Holocene changes in monsoon precipitation in the Andes of NE Perubased on δ18O speleothem records
Abstract
Two high resolution δ18O- speleothem records from Shatuca cave, situated at a mid-altitude location (1960 m asl) in the northeastern Peruvian Andes, were used to reconstruct the South American Summer Monsoon region (SASM) variability throughout the Holocene. The records show a long-term trend toward wetter conditions, in parallel with the austral summer insolation increase modulated by the precession cycle. In addition, abrupt multidecadal and multicentennial changes toward lower and higher isotopic values, some of them not previously reported, were observed throughout the Holocene and seem to have been felt on other Andean regions from different altitudes. Some of the changes toward wetter conditions were likely associated to sea surface temperatures during Bond events in the North Atlantic region, while some of the changes toward drier conditions were synchronous with dry period in previous Andean records, and seem to interrupt the long-term trend toward wetter conditions of the Holocene. The most enriched isotopic values- indicative of dry conditions- were recorded during the early Holocene, although some wet periods were also felt at this time period. At 5ky BP, a series of abrupt events marks the middle Holocene, as a period of extreme hydroclimatic changes that seems to occur at several regions on the Andes, probably related to Bond 4. The late Holocene is characterized by the most depleted isotopic values, but also by a change to a flatter trend that seems to be associated to a change in the austral summer insolation.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFMPP24A..08B
- Keywords:
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- 1616 Climate variability;
- GLOBAL CHANGEDE: 1630 Impacts of global change;
- GLOBAL CHANGEDE: 1637 Regional climate change;
- GLOBAL CHANGEDE: 1655 Water cycles;
- GLOBAL CHANGE