Paleoclima do Centro-Oeste do Brasil desde o último período glacial com base em registros isotópicos de espeleotemas

Sponge spicule and phytolith evidence for Late Quaternary environmental changes in the tropical Pantanal wetlands of western Brazil

“…The late Holocene hiatus was non-depositional and most likely driven by subaerial exposure of LN during a prolonged interval of drought, which has been observed in other paleoenvironmental archives from central Pantanal (McGlue et al, 2012). Whitney et al, 2011;McGlue et al, 2012;Metcalfe et al, 2014) plotted against (B) δ 18 O records from caves (Novello et al, 2017;Novello, 2016).…”

“…We interpret that wet climatic conditions during Units I and III allowed riverine flooding and potentially avulsions to influence the LN floodplain. Some of the best late Pleistocene paleo-precipitation data available for the Pantanal comes from Jaraguá cave speleothem δ 18 O, which provide a proxy for monsoon strength (Novello, 2016;Novello et al, 2017). These datasets confirm that the monsoon was strong during the last glacial period (~27.9-17.8 kyr BP), Heinrich Stadial 1 (~17.7-14.8 kyr BP), and the Younger Dryas (12.9-11.6 kyr BP).…”

“…Yet a paucity of growth bands in stalagmites from Mato Grosso do Sul suggested limited water availability between 3800 and 2500 yr BP (Bertaux et al, 2002). Most recently, stalagmites from Jaraguá cave provides compelling evidence for dry conditions ~3670-2170 yr BP, when stalagmite growth halted entirely (Novello, 2016). Given the robust dating associated with the Jaraguá cave record, we suggest that a prolonged drought at the transition to the late Holocene was most likely, and that this event desiccated LN.…”

“…Regional comparison of our data with paleo-records from elsewhere in the Pantanal wetlands of Brazil. (A) Data from floodplain lakes in central Pantanal (Lakes Negra and Gaíva;Whitney et al, 2011;McGlue et al, 2012;Metcalfe et al, 2014) plotted against (B) δ 18 O records from caves(Novello et al, 2017;Novello, 2016).…”