GLORIA

GEOMAR Library Ocean Research Information Access

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    facet.materialart.
    Unknown
    SEPM
    In:  Journal of Sedimentary Research, 81 (9). pp. 641-655.
    Publication Date: 2020-07-20
    Description: 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 mg?L21 Chl-a [chlorophyll-a]). Upwelling nutrient-rich waters push onto the wide Mauritanian shelf, where they can warm up to in excess of 25uC. 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.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 2
    Publication Date: 2023-09-19
    Description: Ecological and taxonomic study of the mollusk-rich fauna of the Golfe d'Arguin, North Mauritania, investigates the various environmental influences affecting this tropical shelf. The upwelling of nutrient-rich waters leads to a highly productive environment under tropical conditions. The resulting mixed carbonate-siliciclastic sediment contains a large portion of calcareous components produced by heterotrophic organisms-e.g., mollusks, foraminifers, worms, barnacles-that are reworked on the open shelf. On the basis of mollusk assemblages, six taphocoenoses are defined, all being characterized by a mixed fauna of tropical (e.g., Tellina densestriata), subtropical (e.g., Macoma cumana) and temperate (e.g., Spisula subtruncata) species. Differences between the assemblages are related to the medium-grain size ranging from mud to gravel-that results from local hydrodynamic conditions and water depth. Among carbonate grains, Donax burnupi shells are very abundant in the swell-exposed, northern part of the Golfe d'Arguin and reflect the tropical to subtropical, high-energy, and high-nutrient waters. Mollusk assemblages are demonstrated to be a sensitive tool for deciphering complex environmental conditions in sedimentary archives.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...