Neoglaciation in the Spanish Pyrenees: a multiproxy challenge

Following the Holocene Thermal Maximum, dated between 11 and 6 ka, the Neoglacial period was one of the progressive, fluctuating cooling that peaked during the Little Ice Age (LIA). The almost total absence of glacial tills prior to the LIA in the Pyrenees forces recourse to a high variety of proxies, including lacustrine sediments, palynological records, dendroclimatology, ice cores from glaciers and caves, speleothems, historical documentation and glacial records. This has enabled us to identify several colder periods during the mid- and late-Holocene: (i) the first phase of the Neoglacial period occurred at some time around 6 ka; (ii) a glacial pulse immediately before 3.4 ka; (iii) a glacial re-advance during the Dark Ages, i.e., immediately before the Medieval Climate Anomaly, between the fourth and ninth centuries; and (iv) the Little Ice Age, which started at the beginning of the fourteenth century and finished in the mid-nineteenth century. During the LIA, there was remarkable climate variability, with two, and probably three, glacial pulses, mainly between 1620 and 1715 and in the first half of the nineteenth century. Of all of the Holocene cold periods, most of the European paleoclimatic records coincide on the occurrence of the LIA. For the remaining Holocene cold periods, European records show high variability and uncertainty, particularly for the onset of the Neoglacial, although the phases of glacial pulses in the Pyrenees broadly coincide with those identified in the Alps and northern Europe.