Clay minerals from the sedimentary cover from the Northwest Iberian shelf
TL;DR: In this article, the distributions of clay mineral in the top layer of the sedimentary cover are shown to be related to their continental sources, but also reflect the influences of winter storms and longshore currents in determining the pathways of sediment transport.
About: This article is published in Progress in Oceanography.The article was published on 2002-01-01. It has received 138 citations till now. The article focuses on the topics: Terrigenous sediment & Continental margin.
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TL;DR: In this article, a comparison between modern terrestrial and marine pollen signals in and off western Iberia shows that marine pollen assemblages give an integrated image of the regional vegetation colonising the adjacent continent.
241 citations
01 Mar 2015
TL;DR: In this article, the provenance and depositional history of continental slope sediments in the Southwestern Gulf of Mexico (~1089-1785m water depth) were studied for mineralogy, major, trace and rare earth element geochemistry.
Abstract: The aim of this work is to constrain the provenance and depositional history of continental slope sediments in the Southwestern Gulf of Mexico (~1089–1785 m water depth). To achieve this, 10 piston sediment cores (~5–5.5 m long) were studied for mineralogy, major, trace and rare earth element geochemistry. Samples were analyzed at three core sections, i.e. upper (0–1 cm), middle (30–31 cm) and lower (~300–391 cm). The textural study reveals that the core sediments are characterized by silt and clay fractions. Radiocarbon dating of sediments for the cores at different levels indicated a maximum of ~28,000 year BP. Sediments were classified as shale. The chemical index of alteration (CIA) values for the upper, middle, and lower sections revealed moderate weathering in the source region. The index of chemical maturity (ICV) and SiO 2 /Al 2 O 3 ratio indicated low compositional maturity for the core sediments. A statistically significant correlation observed between total rare earth elements (∑REE) versus Al 2 O 3 and Zr indicated that REE are mainly housed in detrital minerals. The North American Shale Composite (NASC) normalized REE patterns, trace element concentrations such as Cr, Ni and V, and the comparison of REE concentrations in sediments and source rocks indicated that the study area received sediments from rocks intermediate between felsic and mafic composition. The enrichment factor (EF) results indicated that the Cd and Zn contents of the upper section sediments were influenced by an anthropogenic source. The trace element ratios and authigenic U content of the core sediments indicated the existence of an oxic depositional environment.
198 citations
TL;DR: In this article, molecular variations of pore water DOM in surface sediments from the NW Iberian shelf were analyzed by ultra-high-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) and compared to river and marine water column DOM.
185 citations
Cites background from "Clay minerals from the sedimentary ..."
...Subsequent to the primary sedimentation close to the source, the terrestrial material is remobilized and transported northwards with the predominant currents (Oliveira et al., 2002; Vitorino et al., 2002b)....
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...The modern oceanography of Galicia was part of several studies (e.g., Coelho et al., 2002; Oliveira et al., 2002; Vitorino et al., 2002a,b; Alvarez-Salgado et al., 2003)....
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TL;DR: In this article, the OMEX core KSGX 40 of the Galicia Mud Deposit, of the NW Iberian outer continental shelf, off the Ria de Vigo (North of Spain) was used to study textural, mineralogical, geochemical, and microfaunal data (benthic foraminifera) along with the BFOI data.
117 citations
Cites methods from "Clay minerals from the sedimentary ..."
...For the semiquantification of the identified principal minerals, peak areas of the specific reflections were calculated and weighted by empirically estimated factors (Table 1), according to Galhano et al. (1999) and Oliveira et al. (2002)....
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TL;DR: In this article, the authors describe the mechanisms controlling the deposition of the fine-grained sediment depositions and the processes that result in resuspension processes on the Galicia-Minho Shelf.
103 citations
References
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TL;DR: In this article, the relative abundances of montmorillonite, illite, kaolinite, chlorite, gibbsite, pyrophyllite, mixed-layer clay minerals, feldspars, and dolomite were determined.
Abstract: Semiquantitative mineral analysis has been done by X-ray diffraction on the < 2 μ- and 2–20 μ-size fractions of approximately five hundred Recent deep-sea core samples from the Atlantic, Antarctic, western Indian Oceans, and adjacent seas. Relative abundances of montmorillonite, illite, kaolinite, chlorite, gibbsite, quartz, amphibole, clinoptilolite-heulandite(?), and pyrophyllite(?) were determined. Mixed-layer clay minerals, feldspars, and dolomite were also observed but not quantitatively evaluated. From the patterns of mineral distribution, the following conclusions appear warranted:
Most Recent Atlantic Ocean deep-sea clay is detritus from the continents. The formation of minerals in situ on the ocean bottom is relatively unimportant in the Atlantic but may be significant in parts of the southwestern Indian Ocean.
Mineralogical analysis of the fine fraction of Atlantic Ocean deep-sea sediments is a useful indicator of sediment provenance. Kaolinite, gibbsite, pyrophyllite, mixed-layer minerals, and chlorite contribute the most unequivocal provenance information because they have relatively restricted loci of continental origin.
Topographic control over mineral distribution by the Mid-Atlantic Ridge in the North Atlantic Ocean precludes significant eolian transport by the jet stream and emphasizes the importance of transport to and within that part of the deep-sea by processes operative at or near the sediment-water interface.
Transport of continent-derived sediment to the equatorial Atlantic is primarily by rivers draining from South America and by rivers and wind from Africa.
The higher proportion of kaolinite and gibbsite in deep-sea sediments adjacent to small tropical South American rivers reflects a greater intensity of lateritic weathering than is observed near the mouths of the larger rivers. This may be explained by a greater variety of pedogenic conditions in the larger drainage basins, resulting in an assemblage with proportionately less lateritic material in the detritus transported by the larger rivers despite their quantitatively greater influence on deep-sea sediment accumulation.
In the South Atlantic Ocean, the fine-fraction mineral assemblage of surface sediment in the Argentine Basin is sufficiently unlike that adjacent to the mouth of the Rio de la Plata to preclude it as a major Recent sediment source for that basin. The southern Argentine Continental Shelf, the Scotia Ridge, and the Weddell Sea arc mineralogically more likely immediate sources. Transport from the Weddell Sea by the Antarctic Bottom Water may be responsible for the northward transport of fine-fraction sediment along parts of the western South Atlantic as far north as the Equator.
2,001 citations
01 Jan 1964
TL;DR: In this article, the authors present an X-ray analysis of carbonate minerals, including sulfide, sulfate, and carbonate fraction data, and compare them with chemical analyses.
Abstract: -----------------------------------------Introduction.-------------------------------------X-ray analysis ________ --_--_--_----_________ ------Sample preparation and treatment _______________ _ Interpretation---------------------------------Whole rock data ___________________________ _ Carbonate minerals.--------_____ -----_ Disordered cristobalite _________________ _ Total clay minerals __ -------__________ _ Clay fraction data_------------__ ------__ _ Clay minerals present __ ----------------Comparison of X-ray peak sizes _________ _ Estimation of kaolinite and chlorite ______ _ Examples of interpretation __________________ _ ReproducibilitY------------------------------------Long-term reproducibility----__________________ _ Accuracy-comparison with chemical analyses _________ _ Sulfide, sulfate, and carbonate minerals ___________ _ Page
853 citations
Journal Article•
731 citations
Book•
01 Jan 1989
TL;DR: In this paper, the authorship of Physils in Sandstones is discussed. But they focus on Physils that grow in shallow marine, brackish, and evaporitic environments.
Abstract: I. Background. Nomenclature. II. Structure and Composition. Kaolin. Serpentine. Illite. Phengite. Smectite. Mixed-layer illite/smectite (I/S). Chlorite and chloritics. Vermiculite. Glauconite, celadonite. Talc, kerolite. Sepiolite, palygorskite. III. Soils and Weathering. Soil formation. Climate (and other factors). Chemical weathering processes. Pedogenic formation of physils. IV. Continental Transport and Deposition. Rivers. Estuaries. Marshes and tidal flats. Deltas. Lakes. V. Marine Transport and Deposition. Water transport. Atmospheric transport. Ice transport. Distribution of physils in the oceans. VI. "Authigenic Marine" Physils. Exchange reactions. Physil dissolution and precipitation. Formation of physils from marine volcanics. Physils that grow in shallow marine, brackish, and evaporitic environments. VII. Diagenesis Metamorphism. Diagenesis. Beyond diagenesis. Organic and physil paleothermometers. VIII. Physils in Sandstones. Introduction. Examples. IX. Evolution of Physils and Continents. Introduction. Precambrian. Early Paleozoic. Cambrian. Ordovician. Silurian. Devonian. Carboniferous. Permian. Triassic. Jurassic. Cretaceous. Cenozoic. Pleistocene. Paleoatlantic. X. Lithification and Petrology. Compaction. Sedimentary structures. Composition. Color. Thin sections. References. Author Index. Subject Index.
687 citations
TL;DR: In this article, the relative amounts of chlorite, montmorillonite, kaolinite and illite in the less than 2 micron size fraction of pelagic sediments are related to the sources and transport paths of solid phases from the continents to the oceans and to injections of volcanic materials to the marine environment.
555 citations