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Circulation through the Central American Seaway during the Miocene carbonate crash

Derrick R. Newkirk and Ellen E. Martin
Circulation through the Central American Seaway during the Miocene carbonate crash
Geology (Boulder) (January 2009) 37 (1): 87-90


Changes in circulation associated with the shoaling of the Isthmus of Panama and the Caribbean carbonate crash in the Miocene were investigated using Nd isotopes from fossil fish teeth and debris from two sites in the Caribbean Basin (Ocean Drilling Program Sites 998 and 999) and two sites in the eastern equatorial Pacific (Sites 846 and 1241). The total range for epsilon (sub Nd) values measured from 18 to 4.5 Ma in the Caribbean is -7.3 to 0. These values are higher than Atlantic water masses (approximately -11) and range up to values equivalent to contemporaneous Pacific water masses, confirming that flow into the Caribbean Basin was composed of a mixture of Pacific and Atlantic waters, with an upper limit of almost pure Pacific-sourced waters. Throughout the Caribbean record, particularly during the carbonate crash (10-12 Ma), low carbonate mass accumulation rates (MARs) correlate with more radiogenic epsilon (sub Nd) values, indicating increased flow of corrosive Pacific intermediate water into the Caribbean Basin during intervals of dissolution. This flow pattern agrees with results from general ocean circulation models designed to study the effect of the shoaling of the Central American Seaway. Low carbonate MARs and high epsilon (sub Nd) values also correlate with intervals of increased Northern Component Water production and, therefore, enhanced conveyor circulation, suggesting that the conveyor may respond to changes in circulation associated with shoaling of the Central American Seaway. Reduced Pacific throughflow related to shoaling of the seaway led to a gradual increase in carbonate preservation and more Atlantic-like epsilon (sub Nd) values following the carbonate crash.

ISSN: 0091-7613
EISSN: 1943-2682
Serial Title: Geology (Boulder)
Serial Volume: 37
Serial Issue: 1
Title: Circulation through the Central American Seaway during the Miocene carbonate crash
Affiliation: University of Florida, Department of Geological Sciences, Gainesville, FL, United States
Pages: 87-90
Published: 200901
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 34
Accession Number: 2009-020475
Categories: Stratigraphy
Document Type: Serial
Bibliographic Level: Analytic
Annotation: With GSA Data Repository Item 2009019
Illustration Description: illus. incl. sketch map
N19°29'23" - N19°29'23", W82°56'10" - W82°56'10"
N12°44'37" - N12°44'37", W78°44'22" - W78°44'22"
S03°05'49" - S03°05'41", W90°49'06" - W90°49'04"
N05°50'60" - N05°50'60", W86°27'00" - W86°27'00"
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 200912
Program Name: ODPOcean Drilling Program
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