y.) aragonite cycles, have been established at least during the past 2.0 m.y., in the Maldives and the Bahamas. Our most interesting result is the clear correlation among the aragonite long-term cycles in the Maldives and the Bahamas and the carbonate-preservation, long-term cycles from the open Pacific, Indian, and North Atlantic oceans. The mid-Brunhes dissolution interval, corresponding to the youngest preservation minima of the carbonate-preservation, longterm cycles, is clearly defined by fine aragonite minimum values in the deep periplatform sites, and by maximum fragmentation of pteropod tests in the shallow sites. Aragonite and planktonic d18O records, usually in phase during the late Pleistocene, display, further back in time, discreet intervals where the two records do not match with one another. Major mismatches between both records occur synchronously in the Maldives and Bahamas periplatform sites and seem to correspond to extreme events of either carbonate-preservation or dissolution in the deep pelagic carbonate sites of the equatorial Pacific Ocean.
Based on our findings, short- and long-term aragonite cycles can no longer be explained only by variations of aragonite input from the nearby shallow carbonate banks, in response to their alternate flooding and exposure through cyclic sea-level fluctuations. The aragonite long-term cycles in the periplatform environments are interpreted as carbonatepreservation cycles at intermediate-water depths. Their occurrence shows, therefore, that the carbonate chemistry of the entire water column has been influenced by long-term (0.5 m.y.) cyclic variations during the past 2.0 m.y. These major changes of the water-column carbonate chemistry are linked to the climate-induced carbon cycling among the different atmospheric, oceanic, and sedimentary carbon reservoirs.
Project(s):
Coverage:
Median Latitude: 9.358082 * Median Longitude: 38.731350 * South-bound Latitude: 4.933300 * West-bound Longitude: -75.623500 * North-bound Latitude: 23.688500 * East-bound Longitude: 73.786700
Date/Time Start: 1985-03-01T08:36:00 * Date/Time End: 1987-06-29T00:00:00
Event(s):
101-633A * Latitude: 23.688500 * Longitude: -75.623500 * Date/Time Start: 1985-03-01T08:36:00 * Date/Time End: 1985-03-02T19:48:00 * Elevation: -1690.0 m * Penetration: 227.3 m * Recovery: 111.34 m * Location: South Atlantic Ocean * Campaign: Leg101 * Basis: Joides Resolution * Method/Device: Drilling/drill rig (DRILL) * Comment: 24 cores; 228.3 m cored; 0 m drilled; 48.8 % recovery
115-714A * Latitude: 5.060000 * Longitude: 73.786700 * Date/Time Start: 1987-06-23T03:55:00 * Date/Time End: 1987-06-24T04:15:00 * Elevation: -2041.0 m * Penetration: 233 m * Recovery: 194.63 m * Location: Lakshadweep Sea * Campaign: Leg115 * Basis: Joides Resolution * Method/Device: Drilling/drill rig (DRILL) * Comment: 25 cores; 233 m cored; 0 m drilled; 83.5 % recovery
115-716B * Latitude: 4.933300 * Longitude: 73.283300 * Date/Time: 1987-06-29T00:00:00 * Elevation: -544.0 m * Penetration: 264.4 m * Recovery: 267.36 m * Location: Lakshadweep Sea * Campaign: Leg115 * Basis: Joides Resolution * Method/Device: Drilling/drill rig (DRILL) * Comment: 28 cores; 264.4 m cored; 0 m drilled; 101.1 % recovery
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