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vol.38 issue2THERMAL MATURATION STUDY OF KEROGEN IN THE COAL SEAMS OF THE GUADUAS FORMATION, EASTERN CORDILLERA (COLOMBIA), USING VITRINITE REFLECTANCE, ROCK EVAL PIROLISIS, NUCLEAR MAGNETIC RESONANCE AND PROXIMAL ANALYSISPHYSICAL ANALYSIS OF THE SPATIAL DISTRIBUTION OF HUMMOCKS FROM THE DEBRIS AVALANCHE LOCATED IN THE AREA OF NEREIDAS, WEST FLANK OF NEVADO DEL RUIZ VOLCANO author indexsubject indexarticles search
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Boletin de Geología

Print version ISSN 0120-0283

Abstract

PATARROYO, German D.  and  MARTINEZ, José I.. LATE HOLOCENE PALEOXYGENATION AND PALEOPRODRUCTIVITY OF THE PANAMA GULF. bol.geol. [online]. 2016, vol.38, n.2, pp.75-92. ISSN 0120-0283.  http://dx.doi.org/10.18273/revbol.v38n2-2016005.

Paleocenographic conditions in the Panama Bight for the past 4000 years were inferred by using the micropaleontological record from the deep sea core KNR176-2-MC4 (7.27°N, 78.24°W; water depth 2121 m). The epifauna-infauna relationship of deep-sea benthic foraminifera and their diversity gradually increase up-core, which is interpreted as a result of: (1) a decrease in the dissolved oxygen content towards the recent and, (2) higher taphonomic effects which modify the original composition of the microfauna. Indicative taxa of moderate oxygen conditions, such as Uvigerina proboscidea and Oridorsalis umbonatus were found at the base of the core. In contrast, lower oxygenation and higher productivity conditions are inferred by the common presence of Globobulimina affinis and Uvigerina proboscidea. Additional paleoproductivity indicators such as Epistominella spp. and Uvigerina peregrina were more common in the middle part of the core. The comparison of the MC4 core micropaleontological record with several paleoclimatic records from the Panama isthmus (the Woodhouse Lake, and the Chilibrillo stalagmite) illustrates that a higher recurrence of El Niño events since 5000 years BP, could be related to a higher frequency and intensity of upwelling processes in the Panama Gulf. However, the magnetic susceptibility of the MC4 core presents variations which cannot be related with to a reduction in local rainfall.

Keywords : deep sea benthic foraminifera; Panama basin; late Holocene; paleoceanography.

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