Abstract
Summary Accumulation variations of the calcareous nannofossil genus Discoaster have been determined from a high latitude North Atlantic sediment sequence (DSDP Hole 552A) of late Pliocene age. Spectral analysis for the preglacial Pliocene reveals a dominant quasiperiodicity associated with obliquity-induced temperature variations in surface water. Spectral peaks corresponding to the 100 Kyr eccentricity and the 21 Kyr precession periodicities are also detected. Coarse fraction analysis of core V26-145 (Blake Plateau) illustrates the Pliocene development of an increasingly intense subtropical circulation in the North Atlantic. A trend towards increased current velocity occurs through the early Pliocene and probably reflects the progressive emergence of the Panamanian Isthmus, and concomitant intensification of surface water circulation of the North Atlantic subtropical gyre system. In the Rockall Plateau area (Hole 552A), however, no evidence is seen for a related surface water warming. Discoaster accumulation data indicate that the preglacial Pliocene development of surface water temperature in the high latitude North Atlantic reflects a progressive climatic deterioration.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
