Two million years of river and cave aggradation in NE Brazil: Implications for speleogenesis and landscape evolution

Laureano, Fernando Verassani; Karmann, Ivo; Granger, Darryl E.; Auler, Augusto S.; Almeida, Renato Paes de; Cruz, F. W.; Strícks, Nicolás M.; Novello, Valdir F.

doi:10.1016/j.geomorph.2016.08.009

Cited by 28 publications

(17 citation statements)

References 57 publications

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“…Quaternary climatic variations may increase or reduce discharge, affecting sediment flux in fluvial catchments, either due to periglacial/glacial processes in high latitudes or increased rainfall in tropical areas, along with vegetation cover evolution (bio‐rhexistasy). This may trigger episodic valley aggradation, causing hiatuses in base‐level lowering, or even base‐level rise (Laureano et al ., 2016). The latter is most likely in karst conduit systems developed at or close to the water table adjacent to major rivers (Constantin et al ., 2001; Granger et al ., 2001).…”

Section: Introductionmentioning

confidence: 99%

Reconstructing fluvial incision rates based on palaeo‐water tables in chalk karst networks along the Seine valley (Normandy, France)

Nehmé

Farrant

Ballesteros

et al. 2020

Earth Surf Processes Landf

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Quantifying rates of river incision and continental uplift over Quaternary timescales offer the potential for modelling landscape change due to tectonic and climatic forcing. In many areas, river terraces form datable archives that help constrain the timing and rate of valley incision. However, old river terraces, with high‐level deposits, are prone to weathering and often lack datable material. Where valleys are incised through karst areas, caves and sediments can be used to reconstruct the landscape evolution because they can record the elevation of palaeo‐water tables and contain preserved datable material. In Normandy (N. France), the Seine River is entrenched into an extensive karstic chalk plateau. Previous estimates of valley incision were hampered by the lack of preserved datable fluvial terraces. A stack of abandoned phreatic cave passages preserved in the sides of the Seine valley can be used to reconstruct the landscape evolution of the region. Combining geomorphological observations, palaeomagnetic and U/Th dating of speleothem and sediments in eight caves along the Lower Seine valley, we have constructed a new age model for cave development and valley incision. Six identified cave levels up to ∼100 m a.s.l. were formed during the last ~1 Ma, coeval with the incision of the Seine River. Passage morphologies indicate that the caves formed in a shallow phreatic/epiphreatic setting, modified by sediment influxes. The valley's maximum age is constrained by the occurrence of late Pliocene marine sand. Palaeomagnetic dating of cave infills indicates that the highest‐level caves were being infilled prior to 1.1 Ma. The evidence from the studied caves, complemented by fluvial terrace sequences, indicates that rapid river incision occurred during marine isotope stage (MIS) 28 to 20 (0.8–1 Ma), with maximal rates of ~0.30 m ka−1, dropping to ~0.08 m ka−1 between MIS 20–11 (0.8–0.4 Ma) and 0.05 m ka−1 from MIS 5 to the present time. © 2020 John Wiley & Sons, Ltd.

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Section: Introductionmentioning

confidence: 99%

Reconstructing fluvial incision rates based on palaeo‐water tables in chalk karst networks along the Seine valley (Normandy, France)

Nehmé

Farrant

Ballesteros

et al. 2020

Earth Surf Processes Landf

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“…The LORM‐like (i.e. slackwater facies) deposits are commonly observed in (fossiliferous) caves around the world – for example, Selminum Tem Cave in Papua New Guinea (Gillieson, ), Agen Allwedd cave in South Wales, England (Bull, ), Bather's Cave, Virginia, USA (Knapp et al ., ) and Liang Bua, Indonesia (Sutikna et al ., ; Morley et al ., ), but UMCB‐like facies appear to have been reported only from non‐fossiliferous caves – for example, Botovskaya Cave in Siberia (Filippov, ; Kadlec et al ., ) and Lapa Doce cave in north‐east Brazil (Laureano et al ., ). Archaeologically and palaeoanthropologically important cave systems, primarily from Africa, Europe and south‐east Asia, host thick successions of LORM facies‐type deposits.…”

Section: Discussionmentioning

confidence: 97%

Formation of mud clast breccias and the process of sedimentary autobrecciation in the hominin‐bearing (Homo naledi) Rising Star Cave system, South Africa

2019

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Unconsolidated mud clast breccia facies in the hominin-bearing (Homo naledi) Rising Star Cave, Cradle of Humankind, South Africa, are interpreted to have formed through a process termed sedimentary autobrecciation in this study. This process, by which most of the angular mud clast breccia deposits are thought to have formed autochthonously to para-autochthonously via a combination of erosion, desiccation, diagenesis and microbial alteration of laminated mud deposits, is thought to have taken place under relatively dry (i.e. non-flooded) conditions inside the cave. Subsequently, gravitational slumping and collapse was the dominant mechanism that produced the mud clast breccia deposits, which commonly accumulate into debris aprons. The mud clast breccia is typically associated with (micro) mammal fossils and is a common facies throughout the cave system, occurring in lithified and unlithified form. This facies has not been described from other cave localities in the Cradle of Humankind. Additionally, sedimentary autobrecciation took place during the deposition of some of the fossils within the Rising Star Cave, including the abundant Homo naledi skeletal remains found in the Dinaledi Subsystem. Reworking of the mud clast breccia deposits occurs in some chambers as they slump towards floor drains, resulting in the repositioning of fossils embedded in the breccias as evidenced by cross-cutting manganese staining lines on some Homo naledi fossil remains. The formation of the unlithified mud clast breccia deposits is a slow process, with first order formation rates estimated to be ca 8 9 10 À4 mm year À1 . The slow formation of the unlithified mud clast breccia facies sediments and lack of laminated mud facies within these deposits, indicates that conditions in the Dinaledi Chamber were probably stable and dry for at least the last ca 300 ka, meaning that this study excludes Homo naledi being actively transported by fluvial mechanisms during the time their remains entered the cave.

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“…Entretanto o processo de dissolução epigênica também exerce importante papel na carstifi cação e formação do modelado, sendo, o responsável pela elevada conectividade na zona mais rasa do aquífero. Segundo Laureano et al (2016) os sistemas de cavernas foram palco de pelo menos dois milhões de anos de injeção de sedimentos detríticos, característicos de uma evolução epigênica, que podem ter mascarado possíveis feições morfológicas hipogênicas pré-existentes. A permeabilidade terciária (WHITE, 1999;WHITE, 2002) De maneira geral, a superfície piezométrica acompanha a topografi a do terreno, no sentido do rio Santo Antônio -principal sistema exutório subterrâneo.…”

Section: Matriz De Corelaçãounclassified

“…Estudos realizados nos carbonatos na região culminaram com o cadastramento de mais de uma centena de cavidades, de modo que a área representa o local de maior densidade de condutos subterrâneas por unidade de área do país (AULER e FERRANT,1996). Para além destes fatos, a região estudada é também alvo de importantes investigações cientifi cas, principalmente aquelas relacionadas a mudanças paleoambientais (BARRETO, 2010;BICHUETTE et al, 2015;LAUREANO et al, 2016), e a participação de ácido sulfúrico na evolução dos condutos cársticos (VALLE, 2004). Entretanto, o estudo da relação do relevo com os aspectos hidrogeológicos ainda não foram explorados.…”

Section: Introductionunclassified

Influência Dos Aspectos Hidrogeológicos De Aquíferos Cársticos Na Evolução Do Relevo: Porção Central Da Chapada Diamantina, Bahia, Brasil

Salles

Leal

Pereira

et al. 2018

Rev. Bras. Geomorfol.

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Resumo:O presente trabalho discute como o funcionamento hidrogeológico do aquífero cárstico condiciona e interage com a evolução morfológica do relevo. O sistema cárstico situado na porção central da Chapada Diamantina, Bahia, Brasil abriga um conjunto de sítios espeleológicos de relevância no país. A região é palco de importantes descobertas científi cas, particularmente relacionados à espeleologia e evolução dos terrenos cársticos. Entretanto, a compreensão das relações existentes entre a morfologia e a hidráulica subterrânea ainda estão pouco exploradas. Com esse intuito, foram realizados estudos comparativos entre as feições morfológicas

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Two million years of river and cave aggradation in NE Brazil: Implications for speleogenesis and landscape evolution

Cited by 28 publications

References 57 publications

Reconstructing fluvial incision rates based on palaeo‐water tables in chalk karst networks along the Seine valley (Normandy, France)

Reconstructing fluvial incision rates based on palaeo‐water tables in chalk karst networks along the Seine valley (Normandy, France)

Formation of mud clast breccias and the process of sedimentary autobrecciation in the hominin‐bearing (Homo naledi) Rising Star Cave system, South Africa

Influência Dos Aspectos Hidrogeológicos De Aquíferos Cársticos Na Evolução Do Relevo: Porção Central Da Chapada Diamantina, Bahia, Brasil

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