OSL dating of Brazilian fluvial carbonates (tufas) using detrital quartz grains

Paleoenvironmental Evolution of Continental Carbonates in West-Central Brazil

“…Some studies in this area (Boggiani et al 1999, 1998, Corrêa et al 2011, Ribeiro et al 2015, Sallun Filho et al 2009b, Turcq et al 1987 were successful in dating the continental carbonates, providing 37 ages, ranging from more than 600.000 years before present (600 kyr BP) to 0.65 kyr BP (Table I In the Serra das Araras two facies of continental carbonates were recognized (Almeida 1954, Corrêa et al 2011: directly overlying the basement limestones there is a basal layer of conglomerates, described as pinkish micritic calcite conglomerate with quartz and limestone pebbles, and local occurrence of gastropods; a top layer of tufas directly overlying the basal conglomerate, described as tufas related with springs, cascades, pendants and perched springline types, rich in detrital components as well as in plant and gastropods remains. On the Corumbá/Ladário plateau two facies were recognized (Almeida 1945, Boggiani andCoimbra 1995): directly overlying the carbonate-rich basement; there is a basal layer of conglomerates, 0.5 to 9 m thick, described as polymictic conglomerate with a micritic matrix, and a layer of brecciated wackestone, 0.5 to 1 m thick, described as limestone rich in plant and shells remains.…”

“…Thus, it is possible to identify 2 sedimentary successions that are physically and stratigraphically disconnected. The chronology presented here (Table I) uses data from many regional papers (Boggiani et al 1998, Boggiani et al1999, Corrêa et al 2011, Ribeiro et al 2015, Sallun Filho et al 2009a, Turcq et al 1987.…”

Optically stimulated luminescence and isothermal thermoluminescence dating of high sensitivity and well bleached quartz from Brazilian sediments: from Late Holocene to beyond the Quaternary?

“…A loss or uptake of radionuclides, occurring after sediment deposition, negatively affects the dose rate over time, and leads to erroneous luminescence age. This is an issue of concern for dating of carbonate rich (Ribeiro et al 2015) or heavy weathered sediments. With radionuclides concentrations, we apply conversion factors to obtain a dose rate (Adamiec & Aitken 1998, Guérin et al 2011.…”

“…Luminescence dating studies in Brazil can be divided into three groups, which express an evolutionary methodological trend: the pioneer attempts with thermoluminescence in sediments from the Rio Grande do Sul coastal plain (Poupeau et al 1984(Poupeau et al , 1988; a second phase of thermoluminescence datings includes the first uses of OSL without the SAR protocol, mainly in coastal and/or eolian contexts (Suguio et al 1999, 2003, Barreto et al 2001, Giannini et al 2007, Tatumi et al 2008) but also in colluvium deposits (Sallun & Suguio 2010); and, lastly, the application of OSL-SAR to coastal, aeolian and fluvial deposits (Teeuw & Rhodes 2004, Sawakuchi et al 2008, Tsoar et al 2009, Soares et al 2010, Guedes et al 2011, Zular et al 2012, Ribeiro et al 2015 Figure 2. Dose response curve for a quartz aliquot.…”

“…In this paper, we present the basic principles of OSL dating, along with examples of OSL dating of Late Holocene to Late Pleistocene sediments from coastal and continental settings in Brazil. Study cases comprise the review of published OSL ages of coastal sediments (Zular et al 2012) and fluvial carbonate sediments (Ribeiro et al 2015), as well as new OSL data about fluvial sediments from the Pantanal wetland and Parnaíba River. Finally, we explored the potential of isothermal thermoluminescence (ITL) signals (Jain et al 2007, Vandenberghe et al 2009 in dating older Brazilian sediments from the Xingu River (eastern Amazonia).…”