The deglaciation over Laurentian Fan: History of diatoms, IRD, ice and fresh water | - CCMAR -

Journal Article

TítuloThe deglaciation over Laurentian Fan: History of diatoms, IRD, ice and fresh water
Publication TypeJournal Article
AuthorsGil, IM, Keigwin, LD, Abrantes, F
Year of Publication2015
JournalQuaternary Science Reviews
Date PublishedJan-12-2015
Pagination57 - 67
Palavras-chaveDeglaciation; Sea-ice; North atlantic; Diatom; Heinrich event 1; Younger Dryas; Bølling-Allerød; Older Dryas; Preboreal

A high-resolution diatom census coupled with other proxy data from Laurentian Fan (LF) provides a detailed description of the last deglaciation, bringing new insight to that period by revealing directly the timing of sea-ice formation and melting. Cold events Heinrich Event 1 (H1) and the Younger Dryas (YD) were multiphase events. H1 (∼16.8–15.7 cal kyr BP) was defined by a two-pulse release of icebergs promoting sea-ice formation. Melting of sea-ice after H1 corresponds to a cold and fresh anomaly that may have kept the Bølling colder than the Allerød. At ∼13.6 cal kyr BP, a cooling trend culminated with sea-ice formation, marking the YD onset (∼12.8 cal kyr BP). The decrease in sea-ice (∼12.2 cal kyr BP) led to a YD second phase characterized by very cold winters. However, the contribution of warm water diatoms tends to increase at the same time and the YD gradual end (∼11.6 cal kyr BP) contrasts with its abrupt end in Greenland ice cores. The YD cannot be regarded as an event triggered by a fresh water input through the Laurentian Channel since only one weak brief input nearly 1000 yrs after its onset is recorded. Very cold and cool conditions without ice mark the following Preboreal. A northward heat flux between 10.8 and 10.2 cal kyr BP was interrupted by the increased influence of coastal waters likely fed by inland melting. There was no further development of sea-ice or ice-drift then.

Short TitleQuaternary Science Reviews
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