Heterozoan or foramol production is typical in extratropical carbonate sedimentary systems. However, under mesotrophic to eutrophic conditions, heterozoan carbonates also form in tropical settings, but such heterozoan tropical sedimentary systems are poorly understood. Nevertheless, distinction between tropical and extratropical heterozoan carbonates in ancient successions is crucial for accurate paleoenvironmental and paleoclimate reconstructions. Here, surficial Holocene and Pleistocene sediments of the northern Mauritanian shelf are studied as an example of a tropical eutrophic carbonate depositional system (11 µg·L−1 Chl-a [chlorophyll-a]). Upwelling nutrient-rich waters push onto the wide Mauritanian shelf, where they can warm up to in excess of 25°C. This condition favors production of heterozoan carbonates dominated by bivalves and foraminifers, even in this tropical setting. In addition, sediments are provided by eolian input from the desertic hinterland. The resulting sediments are carbonate and mixed carbonate–siliciclastic facies, in which the carbonates are characterized by a mixture of tropical and cosmopolitan taxa. Benthic photosynthetic biota are absent while suspension-feeding organisms are dominant. This foramol grain association on a shelf scale is reminiscent of cool-water carbonates, therefore recognition of warm-water heterozoan carbonates relies on key taxa related to tropical waters within the biota assemblages associated with a highly productive environment.
Michel J., Vicens G.M. and Westphal H. (2011) Modern Heterozoan Carbonates from A Eutrophic Tropical Shelf (Mauritania). Journal of Sedimentary Research 81(9): 641-655. 10.2110/jsr.2011.53
@article{Michel2011,
Title = {Modern Heterozoan Carbonates from A Eutrophic Tropical Shelf (Mauritania)},
Author = {Michel, J. and Vicens, G. M. and Westphal, Hildegard},
Editor = {},
Journal = {Journal of Sedimentary Research},
Year = {2011},
Pages = {641-655},
Volume = {81},
Doi = {10.2110/jsr.2011.53},
Abstract = {Heterozoan or foramol production is typical in extratropical carbonate sedimentary systems. However, under mesotrophic to eutrophic conditions, heterozoan carbonates also form in tropical settings, but such heterozoan tropical sedimentary systems are poorly understood. Nevertheless, distinction between tropical and extratropical heterozoan carbonates in ancient successions is crucial for accurate paleoenvironmental and paleoclimate reconstructions. Here, surficial Holocene and Pleistocene sediments of the northern Mauritanian shelf are studied as an example of a tropical eutrophic carbonate depositional system (11 µg·L−1 Chl-a [chlorophyll-a]). Upwelling nutrient-rich waters push onto the wide Mauritanian shelf, where they can warm up to in excess of 25°C. This condition favors production of heterozoan carbonates dominated by bivalves and foraminifers, even in this tropical setting. In addition, sediments are provided by eolian input from the desertic hinterland. The resulting sediments are carbonate and mixed carbonate–siliciclastic facies, in which the carbonates are characterized by a mixture of tropical and cosmopolitan taxa. Benthic photosynthetic biota are absent while suspension-feeding organisms are dominant. This foramol grain association on a shelf scale is reminiscent of cool-water carbonates, therefore recognition of warm-water heterozoan carbonates relies on key taxa related to tropical waters within the biota assemblages associated with a highly productive environment.},
}
TY - JOUR
AU - Michel, J.
AU - Vicens, G. M.
AU - Westphal, Hildegard
TI - Modern Heterozoan Carbonates from A Eutrophic Tropical Shelf (Mauritania)
T2 - Journal of Sedimentary Research
PY - 2011
SP - 641-655
VL - 81
DO - 10.2110/jsr.2011.53
AB - Heterozoan or foramol production is typical in extratropical carbonate sedimentary systems. However, under mesotrophic to eutrophic conditions, heterozoan carbonates also form in tropical settings, but such heterozoan tropical sedimentary systems are poorly understood. Nevertheless, distinction between tropical and extratropical heterozoan carbonates in ancient successions is crucial for accurate paleoenvironmental and paleoclimate reconstructions. Here, surficial Holocene and Pleistocene sediments of the northern Mauritanian shelf are studied as an example of a tropical eutrophic carbonate depositional system (11 µg·L−1 Chl-a [chlorophyll-a]). Upwelling nutrient-rich waters push onto the wide Mauritanian shelf, where they can warm up to in excess of 25°C. This condition favors production of heterozoan carbonates dominated by bivalves and foraminifers, even in this tropical setting. In addition, sediments are provided by eolian input from the desertic hinterland. The resulting sediments are carbonate and mixed carbonate–siliciclastic facies, in which the carbonates are characterized by a mixture of tropical and cosmopolitan taxa. Benthic photosynthetic biota are absent while suspension-feeding organisms are dominant. This foramol grain association on a shelf scale is reminiscent of cool-water carbonates, therefore recognition of warm-water heterozoan carbonates relies on key taxa related to tropical waters within the biota assemblages associated with a highly productive environment.
ER -
