The Huelmo–Mascardi Cold Reversal (HMCR) is a cooling event in

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sout ...

between 11,400 and 10,200 ¹⁴C years BP. This cooling began about 550 years before the

Younger Dryas The Younger Dryas (c. 12,900 to 11,700 years BP) was a return to glacial conditions which temporarily reversed the gradual climatic warming after the Last Glacial Maximum (LGM, c. 27,000 to 20,000 years BP). The Younger Dryas was the last stag ...

cooling in the Northern Hemisphere, and both periods ended at about the same time. The event was given its name from the Huelmo,

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...

, and Mascardi Lake,

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...

(

Nahuel Huapi National Park Nahuel Huapi National Park () is the oldest national park in Argentina, established in 1934. It surrounds Nahuel Huapi Lake in the foothills of the Patagonian Andes. The largest of the national parks in the region, it has an area of , or nearly ...

) sites where it was detected and dated. The HMCR cooling event began with the accentuation of a cooling period which began 12,400 ¹⁴C yr BP. The 11,400 ¹⁴C yr BP (13,400 calendar years BP) event onset took place 400–700 years before the onset of the Younger Dryas event. The 10,200 ¹⁴C yr BP (circa 11,500 cal yr BP) end date is difficult to calibrate to a calendar year because it took place during a radiocarbon age plateau. The end of the HMCR also marked the end of the cooling period.

References

* {{DEFAULTSORT:Huelmo Mascardi Cold Reversal Pleistocene events History of climate variability and change History of South America