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Huguet, C., Jaeschke, A. and Rethemeyer, J. (2022). Paleoclimatic and palaeoceanographic changes coupled to the Panama Isthmus closing (13-4 Ma) using organic proxies. Paleogeogr. Paleoclimatol. Paleoecol., 601. AMSTERDAM: ELSEVIER. ISSN 1872-616X

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Abstract

This study reconstructs the climatic and oceanographic changes from 13 to 4 Ma at Ocean Drilling Program (ODP) Sites 999 (Caribbean) and 1241 (East Pacific) during Panama Isthmus closure. We used lipid biomarkers as marine production indicators and organic proxies (U37K ' and TEX86H) to estimate ocean surface and thermocline temperatures. Enhanced terrestrial input during the first 3 Ma of the record, possibly coupled to tectonic pro-cesses, may have triggered higher surface productivity at both sides of the Isthmus. Even though marine pro-duction is generally higher in the tropical Pacific, a peak in alkenone production at 12.4-10.6 Ma indicates unrestricted inflow of nutrient-rich waters into the Caribbean. Higher production is observed during the global late Miocene biogenic bloom (LMBB 8-4.5 Ma) coupled to enhanced nutrients from terrestrial sources and/or upwelling. We find a good correspondence between U37K ' and modern sea surface temperature (SST). The TEX86H is a good tracer for thermocline values, however, the deeper Thaumarchaeota distribution in the Caribbean may result in an underestimation of absolute temperatures at ODP Site 999. None the less, temperature records at both Sites show similar trends coupled to global climate dynamics, therefore Isthmus build up did not signifi-cantly affect surface or thermocline temperatures at a regional level. Globally reported decreasing temperatures during the late Miocene and early Pliocene coupled to decreasing CO2 levels are registered at both Sites down to at least 200 m. The late Miocene warm period (LMWP 9.5-7 Ma), late Miocene cold period (LMC 7-5.4 Ma) and the Pliocene warm period (PWP 4-3.5 Ma) are reflected by our temperature records confirming global climate is the main driver of temperature evolution in the study area. The reconstructed temperatures are mainly coupled to atmospheric forcing in the Caribbean, with a deviation possibly due to inflow of colder Pacific intermediate waters. While at ODP Site 1241 temperatures are mainly controlled by global climate, the Site also reflects changes in the water column as it migrates interacting with the complex current structure of the tropical Pacific. Decoupled temperature patterns at both Sites are related with differential changes in water column structure partially masking the climatic signal. Therefore, we could establish that while tectonic processes and related terrestrial input increases as well as upwelling control production and water column structure, climate in the study area remained tuned to global patterns regardless of Isthmus closure stage.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Huguet, C. UNSPECIFIED UNSPECIFIED UNSPECIFIED Jaeschke, A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Rethemeyer, J. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-663598
DOI:	10.1016/j.palaeo.2022.111139
Journal or Publication Title:	Paleogeogr. Paleoclimatol. Paleoecol.
Volume:	601
Date:	2022
Publisher:	ELSEVIER
Place of Publication:	AMSTERDAM
ISSN:	1872-616X
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language SEA-SURFACE TEMPERATURE; CENTRAL-AMERICAN SEAWAY; ISOPRENOID TETRAETHER LIPIDS; LATE MIOCENE; CLIMATE; OCEAN; MARINE; CIRCULATION; CALIBRATION; ATLANTIC Multiple languages Geography, Physical; Geosciences, Multidisciplinary; Paleontology Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/66359