Modern periplatform highstand shedding of two semidrowned or drowned shallow carbonate systems, Pedro Bank and the southern shelf of Jamaica, northern Nicaragua Rise

Conference · Tue May 01 04:00:00 EDT 1990 · AAPG Bulletin (American Association of Petroleum Geologists); (USA)

OSTI ID:7061360

Droxler, A W; Glaser, K S ^[1]

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1. Rice Univ., Houston, TX (USA)

Water depth as well as bank-top sediment cover and thickness are the most commonly used criteria to determine whether a modern carbonate bank is drowned or semidrowned. Because neritic carbonate production appears to drop by a factor of two in water depths ranging between 10 and 20 m, it is believed that the limit of neritic carbonate production is the main constraint on the drowning of modern carbonate platforms. Because the shallow isolated carbonate banks on the northern Nicaragua Rise, on the Nicaragua/Honduras and southern Jamaica carbonate shelves, and on many other modern carbonate banks worldwide are covered by an average of 20 to 30 m or more of water and usually by coarse carbonate sediment, carbonate sedimentologists have considered these banks good examples of semidrowned or even drowned carbonate banks. Based on recent research on the northern Nicaragua Rise, however, the authors can demonstrate that these banks are today still healthy producers of large volumes of periplatform sediment (fine aragonite and magnesian calcite), which are almost totally exported to the deep surrounding slopes. These sediments, deposited during the past 9,000 yr, form periplatform wedges that are defined on 3.5-kHz profiles. Radiocarbon ages of the wedge surface sediment, ranging between 230 and 610 yr ago, are clear evidence for contemporaneous production of sediments on the shallow bank and shelf, and their instantaneous export to the upper slopes. For the last 5,000 yr, sedimentation rates ranging from 2,000 mm/k.y. off Pedro Bank to 1,300 mm/k.y. off Jamaica are comparable to sedimentation rates on the slopes of Great Bahama Bank, ranging between 2,700 and 6,000 mm/k.y.

• OSTI ID: 7061360
• Report Number(s): CONF-900605--
• Conference Information: Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (USA) Journal Volume: 74:5
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
ALKALINE EARTH METAL COMPOUNDS
BAHAMA ISLANDS
CALCITE
CALCIUM CARBONATES
CALCIUM COMPOUNDS
CARBON COMPOUNDS
CARBONATE MINERALS
CARBONATE ROCKS
CARBONATES
DEPOSITION
DEVELOPING COUNTRIES
GREATER ANTILLES
ISLANDS
JAMAICA
MINERALS
OXYGEN COMPOUNDS
ROCKS
SEDIMENTARY ROCKS
SEDIMENTATION
WEST INDIES