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Timing and structure of Mega‐SACZ events during Heinrich Stadial 1
Author(s) -
Stríkis Nicolás M.,
Chiessi Cristiano M.,
Cruz Francisco W.,
Vuille Mathias,
Cheng Hai,
Souza Barreto Eline A.,
Mollenhauer Gesine,
Kasten Sabine,
Karmann Ivo,
Edwards R. Lawrence,
Bernal Juan Pablo,
Sales Hamilton dos Reis
Publication year - 2015
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2015gl064048
Subject(s) - stadial , geology , speleothem , climatology , monsoon , precipitation , oceanography , geography , holocene , archaeology , meteorology , cave
Abstract A substantial strengthening of the South American monsoon system (SAMS) during Heinrich Stadials (HS) points toward decreased cross‐equatorial heat transport as the main driver of monsoonal hydroclimate variability at millennial time scales. In order to better constrain the exact timing and internal structure of HS1 over tropical South America, we assessed two precisely dated speleothem records from central‐eastern and northeastern Brazil in combination with two marine records of terrestrial organic and inorganic matter input into the western equatorial Atlantic. During HS1, we recognize at least two events of widespread intensification of the SAMS across the entire region influenced by the South Atlantic Convergence Zone (SACZ) at 16.11–14.69 kyr B.P. and 18.1–16.66 kyr B.P. (labeled as HS1a and HS1c, respectively), separated by a dry excursion from 16.66 to 16.11 kyr B.P. (HS1b). In view of the spatial structure of precipitation anomalies, the widespread increase of monsoon precipitation over the SACZ domain was termed “Mega‐SACZ.”