Abstract
Assessing Caribbean climate variability from Jamaican speleothems
Abstracts with programs - Geological Society of America, Vol.32(7), pp.94-95
Geological Society of America, 2000 annual meeting
2000
Abstract
Because the Caribbean climate is controlled by the interaction of the North Atlantic subtropical high sea level pressure (SLP) system and the eastern Pacific intertropical convergence zone (ITCZ), high-resolution paleoclimatic/paleoenvironmental reconstructions can greatly improve our understanding of century to millennia scale variability in these systems. Jamaica, two-thirds covered by karsted limestone and located in the north-central portion of the Caribbean, is an ideal site to utilize speleothem (secondary carbonate cave deposits) based paleoclimatic/paleoenvironmental reconstructions to improve our understanding of long-term climatic variability in the Caribbean. Fluctuations in SLP between the eastern Pacific and the tropical Atlantic result in changes in sea surface temperature (SST) of the Caribbean and rainfall variability. This variability should cause changes in vegetation activity and rainfall delta (super 18) O, and should be recorded in stalagmite delta (super 13) C and delta (super 18) O compositions. We have collected stalagmites from two Jamaican caves, one in the central mountainous region and one at the west coast. Carbon isotopic excursions in the two stalagmites from these two caves imply shifts in vegetation activity controlled by soil moisture content at the cave surface. The west coast cave, lying in the rain shadow region, exhibits major shifts in delta (super 13) C (6 to 8 per mil) suggesting major increases in C4 activity and reduced C3 contribution during drier periods. In the mountainous region, the shifts in delta (super 13) C are less pronounced (1 to 3 per mil) suggesting only minimal increases in C4 vegetation activity. Stalagmite delta (super 18) O long-term excursions (decades to centuries) in both the coastal and mountain caves are similar in magnitude (1 to 2 per mil). However, the coastal region stalagmites contain more short-lived excursions (1 to 5 year duration), suggesting greater sensitivity to storms/hurricanes (negative excursions), and pre-infiltration evaporative effects (positive excursions). High-resolution mass spectrometry dating and annual growth band counting is underway to improve chronology of samples.
Details
- Title: Subtitle
- Assessing Caribbean climate variability from Jamaican speleothems
- Creators
- Roger B Gomez - University of Iowa, Department of Geoscience Iowa City, IA USA United StatesLuis A GonzalezYemane AsmeromMark K Reagan
- Resource Type
- Abstract
- Publication Details
- Abstracts with programs - Geological Society of America, Vol.32(7), pp.94-95
- Conference
- Geological Society of America, 2000 annual meeting
- Publisher
- Geological Society of America (GSA)
- ISSN
- 0016-7592
- Alternative title
- Geological Society of America, 2000 annual meeting
- Language
- English
- Date published
- 2000
- Academic Unit
- Earth and Environmental Sciences
- Record Identifier
- 9984240800302771
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