The deglaciation of the Americas during the Last Glacial Termination

PALACIOS, DAVID; STOKES, CHRIS R.; PHILLIPS, FRED M.; CLAGUE, JOHN J.; ALCALÁ-REYGOSA, JESUS; ANDRÉS, NURIA; ANGEL, ISANDRA; BLARD, PIERRE-HENRI; BRINER, JASON P.; HALL, BRENDA L.; DAHMS, DENNIS; HEIN, ANDREW S.; JOMELLI, VINCENT; MARK, BRYAN G.; MARTINI, MATEO A.; MORENO, PATRICIO; RIEDEL, JON; SAGREDO, ESTEBAN; STANSELL, NATHAN D.; VÁZQUEZ-SELEM, LORENZO; VUILLE, MATHIAS; WARD, DYLAN J.

EARTH-SCIENCE REVIEWS

ELSEVIER SCIENCE BV

Año: 2020 vol. 203

0012-8252

This paper reviews current understanding ofdeglaciation in North, Central and South America from the Last Glacial Maximumto the beginning of the Holocene. Together with paleoclimatic andpaleoceanographic data, we compare and contrast the pace of deglaciation andthe response of glaciers to major climate events. During the Global LastGlacial Maximum (GLGM, 26.5-19 ka), average temperatures decreased 4º to 8ºC inthe Americas, but precipitation varied strongly throughout this large region.Many glaciers in North and Central America achieved their maximum extent duringthe GLGM, whereas others advanced even farther during the subsequent HeinrichStadial 1 (HS-1). Glaciers in the Andes also expanded during the GLGM, but thatadvance was not the largest, except on Tierra del Fuego. HS-1 (17.5-14.6 ka)was a time of general glacier thickening and advance throughout most of Northand Central America, and in the tropical Andes; however, glaciers in thetemperate and subpolar Andes thinned and retreated during this period. Duringthe Bølling-Allerød interstadial (B-A, 14.6-12.9 ka), glaciers retreatedthroughout North and Central America and, in some cases, completelydisappeared. Many glaciers advanced during the Antarctic Cold Reversal (ACR,14.6-12.9 ka) in the tropical Andes and Patagonia. There were small advances ofglaciers in North America, Central America and in northern South America(Venezuela) during the Younger Dryas (12.9-11.7 ka), but glaciers in centraland southern South America retreated during this period, except on theAltiplano where advances were driven by an increase in precipitation. Takentogether, we suggest that there was a climate compensation effect, or ?seesaw?,between the hemispheres, which affected not only marine currents andatmospheric circulation, but also the behavior of glaciers. This seesaw isconsistent with the opposing behavior of many glaciers in the Northern andSouthern Hemispheres.