OSL dating of sediments from a mountainous river in southeastern Brazil: Late Cenozoic tectonic and climatic implications

Magalhães, Antônio Pereira; Cherem, Luís Felipe Soares; Barros, Luiz Fernando de Paula; Santos, Gisele Barbosa dos

doi:10.1016/j.geomorph.2011.05.008

Cited by 17 publications

(5 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The QF reveals significant Cenozoic tectonic activity, with evidence of neotectonic activity persisting into the Quaternary period (Bacellar et al, 2005; Barros & Magalhães, 2020; Figueiredo et al, 2004; Lana & Castro, 2010; Magalhães et al, 2011; Magalhães & Saadi, 1994; Salgado et al, 2007; Sant’anna et al, 1997; Varajão et al, 2009). In addition, studies in the QF region have highlighted considerable bioclimatic fluctuations during the Late Pleistocene and Holocene (Araujo et al, 2005; Barros et al, 2016; Behling & Lichte, 1997; Gomes et al, 2009; Parizzi et al, 1998).…”

Section: Methodology and Methodsmentioning

confidence: 99%

“…The QF is located in the Atlantic Plateau, Southeast Brazil, and covers an area of nearly 7000 km 2 (Figure 2a Studies on the relief evolution of the QF have highlighted the role of tectonics, regional structures and differential denudation (Barbosa & Rodrigues, 1967;Dorr, 1969;King, 1956;Salgado et al, 2008;Varajão, 1991). The area has rich and complex geology, including (Alkmim & Marshak, 1998): Archean and Proterozoic crystalline complexes (gneisses, migmatites and granitoids), Archean greenstone belt sequence of 2.76 Ga (Hartmann et al, 2006) The QF reveals significant Cenozoic tectonic activity, with evidence of neotectonic activity persisting into the Quaternary period (Bacellar et al, 2005;Barros & Magalhães, 2020;Figueiredo et al, 2004;Lana & Castro, 2010;Magalhães et al, 2011;Magalhães & Saadi, 1994;Salgado et al, 2007;Sant'anna et al, 1997;Varajão et al, 2009). In addition, studies in the QF region have highlighted considerable bioclimatic fluctuations during the Late Pleistocene and Holocene (Araujo et al, 2005;Barros et al, 2016;Behling & Lichte, 1997;Gomes et al, 2009;Parizzi et al, 1998).…”

Section: Study Areamentioning

confidence: 99%

See 1 more Smart Citation

Ferricretes in fluvial archives of a tropical iron province: Records of the Late Quaternary landscape dynamics in the Brazilian Atlantic Plateau

de Paula Barros,

de Oliveira,

Magalhães

et al. 2024

Earth Surf Processes Landf

View full text Add to dashboard Cite

The occurrence of iron‐rich rocks in some areas makes possible the formation of duricrusts in positions from the relief tops to the slopes and valley bottoms, as is the case of the Quadrilátero Ferrífero (QF—‘Iron Quadrangle’) in the Brazilian Atlantic Plateau. This study aimed to analyse these materials in the Late Pleistocene fluvial archives of the QF to contribute to the understanding of the complex processes involved in the evolution of surface coverage in tropical regions. The results showed an essential external iron source for the Fe‐cemented alluvium, that is, they are ferricretes. Two ferricrete facies were identified: plate‐shaped and conglomeratic. They are characterised by the infilling of a primary porous system with crystalline and amorphous ferruginous phases or grain coatings by ferruginous materials. In plate‐shaped ferricretes, the size of the cemented grains differentiates the identified subtypes. Conglomeratic ferricretes can be subdivided into ferruginous and aluminous, and feature two types of cementing microstructures: septary and microlaminar. The results of the X‐ray diffraction analysis of the conglomeratic ferricretes highlight the strong presence of goethite (more common) and hematite. The chemical composition corroborated the mineralogical analysis, with the septa having an average iron‐rich composition. Aluminous conglomeratic ferricretes also occur and are the oldest in the area; their cement is composed mainly of gibbsite. Thus, it can be considered (i) a possible past source area of aluminous sediments or (ii) the in situ deferruginisation of a first level of ferricretes. A certain granulometric control in both ferricrete facies reinforces the importance of transport and deposition during ferricrete genesis. However, the cementing of sediments under supergene conditions and their microstructural variety suggest that their formation and evolution also occurred as a result of lateritic processes. Furthermore, the ferricretes revealed integration with the regional relief evolution, and the conglomeratic ones may be associated with lower rates of drainage incisions in some valleys.

show abstract

Section: Methodology and Methodsmentioning

confidence: 99%

Section: Study Areamentioning

confidence: 99%

Ferricretes in fluvial archives of a tropical iron province: Records of the Late Quaternary landscape dynamics in the Brazilian Atlantic Plateau

de Paula Barros,

de Oliveira,

Magalhães

et al. 2024

Earth Surf Processes Landf

View full text Add to dashboard Cite

show abstract

“…associated with climate changes and vegetation advance and retreat (Bacellar et al, 2005;Costa et al, 2014;Magalhães et al, 2011). Nowadays, deforestation can have the same effect, exposing these regions to debris flow risk.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Assessment of the debris-flow susceptibility in tropical mountains using clast distribution patterns

2016

View full text Add to dashboard Cite

“…The fill terrace and nested-fill terrace are depositional forms while the strath and fill-cut terraces are erosional forms. Modified from Hargitai and Larson, in press. surface is abandoned, but to a lower level than the initial fill terrace (Easterbrook, 1999;Junior et al, 2011;Waitt, 1979).…”

Section: The Terrace Form 1 Fluvial Terracesmentioning

confidence: 99%

“…Another form of a depositional terrace is a nested-fill terrace, where a river experiences an aggradational episode followed by incision. Another wave of aggradation ensues and that surface is abandoned, but to a lower level than the initial fill terrace (Easterbrook, 1999;Junior et al, 2011;Waitt, 1979).…”

Section: The Terrace Form 1 Fluvial Terracesmentioning

confidence: 99%

Toe-cut terraces

Larson

Dorn

Faulkner

et al. 2015

Progress in Physical Geography: Earth and Environment

View full text Add to dashboard Cite

Alluvial fans and fluvial terraces occur in nearly all climatic settings and often coexist within the same drainage basin. These landforms play an important role in understanding the geomorphic, hydrologic, sedimentologic and erosional histories of a basin. The juxtaposition of fans and fluvial terraces, in some instances, can lead to misinterpretation in distinguishing traditional fluvial terraces from the truncated toe of tributary alluvial fans. This becomes particularly troublesome for those attempting to interpret results from published field studies where fan-cut terrace, truncated alluvial fan, toe-cut alluvial fan, alluvial terrace, and incision of the lower end of a fan piedmont all refer to the same genetic landform. We call for use of the term ''toe-cut terrace'' to represent this landform. We also present criteria to aid in the identification of toe-cut terraces, defined as an abandoned alluvial surface, formed by the truncation of the distal portion of tributary alluvial fans by streams flowing obliquely or perpendicular to the fan surface. Truncation occurs through lateral erosion (''toe-cutting'') or through vertical incision by the trunk drainage lowering the base-level of the alluvial fan. This results in incision into the fan surface abandoning the fan's depositional surface at a higher level above the modern floodplain -a form that often resembles a fluvial terrace. A case study from the Sonoran Desert in central Arizona illustrates a sequence of abandoned alluvial surfaces that resemble fluvial terraces, but use of the proposed criteria reveal the presence of both toe-cut terraces and traditional fluvial terraces formed by the abandonment of the rivers former floodplain.

show abstract

OSL dating of sediments from a mountainous river in southeastern Brazil: Late Cenozoic tectonic and climatic implications

Cited by 17 publications

References 38 publications

Ferricretes in fluvial archives of a tropical iron province: Records of the Late Quaternary landscape dynamics in the Brazilian Atlantic Plateau

Ferricretes in fluvial archives of a tropical iron province: Records of the Late Quaternary landscape dynamics in the Brazilian Atlantic Plateau

Assessment of the debris-flow susceptibility in tropical mountains using clast distribution patterns

Toe-cut terraces

Contact Info

Product

Resources

About