Lithologic and structural controls on fluvial knickzones in basalts of the Paraná Basin, Brazil

Lima, Arinilson Moreira Chaves; Binda, Andrey Luís

doi:10.1016/j.jsames.2013.10.004

Cited by 25 publications

(24 citation statements)

References 36 publications

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“…Despite the fact that knickzones are worldwide distributed and geologically well studied (Crosby and Whipple, 2006;Hayakawa and Oguchi, 2009;Dibiase et al, 2014;Lima and Binda, 2013), they are practically unknown environments in terms of ecological structure and limnological functioning. This lack of knowledge can be explained by the inherent difficulties to access this kind of environment, including total impossibility of safe navigation.…”

Section: Introductionmentioning

confidence: 99%

A contribution for the limnological knowledge of basaltic knickzones

2017

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The knickzones are defined as locally steep riverbed segments, such as a convex reach in a concave-up longitudinal profile. They are worldwide distributed and geologically well studied, but despite their distinctiveness as a particular kind of macrohabitat there is a notorious lack of ecological knowledge. In this context, this research proposal aims to provide a physical description, in terms of kind of habitats, and a limnological characterization of a basaltic knickzone. Information is based on a case study carried out in the Sapucaí-Mirim River, Southeast Brazil. Samplings were performed in three different habitats well represented in the knickzone (runs, riffles and pools) during rainy and dry conditions. A clear discrimination in terms of habitat type and seasonality was demonstrated through a principal component analysis. Pools exhibited higher amplitude of variation for most limnological parameters when compared to runs and riffles, probably due to a great influence of the internal metabolism (photosynthetic production and community respiration). Despite of their geological ancient formation and the little understanding of their ecological role, the knickzones are in imminent threat in several regions of the world by hydropower dams implementation. The lack of ecological information on knickzones is probably due to inherent access difficulties and how to compare the distinct kinds of habitats. Thereby, further studies should be encouraged.Keywords: run, riffle, pool, river longitudinal profile, limnological variables. Uma contribuição para o conhecimento limnológico dos pedrais basálticos ResumoOs pedrais são definidos como segmentos de rio com leito localmente íngreme, tais como um alcance convexo em um perfil longitudinal côncavo. Eles são mundialmente distribuídos e geologicamente bem estudados, mas apesar de sua distinção como um tipo particular de macrohabitat há uma notória falta de conhecimento ecológico. Neste contexto, a proposta desta pesquisa é fornecer uma descrição física, em termos de tipo de habitats, e uma caracterização limnológica de um pedral basáltico. A informação é baseada em um estudo de caso realizado no rio Sapucaí-Mirim, no Sudeste do Brasil. As amostragens foram realizadas em três diferentes habitats bem representados na zona de pedral (rápidos, corredeiras e poças) durante as condições chuvosa e seca. Uma clara discriminação em termos de tipo de habitat e sazonalidade foi demonstrada através de uma análise de componentes principais. As poças apresentaram maior amplitude de variação para a maioria dos parâmetros limnológicos quando comparadas aos rápidos e corredeiras, provavelmente devido a grande influência do metabolismo interno (produção fotossintética e respiração das comunidades). Apesar de sua formação geológica antiga e da pouca compreensão de seu papel ecológico, os pedrais estão em ameaça iminente em várias regiões do mundo pela implementação de barragens hidrelétricas. A falta de informações ecológicas sobre os pedrais é provavelmente devido às dificuldades i...

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Section: Introductionmentioning

confidence: 99%

A contribution for the limnological knowledge of basaltic knickzones

2017

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“…3). This detailed survey, which served to develop another study (Lima and Binda, 2013), also allowed us to identify several bedrock reaches with and without abrasion features. Aiming to expand the number of observations of bedrock reaches, especially under higher discharge, three reaches were subsequently analyzed ( Fig.…”

Section: Methodsmentioning

confidence: 99%

“…The flow of these rivers is in the back region of the sandstoneebasalt escarpment (Serra Geral), which marks the eastern boundary of the occurrence of volcanic rocks in the Paran a Basin in the Paran a state. The channel of the rivers on the plateau can be characterized as a mixed bedrock-alluvial, having sections with little alluvial cover (thickness <1 m), consisting of coarse sand to boulders, and sections of exposed bedrock (Lima and Binda, 2013).…”

Section: Study Areamentioning

confidence: 99%

“…In the PVP, fracturing in both types of basaltic zones was evaluated by Lima and Binda (2013) and showed no significant difference in their means (4.26 m/m 2 for vesicular units and 4.42 m/ m 2 massive units). Although the means are equal, the range of values varies from 1 to 10 m/m 2 in both units (unpublished data surveyed by Lima and Binda, 2013). Thus, an open question remains about what joint density value is favorable for potholes formation.…”

Section: Introductionmentioning

confidence: 99%

“…Based on the theoretical assumption and empirical findings, several authors point out the reduction of abrasive processes in highly jointed rocks (e.g., Hancock et al, 1998;Whipple et al, 2000a;Dubinski and Wohl, 2013). In the PVP, fracturing in both types of basaltic zones was evaluated by Lima and Binda (2013) and showed no significant difference in their means (4.26 m/m 2 for vesicular units and 4.42 m/ m 2 massive units). Although the means are equal, the range of values varies from 1 to 10 m/m 2 in both units (unpublished data surveyed by Lima and Binda, 2013).…”

Section: Introductionmentioning

confidence: 99%

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Differential control in the formation of river potholes on basalts of the Paraná Volcanic Province

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Bedrock fracture influences on geomorphic process and form across process domains and scales

Scott

Wohl

2018

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10Fractures are discontinuities in rock that can be exploited by erosion. Fractures 11 regulate cohesion, profoundly affecting the rate, style, and location of Earth surface 12 processes. By modulating the spatial distribution of erodibility, fractures can focus 13 erosion and set the shape of features from scales of fluvial bedforms to fjords. Although 14 early investigation focused on fractures as features that influence the orientation and 15 location of landforms, recent work has started to discern the mechanisms by which 16 fractures influence the erodibility of bedrock. As numerical modeling and field 17 measurement techniques improve, it is rapidly becoming feasible to determine how 18 fractures influence geomorphic processes, as opposed to when or where. However, 19 progress is hampered by a lack of coordination across scales and process domains. We 20 review studies from hillslope, glacial, fluvial, and coastal domains from the scale of 21 reaches and outcrops to entire landscapes. We then synthesize this work to highlight 22 similarities across domains and scales as well as suggest knowledge gaps, 23 opportunities, and methodological challenges that need to be solved. By integrating 24 knowledge across domains and scales, we present a more holistic conceptualization of 25 fracture influences on geomorphic processes. This conceptualization enables a more 26 unified framework for future investigation into fracture influences on Earth surface 27 dynamics. 28 29

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Lithologic and structural controls on fluvial knickzones in basalts of the Paraná Basin, Brazil

Cited by 25 publications

References 36 publications

A contribution for the limnological knowledge of basaltic knickzones

A contribution for the limnological knowledge of basaltic knickzones

Differential control in the formation of river potholes on basalts of the Paraná Volcanic Province

Bedrock fracture influences on geomorphic process and form across process domains and scales

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