Chapter 16 - Full and Late Glacial Lake Records Along the PEP 1 Transect: Their Role in Developing Interhemispheric Paleoclimate Interactions

Abstract

Lacustrine records that encompass the full, and late glacial periods, extends into the early Holocene document climate changes through the effects on limnology. Wind intensity, temperature, and water balance are the principal climate effects recorded by lake sediments. A selection of lake records along the Pole-Equator-Pole: Americas transect from Alaska to southern Patagonia reveals broad zonal regions of climate-controlled paleolimnology. In the Arctic, lakes record climate mostly as temperature signals that change the effective moisture balance, and their productivity. South of the Laurentide ice sheet, lakes also responded to warming temperatures, and reduced anticyclonic wind systems between the full glacial, and the early Holocene. A related effect, the disruption of Intertropical Convergence Zone (ITCZ), and the moisture-bearing trade winds responsible for maintaining lakes in Central America, and northern South America, caused basins in this region to be shallow, saline, or dry during the full glacial period, and to become re-established only by the latest glacial, and early Holocene. The single site in southern South America apparently did not receive moisture in significant amounts until the early Holocene, as westerly precipitation finally became established in the region. This analysis indicates that lakes recorded generally synchronous climate changes by similar but sometimes opposite responses. This synchroneity does not imply the same causality, even though the dynamics of climate change between the full glacial and the Holocene were clearly linked and mutually interdependent.