Quaternary morphology and paleoenvironmental records of carbonate islands

Here I use a simple numerical model of reef profile evolution to show that the present-day morphology of carbonate islands has developed largely in response to late Pleistocene sea level oscillations in addition to variable vertical motion and reef accretion rates. In particular, large amplitude 'ice-house' sea-level variability resulted in long lagoonal depositional hiatuses, producing the morphology characteristic of modern-day barrier reefs. Reactivation of carbonate factories, transport of coarse reef material and rapid infilling of shallow water accommodation space since deglaciation makes these unique sites for reconstructing Holocene climate. Integration of new tropical cyclone reconstructions from both back-barrier reef (central Pacific) and carbonate bank (the Bahamas) settings with existing storm archives suggests a coordinated pattern of cyclone activity across storm basins since the late Holocene. Seesawing of intense tropical cyclone activity between the western Pacific (-0- 1000 yrs BP) and North Atlantic/Central Pacific (~1000 ~2500 yrs BP) appears closely tied with hydrographic patterns in the tropical Pacific and El Niflo-like variability. Decoupling of North Atlantic (inactive) and South Pacific (active) tropical cyclone patterns during the mid-Holocene suggests precession driven changes in storm season insolation may constrain ocean-atmosphere thermal gradients and therefore cyclone potential intensity on orbital timescales.

Department dc:contributor.department

Joint Program in Marine Geology and Geophysics

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2014

Author dc:creator

• Toomey, Michael (Michael Ryan)

Advisor dc:contributor.advisor

• Jeffrey Donnelly.

• Joint Program in Marine Geology and Geophysics.
• Earth, Atmospheric, and Planetary Sciences.
• Woods Hole Oceanographic Institution.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/87508

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/87508