Source and Sediment

Ibbeken, Hillert; Schleyer, Ruprecht

doi:10.1007/978-3-642-76165-2

Cited by 35 publications

(18 citation statements)

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“…, and show that feldspar depletion becomes progressively more pronounced as chemical weathering proceeds, and the resulting sands become progressively less representative of the source rock mineralogy, and shifted towards a quartzose composition. Ibbeken and Schleyer (1991) found that, in southern Calabria where climate is invariant with respect to the Sila Massif, the effects of chemical weathering are diluted by overwhelming consequences of slope instability, with huge landslides that constitute the most important sources of immature debris for fluvial transport and deposition.…”

Section: Discussionmentioning

confidence: 98%

Weathering, erosion and sediment composition in a high-gradient river, Calabria, Italy

Pera

Sorriso‐Valvo

2000

Earth Surf. Process. Landforms

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Source rock lithology and immediate modifying processes, such as chemical weathering and mechanical erosion, are primary controls on fluvial sediment supply. Sand composition and Chemical Index of Alteration (CIA) of parent rocks, soil and fluvial sand of the Savuto River watershed, Calabria (Italy), were used to evaluate the modifications of source rocks through different sections of the basin, characterized by different geomorphic processes, in a sub-humid Mediterranean climate. The headwaters, with gentle topography, produce a coarse-grained sediment load derived from deeply weathered gneiss, having sand of quartzofeldspathic composition, compositionally very different from in situ degraded bedrock. Maximum estimated CIA values suggest that source rock has been affected significantly by weathering, and it testifies to a climatic threshold on the destruction of the bedrock.The mid-course has steeper slopes and a deeply incised valley; bedrock consists of mica-schist and phyllite with a very thin regolith, which provides large cobble to very coarse sand sediments to the main channel. Slope instability, with an areal incidence of over 40 per cent, largely supplies detritus to the main channel. Sand-sized detritus of soil and fluvial sand is lithic. Estimated CIA value testifies to a significant weathering of the bedrock too, even if in this part of the drainage basin steeper slopes allow erosion to exceed chemical weathering.The lower course has a braided pattern and sediment load is coarse to medium±fine grained. The river cuts across Palaeozoic crystalline rocks and Miocene siliciclastic deposits. Sand-sized detritus, contributed from these rocks and homogenized by transport processes, has been found in the quartzolithic distal samples.Field and laboratory evidence indicates that landscape development was the result of extensive weathering during the last postglacial temperature maximum in the headwaters, and of mass-failure and fluvial erosional processes in the midand low course.

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Section: Discussionmentioning

confidence: 98%

Weathering, erosion and sediment composition in a high-gradient river, Calabria, Italy

Pera

Sorriso‐Valvo

2000

Earth Surf. Process. Landforms

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“…Weathering is greatly affected by climate and relief (Krynine, 1950;Folk, 1968;Basu, 1976Basu, ,1985Grantham, 1986;Grantham and Velbel, 1988;Ibbeken and Schleyer, 1991). In this work we compare the outcrop areas of different bedrock types with the modal composition of beach sands.…”

Section: Introductionmentioning

confidence: 98%

“…We neither corrected map areas for the slope of the terrain nor compensated for differential erosion of bedrock (cf. Grantham and Velbel, 1988;Ibbeken and Schleyer, 1991).…”

Section: Introductionmentioning

confidence: 98%

Beach sands of Elba Island, Tuscany, Italy: Roundness study and evidence of provenance

Picard

McBride²

1993

Processes Controlling the Composition of Clastic Sediments

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We studied the composition and roundness of medium sand from 18 small beaches of Elba Island. Six are pocket beaches less than 100 m long; the longest is 1.3 km long. The drainage basins of streams that supply the beaches are all less than 25 km 2 ; most are less than 5 km 2 . Beach sands range widely in composition owing to diverse source terrane.For the various drainage basins, comparison of the outcrop areas of the different types of bedrock with the compositions of beach sand grains yields the following conclusions: (1) the relative area of granodiorite outcrop is accurately represented by the amount of quartz + feldspar + quartzofeldspathic rock fragments in all beaches, although plagioclase in beach sand is significantly reduced relative to K-feldspar; (2) the relative areas of outcrop of ophiolitic and limestone bedrock are accurately represented by beach sand in pocket beaches, but are only moderately represented (ophiolitic rocks) or poorly represented (limestone) in other beaches; (3) the relative area of outcrop of metamorphic rocks is poorly represented in beach sand (metamorphic rock fragments + polycrystalline quartz) except in one anomalous beach supplied in part by mine tailings; (4) the relative area of bedded chert outcrop is poorly represented in beach sand because bedded chert does not break down into sand-size grains; and (5) shale bedrock is not represented or is only marginally represented in beach sand.For Elba beaches in general, the order of increasing roundness of grains, and thus increasing rate of abrasion, is: quartz < plagioclase < K-feldspar and igneous rock fragments (quartzo-feldspathic) < serpentine < metamorphic rock fragments < carbonate rock fragments (CRFs). There are no significant differences in roundness with beach length for quartz, K-feldspar, or CRFs. There are also no significant differences in roundness for the same three grain types from beaches of different size drainage basins, which indicates there is no perceptible rounding of grains by streams.First-cycle monocrystalline quartz grains of medium sand are unrounded, although coarser grains show minor blunting of edges. The roundness of quartz, K-feldspar, and CRFs are all greater on the eastern, more protected part of the island. This reflects a significant proportion of recycled quartz and K-feldspar in the eastern beaches, but CRFs may undergo more rounding in beaches of low to moderate wave activity than in high-energy beaches. Figure 1. Generalized geologic map of Elba showing numbered sample localities. Complex I = Carboniferous and Triassic marble, dolomite, and quartzite; Complex II = Carboniferous to Jurassic metasedimentary rocks; Complex III = Carboniferous to Jurassic limestone, argillite, and sandstone; Complex IV = Jurassic and Cretaceous ophiolitic rocks, bedded chert, limestone, and argillite; Complex V = Cretaceous and Paleogene limestone, sandstone, and shale. Modified from Trevisan and Marinelli (1967). Numbers 1 through 18 indicate beach sites.

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“…Ibbeken and Schleyer, 1991) making the correct interpretation difficult. Therefore the benefit and the plausibility of every method has to be evaluated carefully.…”

Section: Combined Methods: Blessing or Curse?mentioning

confidence: 97%

“…Therefore, mixed sediment sources require additional analytical discrimination methods such as mineral chemistry, bulk-rock chemistry, and thermochronology on detrital minerals to complement traditional point-counting analysis on sandstone framework grain composition and heavy mineral associations (e.g. Heller and Frost, 1988;Dallmeyer and Neubauer, 1991;Ibbeken and Schleyer, 1991;Morton, 1991;Handler et al, 1997;Dunkle et al, 1998;Morton and Hallsworth, 1999;Von Eynatten, 2003).…”

Section: Provenance Analysis Of Sandstonesmentioning

confidence: 98%

Provenance of the Carboniferous Hochwipfel Formation (Karawanken Mountains, Austria/Slovenia) — Geochemistry versus petrography

Kutterolf¹,

Diener²,

Schacht³

et al. 2008

Sedimentary Geology

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Source and Sediment

Abstract: Cover picture: Calabrian Massif and Ionian Shelf. The scenery is topped by Mt. Scorda, 1572 m, 17 km from the coast. The Buonamico and Careri river basins feed the submarine canyon which reaches a depth of 750 m in the foreground, 8.5 km off the coast.

Cited by 35 publications

References 0 publications

Weathering, erosion and sediment composition in a high-gradient river, Calabria, Italy

Weathering, erosion and sediment composition in a high-gradient river, Calabria, Italy

Beach sands of Elba Island, Tuscany, Italy: Roundness study and evidence of provenance

Provenance of the Carboniferous Hochwipfel Formation (Karawanken Mountains, Austria/Slovenia) — Geochemistry versus petrography

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