Betzler, Christian; Lindhorst, Sebastian; Lüdmann, Thomas; Weiß, Benedikt; Wunsch, Marco; Braga, Juan-Carlos (2016): Grain size distribution of the lagoonal deposits within the South Malé Atoll, Maldives, Indian Ocean [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.858886, Supplement to: Betzler, C et al. (2015): The leaking bucket of a Maldives atoll: Implications for the understanding of carbonate platform drowning. Marine Geology, 366, 16-33, https://doi.org/10.1016/j.margeo.2015.04.009
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Abstract:
Seismic and multibeam data, as well as sediment samples were acquired in the South Malé Atoll in the Maldives archipelago in 2011 to unravel the stratigraphy and facies of the lagoonal deposits. Multichannel seismic lines show that the sedimentary succession locally reaches a maximum thickness of 15-20 m above an unconformity interpreted as the emersion surface which developed during the last glacial sea-level lowstand. Such depocenters are located in current-protected areas flanking the reef rim of the atoll or in infillings of karst dolinas. Much of the 50 m deep sea floor in the lagoon interior is current swept, and has no or very minor sediment cover. Erosive current moats line drowned patch reefs, whereas other areas are characterized by nondeposition. Karst sink holes, blue holes and karst valleys occur throughout the lagoon, from its rim to its center. Lagoonal sediments are mostly carbonate rubble and coarse-grained carbonate sands with frequent large benthic foraminifers, Halimeda flakes, red algal nodules, mollusks, bioclasts, and intraclasts, some of them glauconitic, as well as very minor ooids. Finer-grained deposits locally are deposited in current-protected areas behind elongated faros, i.e., small atolls which are part of the rim of South Malé Atoll. The South Malé Atoll is a current-flushed atoll, where water and sediment export with the open sea is facilitated by the multiple passes dissecting the atoll rim. With an elevated reef rim and tower-like reefs in the atoll interior it is an example of a leaky bucket atoll which shares characteristics of incipiently drowned carbonate banks or drowning sequences as known from the geological record.
Coverage:
Median Latitude: 4.049945 * Median Longitude: 73.212999 * South-bound Latitude: 3.887480 * West-bound Longitude: 72.745700 * North-bound Latitude: 4.266230 * East-bound Longitude: 73.521220
Date/Time Start: 2011-11-16T00:00:00 * Date/Time End: 2011-11-28T00:00:00
Minimum DEPTH, sediment/rock: 0 m * Maximum DEPTH, sediment/rock: 0 m
Event(s):
Parameter(s):
# | Name | Short Name | Unit | Principal Investigator | Method/Device | Comment |
---|---|---|---|---|---|---|
1 | Sample code/label | Sample label | Betzler, Christian | |||
2 | DATE/TIME | Date/Time | Betzler, Christian | Geocode | ||
3 | LATITUDE | Latitude | Betzler, Christian | Geocode | ||
4 | LONGITUDE | Longitude | Betzler, Christian | Geocode | ||
5 | Depth, bathymetric | Bathy depth | m | Betzler, Christian | Echosounder (ECHO) | |
6 | DEPTH, sediment/rock | Depth sed | m | Betzler, Christian | Geocode | |
7 | Size fraction > 2 mm, gravel | >2 mm | % | Betzler, Christian | Grain size, sieving | |
8 | Size fraction > 0.500 mm, gravel | >500 µm | % | Betzler, Christian | ||
9 | Size fraction > 0.250 mm | >250 µm | % | Betzler, Christian | ||
10 | Size fraction > 0.063 mm, sand | >63 µm | % | Betzler, Christian | ||
11 | Size fraction < 0.063 mm, mud, silt+clay | <63 µm | % | Betzler, Christian | ||
12 | Positioning type/details | Pos type | Betzler, Christian | ARGOS satellite-linked dive recorder SDR-T10 |
License:
Creative Commons Attribution 3.0 Unported (CC-BY-3.0)
Size:
426 data points