Open AccessEvidence of central Alpine glacier advances during the Younger Dryas–early Holocene transition period
Author(s) -
Moran Andrew P.,
IvyOchs Susan,
Schuh Michael,
Christl Markus,
Kerschner Hanns
Publication year - 2016
Publication title -
boreas
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.95
H-Index - 74
eISSN - 1502-3885
pISSN - 0300-9483
DOI - 10.1111/bor.12170
Subject(s) - younger dryas , cirque , holocene , geology , moraine , cirque glacier , deglaciation , glacier , physical geography , allerød oscillation , climate change , preboreal , surface exposure dating , period (music) , abrupt climate change , climatology , geomorphology , paleontology , global warming , geography , oceanography , cryosphere , effects of global warming , ice stream , sea ice , physics , acoustics
The transition phase from Lateglacial to Holocene climate conditions was accompanied by a pronounced reorganization of climate patterns in the Northern Hemisphere. Evidence of Alpine palaeoglaciers provides a basis for understanding climate downturns during a time of generally warming conditions. In this context a series of well‐preserved and previously undated moraines were investigated in the small Falgin cirque located in the central Alpine Langtaufers Valley (South Tyrol, Italy) and in the neighbouring Hinteres Bergle cirque of the Radurschl Valley (North Tyrol, Austria). Both localities are situated in the driest area of the eastern Alps. They lie well above prominent moraines associated with the Younger Dryas ( YD ) cold phase and represent the first moraines below Little Ice Age ( LIA ) positions. The corresponding equilibrium line altitude of the palaeoglaciers in both cirques was 100–120 m lower than during the LIA . Surface exposure dating ( 10 Be) of the inner Falgin moraines shows a mean stabilization age of 11.2±0.9 ka, which is similar to the deglaciation age of 10.9±0.8 ka for the Hinteres Bergle cirque. The ages indicate glacier activity most likely during the earliest Holocene or the YD /Holocene transition. These findings point to a climate with mean summer temperatures about 1.5 °C lower than during the 20th century in the Alps.