Leeward vs windward effects on glacial/interglacial periplatform aragonite cycles off Pedro Bank and Jamaica (northern Nicaragua rise)

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

OSTI ID:7061084

Glaser, K S; Droxler, A W; Haddad, G A ^[1]

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

Fine (< 62 {mu}m) aragonite content in periplatform sediment from the northern (leeward) and southern (windward) slopes of Pedro Bank shows late Quaternary climate-induced cyclic downcore variations. Intervals characterized by high aragonite content correspond to interglacial stages. The aragonite cycles are clearly developed despite significant windward/leeward differences in sediment sources and composition, pelagic productivity( ), and current regime. Interglacial sedimentation rates on the leeward slope (LS) are nearly twice as high as those on the windward slope (WS), and twice as high as LS glacial sedimentation rates. Carbonate values (75-85%) in sediments deposited on the northern slope of Pedro Bank are higher than those (50-70%) on its southern slope. On both slopes, high carbonate values correspond to interglacial intervals. The lowest carbonate values occur during glacial intervals on the southern slope and are explained by an increase of siliciclastic input from Jamaica during sea level lowstands. This siliciclastic increase could compensate for the drop of bank-derived fine aragonite, and thus, could explain the constant glacial/interglacial sedimentation rates found on the southern slope. In addition, high pteropod abundance during glacial stages along the southern slope may also indicate higher glacial pelagic productivity. Winnowing effects are rather conspicuous in one core from the northern slope within Walton basin (600 m water depth) during glacial intervals, when values of the coarse (> 62 {mu}m) fraction are the highest (the opposite is observed in the other cores). In this relatively shallow core, partial cementation during glacial intervals is also observed.

• OSTI ID: 7061084
• 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
CALCITE
CALCIUM CARBONATES
CALCIUM COMPOUNDS
CARBON COMPOUNDS
CARBONATE MINERALS
CARBONATE ROCKS
CARBONATES
DEPOSITION
DEVELOPING COUNTRIES
DIAGENESIS
GEOLOGIC STRUCTURES
GREATER ANTILLES
ISLANDS
JAMAICA
MINERALS
OXYGEN COMPOUNDS
ROCKS
SEDIMENTARY BASINS
SEDIMENTARY ROCKS
WEST INDIES