ESR dating of pleistocene mammal teeth and its implications for the biostratigraphy and geological evolution of the coastal plain, Rio Grande do Sul, southern Brazil

The sea-level highstand correlated to marine isotope stage (MIS) 7 in the coastal plain of the state of Rio Grande do Sul, Brazil

“…The results points to an age close to 235-238 ka for the shells (Lopes et al in press), an estimate consistent with the the TL ages obtained from the overlying sediments. The mammalian teeth provided ages between 80±10 ka and 42±3 ka, also consistent with the previous ESR datings (Lopes et al 2010).…”

“…Other records, however, correlate the highest peak to the event 7.3 (MIS 7c, Barreto et al 2002, Waelbroeck et al 2002, Suguio et al 2011 or to the event 7.1 (MIS 7a, Gallup et al 1994, Hearty and Kindler 1995, Goy et al 2006. The ESR age of ~226 ka BP from a tooth of the extinct mammal Toxodon collected from a Type 1 fluvial facies at the marine-terrestrial transition exposed along Chuí Creek (Lopes et al 2010) indicates that sea-level was already falling around this time, which would be consistent with the end of MIS 7e, around 228 ka BP (Robinson et al 2002). The absence of erosional features indicative of fluvial incision, which is expected if regional base level was lower than the fluvial system (Catuneanu 2006, Holz 2012), indicates that sea-level was still relatively high between 235 and 214 ka BP.…”

“…The absence of erosional features indicative of fluvial incision, which is expected if regional base level was lower than the fluvial system (Catuneanu 2006, Holz 2012), indicates that sea-level was still relatively high between 235 and 214 ka BP. The TL age obtained from the fossil-bearing aeolian sediments above the marine-terrestrial transition indicates that sea-level had fully retreated around ~214 ka BP, and around ~207 ka BP it was already below the present level, based on an ESR age of a mammalian tooth from the continental shelf (Lopes et al 2010). The TL age of ~173 ka BP from the dark sand lens, interpreted as a meandering fluvial system that incised the underlying marine facies due to lowered regional base level, is also consistent with an interval of lower sea-level.…”

High-Frequency Sequences in the Quaternary of Pelotas Basin (coastal plain): a record of degradational stacking as a function of longer-term base-level fall

“…These systems are interpreted to represent periods of high sea level, which Villwock and Tomazelli (1995) correlated to isotope stages 11, 9, 5 and 1, respectively. These correlations were confirmed for Systems III and IV by 14 C and thermoluminescence dating (Poupeau et al 1988;Tomazelli et al 1998;Buchmann & Tomazelli 2003;Dillenburg et al 2006,ore recent work indicated that System II was developed in response to transgression related to the oxygen isotope stage 7, instead of stage 9, based on thermoluminescence ages in quartzose deposits and electron spin resonance ages in fossil teeth (Lopes et al 2010(Lopes et al , 2014. Then, according to these authors, System II was deposited around 200 ka, and Barrier I is likely to be correlated to stage 9 (Fig.…”

“…GPR and seismic profiles (Fig. 13) show Geomorphology, remote sensing, outcrops, drilling, dating, GPR Barrier-lagoon Systems I or II through IV (part of high frequency sequences, each sequence cyclicity is 100 ka) Villwock, (1984), Villwock and Tomazelli (1995), Tomazelli and Villwock (2000), Lopes et al (2010Lopes et al ( , 2013Lopes et al ( , 2014, Rosa (2012) High II 20 ka Geomorphology, remote sensing, outcrops, drilling, dating, seismic, GPR System IV evolution (part of the younger high frequency sequence) Tomazelli & Villwock (1989), Dillenburg et al (2000Dillenburg et al ( , 2009, Tomazelli et al (2008), Barboza et al (2009, 2011), Rosa (2012, Dillenburg and Barboza (2014) High III 500, 300, 60 and 22 yr Geomorphology, remote sensing, including historical data, outcrops, drills, dating, beach profiles, monitoring of shoreline (DGPS), tide gauge, climatic, and meteorological data Phases of dunes (~500 yr), Lagoon level rise (Lagoa dos Patos -300 yr), increased vegetation in dune fields (60 yr), shoreline erosion (22 yr) Toldo Jr. et al (1999, 2004, Barboza et al (2006), Martinho et al (2008Martinho et al ( , 2009Martinho et al ( , 2010, Rosa (2012), Dillenburg et al 2017 (in press) the contact between the valley bottom and System III. 14 C age dating of shells obtained in SPT cores on the barrier indicates a Holocene age above this contact.…”