Paleoenvironmental reconstruction of the Lower Mogi Guaçu River Basin (São Paulo State — Brazil), morphopedosedimentary records and fluvial processes André Luiz de Souza Celarino a, ⁎, Melina Mara de Souza b , Francisco Sergio Bernardes Ladeira a , Fresia Soledad Ricardi Torres Branco b a Department of Geography, State University of Campinas, R. João Pandiá Calógeras, 51, 13083 870 Campinas, Brazil b Department of Geology and Natural Resources, State University of Campinas, R. João Pandiá Calógeras, 51, 13083 870 Campinas, Brazil abstract article info Article history: Received 22 May 2012 Received in revised form 17 May 2013 Accepted 3 July 2013 Keywords: Alluvial soils Paleopalynology Environmental changes Fluvial geomorphology processes Floodplains The Mogi Guaçu River rises in Bom Repouso (Minas Gerais State — Brazil) in the Mantiqueira Ridge, and flows into the Rio Pardo river at an elevation of 483 m in Pontal (São Paulo State — Brazil), after running a 530 km long course. Especially along the Lower Mogi Guaçu Basin, the river morphology is extremely sinuous, character- ized by intense processes of channel migration, avulsion, abandonment and reactivation of the channel, produc- ing an extensive alluvial plain composed of a series of associated relief forms and sedimentary facies. Among these forms, point bar deposits by lateral accretion, abandoned meanders, paleo-channels and fluvial terraces are notable features. In this sense, the objective of this work was to investigate whether these features could be linked to environmental changes. To reach this goal, soil properties of a catena of the Jataí Ecological Station (Luiz Antonio — São Paulo State) were analyzed in four sectors: Slope, Terrace I, Terrace II and Alluvial Plain. The results from grain-size determination, geochemical and isotopic studies, dating, paleopalynology, coal frag- ments and micromorphology are presented in this paper. From these analyses, a paleo-environmental evolution divided in three stages is proposed for the area: 130,000 YBP (Upper Pleistocene), when the Mogi Guaçu River base level was approximately 6 m above the present one; a drier second phase 10,250 years BP (Lower Holocene), when an organic horizon was formed inside of an abandoned meander (oxbow lake), and a third phase, 2096 YBP (Upper Holocene), of reactivation of a warm and humid climate that promoted the development of a two meters thick Typic Udifluvent in a sector where the Mogi Guaçu River no more floods due to the incision of its thalweg, reaching more than six-meters depth in the last 130,000 years BP. Thus, this paper used a fluvial geomorphologic approach and its interplay with climate to understand how the landscape was shaped from Upper Pleistocene to Holocene, however, Neotectonics might have played a relevant role as well, not only in the Mogi Guaçu River Basin, but also in the Paraná Sedimentary Basin. © 2013 Elsevier B.V. All rights reserved. 1. Introduction During the Quaternary the Earth was affected by glacial and intergla- cial stages. It is estimated that during the last interglacial stage (130,000– 120,000 BP) known as Sangamon in North America and Eemian in Europe, the temperatures were higher and the relative sea level was between 4 and 6 m above the present one (Beets et al., 2006; Eynaud et al., 2004; Mercer, 1968; Shackleton, 1988; Shackleton et al., 2003). According to Dahl-Jensen et al. (2013), on the basis of water stable iso- topes, surface temperatures of the Eemian (126,000 years ago) peaked at 8 ± 4°C above the mean of the past millennium. The soil profiles of this period, in North America, are known as Sangamon Geosol (MIS-5) (Illinois-USA), which are well developed and relatively well preserved, evolved under hot climatic conditions and variable humidity (Curry and Backer, 2000; Grimley et al., 2003; Jacobs, 1998; Jacobs et al., 2009; McKay, 2007). In South America, Van der Hammen and Hooghiemstra (2003) pointed out that the temperatures in the Eastern Cordillera of Colombia were estimated maximally in 1 °C above the Holocene, under a dry condition. In the Uruguay River, fluvial deposits were attributed to the MIS-5 stage under a warm and humid climate (Krohling, 2009). In Brazil, Suguio and Martin (1978) showed that during the Cananeia transgression (120,000 BP), the relative sea level was 8 m above the present. Horn Filho and Simo (2008) studied marine deposits from 10 to 17 m above present mean sea level in an island in south Brazil, these deposits would represent the Cananeia transgression as well. However, the most widely studied period in Brazil corresponds to the last 30,000 years, from Late Pleistocene to Holocene (De Freitas et al., 2001; Ferraz-Vicentini and Salgado-Labouriau, 1999; Ledru et al., 1998; Pessenda et al., 2004; Turcq et al., 1997 and others). In this work proposed a 130 ka paleoenvironmental reconstruction using detailed analysis of an upland-to-lowland soil sequence is presented. In order to do this, our work was guided by the understand- ing how the river meandering processes, such as cut bank erosion and Catena 111 (2013) 80–97 ⁎ Corresponding author. Tel.: +55 19 9823 6099. E-mail address: andre.celarino@ige.unicamp.br (A.L.S. Celarino). 0341-8162/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.catena.2013.07.002 Contents lists available at ScienceDirect Catena journal homepage: www.elsevier.com/locate/catena