Caribbean carbonate crash in pedro channel at subthermoclinal depth during marine isotope stage 11: A case of basin-to-shelf carbonate fractionation?

K. E. Zeigler, J. P. Schwartz, A. W. Droxler, M. C. Shearer, L. Peterson

Research output: Chapter in Book/Report/Conference proceedingChapter

4 Scopus citations


During the mid-Brunhes, interglacial marine isotope stage 11 (MIS-11) is represented in the Caribbean Basins by a 25 to as much as 40 ky-long interval characterized by intense carbonate dissolution from subthermoclinal to abyssal depths. This study focuses on the analysis of an 11 m-long piston core, PC-42, collected in Pedro Channel on the central part of the northern Nicaragua Rise at 903 m water depth. The intensity of dissolution was estimated using a series of different proxies: variations in Mg calcite content within the fine sediment fraction, variations in pteropod (aragonite) abundance, and variations in the average mass of Globigerinoides sacculifer specimens without their final sac (calcite). All proxies agree that sediments deposited during MIS-11 were affected by unusually intense dissolution. The interval lasted for a minimum of 25 ky (411 ky -384 ky) and a maximum of 40 ky (420 ky- 380 ky) and was characterized by little variability within that span. Previous explanations of increased carbonate dissolution in the modern interglacial Caribbean and the previous peak interglacial, MIS-5e, have focused on entrainment at subthermoclinal and intermediate depths of corrosive and nutrient-depleted Antarctic Intermediate Water (AAIW) characterized by light δ13C values. During MIS-11 in core PC-42, the benthic δ13C values obtained from Cibicidoides wuellerstorfl range from 1.2 to 1.4 parts per mil. Unexpectedly, this narrow range of δ13C values, unusually heavy relative to the late Brunhes interglacial stages, is identical to the range of values observed during glacial MIS-2, -3, and 4, when carbonate preservation was at its maximum during the last glacial/interglacial cycle. The range of heavy δ13C values observed during MIS-11, therefore, does not support a model of MIS-11 maximum dissolution generated by entrainment of light δ13C, corrosive intermediate waters entering the Caribbean. As an alternative to being circulation-driven (basin-to-basin fractionation), the maximum carbonate dissolution interval of MIS-11 can be better explained by an overall reduction of the carbonate ion concentration in the ocean, linked to the contemporaneous storage of large volumes of calcium carbonate within the global shallow water carbonate system, including coral reefs, carbonate banks, and platforms (basin-to-shelf fractionation).

Original languageEnglish (US)
Title of host publicationEarth?s Climate and Orbital Eccentricity
Subtitle of host publicationThe Marine Isotope Stage 11 Question, 2003
EditorsLloyd H. Burckle, Andre W. Droxler, Richard Z. Poore
PublisherBlackwell Publishing Ltd
Number of pages24
ISBN (Electronic)9781118668498
ISBN (Print)9780875909967
StatePublished - 2003

Publication series

NameGeophysical Monograph Series
ISSN (Print)0065-8448
ISSN (Electronic)2328-8779

ASJC Scopus subject areas

  • Geophysics


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