Abstract
The controls that affect the structure and timing of terminations are still poorly understood. We studied a tufa deposit from the Iberian Peninsula that covers Termination II (T-II) and whose chronology was synchronized to speleothem records. We used the same chronology to synchronize ocean sediments from the North Atlantic to correlate major climate events in a common timescale. We identify two stages within T-II. The first stage started with the increase of boreal summer integrated solar insolation, and during this stage three millennial climate oscillations were recorded. These oscillations resulted from complex ocean–atmosphere interactions in the Nordic seas, caused by the progressive decay of Northern Hemisphere ice-sheets. The second stage commenced after a glacial outburst that caused the collapse of the Thermohaline Circulation, a massive Heinrich event, and the onset of the Bipolar Seesaw Mechanism (BSM) that eventually permitted the completion of T-II. The pace of the millennial oscillations during the first stage of T-II controlled the onset of the second stage, when the termination became a non-reversible and global phenomenon that accelerated the deglaciation. During the last the two terminations, the BSM was triggered by different detailed climate interactions, which suggests the occurrence of different modes of terminations.
Highlights
The controls that affect the structure and timing of terminations are still poorly understood
The aim of this study is to describe a sequence of events and the mechanisms that controlled the structure and timing of the complete Termination II (T-II) by integrating the evidence from the Nordic Seas and the North Atlantic, along with their influence in the Mediterranean r egion[8,10,11], with the response of the Southern Hemisphere once the Bipolar Seesaw Mechanism (BSM) was activated[5,12]
The second stage of T-II was initiated along with the large Heinrich event Heinrich event 11 (H11) that coincides with an outburst of proglacial lakes from North America that triggered the BSM and initiated the deglaciation in the Southern Hemisphere
Summary
The controls that affect the structure and timing of terminations are still poorly understood. The first stage started with the increase of boreal summer integrated solar insolation, and during this stage three millennial climate oscillations were recorded. These oscillations resulted from complex ocean–atmosphere interactions in the Nordic seas, caused by the progressive decay of Northern Hemisphere ice-sheets. The aim of this study is to describe a sequence of events and the mechanisms that controlled the structure and timing of the complete T-II by integrating the evidence from the Nordic Seas and the North Atlantic, along with their influence in the Mediterranean r egion[8,10,11], with the response of the Southern Hemisphere once the BSM was activated[5,12]
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have