Evolution of the northern Nicaragua Rise during the Oligocene-Miocene; drowning by environmental factors

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doi: 10.1016/j.sedgeo.2004.12.028
Author(s): Mutti, Maria; Droxler, André W.; Cunningham, Andrew D.
Author Affiliation(s): Primary:
Universität Potsdam, Institut für Geowissenschaften, Potsdam, Federal Republic of Germany
Vrije Universiteit, Netherlands
Rice University, United States
BP Amoco, United States
Volume Title: Sedimentology in the 21st Century; a tribute to Wolfgang Schlager
Volume Author(s): Reijmer, John J. G., editor; Immenhauser, Adrian
Source: Sedimentology in the 21st Century; a tribute to Wolfgang Schlager, edited by John J. G. Reijmer and Adrian Immenhauser. Sedimentary Geology, 175(1-4), p.237-258. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0037-0738 CODEN: SEGEBX
Note: In English. 62 refs.; illus., incl. sects., geol. sketch maps
Summary: Possible causes to explain platform drowning have been hotly debated by carbonate sedimentologists for more than a decade now. In this paper, we present multiple evidence to explain the drowning of a carbonate megabank that covered most of the modern Northern Nicaragua Rise (NNR) during an interval spanning from late Oligocene to early Miocene by the interaction of several environmental factors. The recovery during ODP Leg 165 of late Oligocene to middle Miocene sedimentary sequences in the sub-seafloor of the modern channels and basin, Pedro Channel and Walton Basin, respectively, that dissect the NNR (Site 1000) and south of the rise in the Colombian Basin (Site 999), combined with information from dredged rock samples, allows us to explore in more detail the timing and possible mechanisms responsible for the drowning of the megabank and its relationship to Miocene climate change. The modern system of isolated banks and shelves dissected by a series of intervening seaways and basins on the NNR has evolved from a continuous, shallow-water carbonate "megabank" that extended from the Honduras/Nicaraguan mainland to the modern island of Jamaica. Available information suggests that this megabank broke apart and partially drowned in the late part of the late Oligocene at around 27 Ma and finally foundered during the late early Miocene around 20 Ma, resulting in limited neritic coral growth in the areas where the modern isolated carbonate banks and shelves are occurring today. Available information also suggests that the southern and central parts of Pedro Channel were already a deep-water area before the major episode of platform drowning, and its formation predates the initiation of the Caribbean Current. However, after the partial drowning of the megabank, the channel has become a major pathway for the Caribbean Current. Stratigraphic units identified in deep-water carbonates sampled at ODP Sites 999 and 1000 help to constrain the environmental setting leading to the drowning of the banks. Changes in lithology and mass accumulation rates of both the carbonate and non-carbonate fraction parallel stable isotope shifts and likely indicate regional changes in climate and circulation during the late Oligocene-middle Miocene interval. Carbonate mass accumulation rates (MARs) at Site 999 suggest increased regional productivity during the early Miocene. Terrigenous MARs at both Sites 999 and 1000 show a general increase from the Burdigalian through the Serravallian. The temporal association among episodes of neritic platform deposition, followed by increased productivity as identified by higher carbonate MARs and positive excursion in carbon isotopes, suggests that oceanographic changes such as local upwelling and nutrification have led to the partial drowning of the NNR "megabank". Abstract Copyright (2005) Elsevier, B.V.
Year of Publication: 2005
Research Program: ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Atlantic Ocean; Biogenic structures; Biostratigraphy; C-13/C-12; Carbon; Carbonate banks; Caribbean Sea; Cenozoic; Chemostratigraphy; Climate change; Correlation; Foraminifera; Geophysical methods; Geophysical profiles; Geophysical surveys; Invertebrata; Isotope ratios; Isotopes; Leg 165; Lithostratigraphy; Microfossils; Miocene; Neogene; Nicaragua Rise; North Atlantic; O-18/O-16; ODP Site 1000; ODP Site 999; Ocean Drilling Program; Oligocene; Oxygen; Paleo-oceanography; Paleoclimatology; Paleogene; Protista; Sea-level changes; Sedimentary structures; Seismic methods; Seismic profiles; Stable isotopes; Surveys; Tertiary; Unconformities
Coordinates: N124437 N124437 W0784422 W0784422
N163313 N163313 W0795200 W0795200
Record ID: 2006020735
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands