scholarly journals GEOQUÍMICA E PETROGRAFIA DE DEPÓSITOS QUATERNÁRIOS DA PORÇÃO SW DA PRAIA BRAVA, ARMAÇÃO DOS BÚZIOS, RJ, BRASIL: EDFRX E DIFRAÇÃO A LASER

GEOgraphia ◽  
2021 ◽  
Vol 23 (51) ◽  
Author(s):  
Diogo Gabriel Sperandio ◽  
Cristiane Heredia Gomes ◽  
Guilherme Pazinato Dias
Keyword(s):  
Chemical Weathering ◽  
Source Rocks ◽  
Unconsolidated Sediments ◽  
Moderate Degree ◽  
Quaternary Deposits ◽  
Geochemical Environment ◽  
Sedimentary Deposits ◽  
Palabras Clave ◽  
Beach Sediments ◽  
Textural Parameters

Resumo: Este artigo apresenta os dados geoquímicos e petrográficos de sedimentos praiais da região SW da Praia Brava (PB) em Armação dos Búzios-RJ. Buscamos discutir os processos de intemperismo químico e proveniência, bem como, analisar o ambiente geoquímico e a sua relação com as fontes autóctones. Neste estudo foram utilizadas análises petrográficas, parâmetros texturais na distribuição de partículas, geoquímica e estatística com auxílio de Laser Difraction e Fluorescência de Raios-X com Energia Dispersiva. Os sedimentos estudados são compostos essencialmente de granadas, biotita, piroxênio (diopsídio e augita?), epidoto, monazita, hornblenda, ilmenita, zircão, rutilo, titanita, silimanita, cianita, além de quartzo. Os sedimentos investigados são reflexo dos litotipos encontrados regionalmente, indicando possivelmente uma forte correlação entre as rochas-fonte e os depósitos sedimentares. O ambiente de oxirredução é demarcado pela presença de óxidos de Fe, provavelmente hematita. O índice de alteração calculado suporta um grau moderado, onde micas são preservadas, totalmente ou em partes. Palavras-Chave: Sedimentos Inconsolidados; Depósitos Praiais; Intemperismo Químico. GEOCHEMISTRY AND PETROGRAPHY OF QUATERNARY DEPOSITS FROM SW OF PRAIA BRAVA BEACH, ARMAÇÃO DOS BÚZIOS, RJ, BRAZIL:  EDFRX AND LASER DIFRACTION Abstract: This article presents the geochemical and petrographic data of beach sediments from the SW region of Praia Brava (PB) in Armação dos Búzios-RJ. We seek to discuss the processes of chemical weathering and provenance, as well as to analyze the geochemical environment and its relationship with autochthonous sources. In this study, petrographic analyzes, textural parameters in particle distribution (Laser Difraction), geochemistry (X-Ray Fluorescence with Dispersive Energy) and statistics were used. The studied sediments are essentially composed of garnets, biotite, pyroxene (diopside and augite?), epidote, monazite, hornblende, ilmenite, zircon, rutile, titanite, silimanite, kyanite, and quartz. The investigated sediments are similar to the lithotypes found regionally, thus possibly indicating a strong correlation between source rocks and sedimentary deposits. The redox environment is marked by the presence of Fe oxides, probably hematite. The alteration index supports a moderate degree, where micas are preserved, in whole or in part. Keywords: Unconsolidated Sediments, Beach Deposits; Chemical watering. GEOQUÍMICA Y PETROGRAFÍA DE DEPÓSITOS CUTERNARIOS DE LA PORCIÓN SW DE PRAIA BRAVA, ARMAÇÃO DOS BÚZIOS, RJ, BRASIL: EDFRX Y DIFFRACCIÓN LÁSER Resumen: Este artículo presenta los datos geoquímicos y petrográficos de sedimentos de playa de la región SO de Praia Brava (PB) en Armação dos Búzios-RJ. Buscamos discutir los procesos de meteorización química y procedencia, así como analizar el entorno geoquímico y su relación con fuentes autóctonas. En este estudio se utilizaron análisis petrográficos, parámetros texturales en distribución de partículas, geoquímica y estadística con la ayuda de Difracción Láser y Fluorescencia de Rayos X con Energía Dispersiva. Los sedimentos estudiados están compuestos fundamentalmente por granate, biotita, piroxeno (¿diópsido y augita?), Epidota, monacita, hornblenda, ilmenita, circón, rutilo, titanita, silimanita, cianita, además de cuarzo. Los sedimentos investigados son un reflejo de los litotipos encontrados regionalmente, lo que posiblemente indique una fuerte correlación entre las rocas generadoras y los depósitos sedimentarios. El entorno redox está delimitado por la presencia de óxidos de Fe, probablemente hematita. El índice de cambio calculado admite un grado moderado en el que se conservan las micas, ya sea total o parcialmente. Palabras clave: Sedimentos no consolidados; Depósitos en la playa; Meteorización química.

scholarly journals STUDY REGARDING THE CARBONATICAL SOILS FROM THE TRANSYLVANIAN DEPRESSION FORMED ON THE EOCINICAL DEPOSITS OF NUMULITS

1970 ◽  
Vol 63 ◽  
Author(s):  
I. Pacurar ◽  
V. Bunescu ◽  
M. Darja ◽  
Doina Clapa ◽  
L. Holonec ◽  
...  
Keyword(s):  
Surface Coating ◽  
Soil Cover ◽  
Quercus Petraea ◽  
Point Of View ◽  
Agricultural Crops ◽  
Quaternary Deposits ◽  
Climate Conditions ◽  
Sedimentary Deposits ◽  
A Value ◽  
Average Annual Temperature

The Căpuşului hills are in the Transilvanian depression a trully ”geologycal eocenic golf” with a rich fossilifeuros fauna (Gryphaea eszerházy, G. gigantica, Turrietella imbricataria, Corbula gallica, Cepatia cepacea, Rotularia spirulaea) and also nummulitus species. The pedogenetic cover is constituted by sedimental deposits (clays, marls, limestones, gritsones). Also the pedogentic cover is represented by preluvisoils, luvisoils, eutricambisoils, clay cernozems. The relief characteristics are the Nummulites perforatus, N. fabianii and N. striatus who are the basically substrates from the acrobatically soils. The Transylvanian Depression is considered to be a true "geological eocenical gulf", is remarked through the conservation of a highly rich fossil fauna. Under the geological aspect, on a crystalline base is revealed the whole series of eocenical formations (striped clays, clays and limestone with "numuliti"), oligocenical (carbonatical clays, sands, sand stones and quaternary deposits) (Posea, 1978; Pop, 2001). These sedimentary deposits lay down from the half of the inferior Miocen and finished during the Panonian's end have constituted the parenthal material for the actual pedogenetical cover. A special characteristic of the landscape (with heights of 600-800m), from the outskirts of the Depression (the Huedin Depression, the Paniceni High hills, the Capus and Savadisla Corridor) is the fact that at the surface coating begin to appear "numulits" (Nummulites perforatus, N. fabianii, N. striatus), close to the localities Capusul mic, Leghia, Savadisla, Aghires, Manastireni, Cluj-Calvaria, Vlaha), deposits on which carbonatical soils are formed. If we view this are from the climate's point of view this area belongs to the Dfbk (Koppen) climatical province. The climate is a temperate continental of high hills, with forest. At Cluj-Napoca the average annual precipitations reach 613mm, the average annual temperature has a value of 8.3 degrees C, and the aridity indicator "De Martonne" has the value of 33.7. According to the climate conditions the studied area belongs to the level of oak (Quercus petraea) and the area of mezofilical oaks. (Quercus robur) Generally the areas of forest are mixed with those of pasture or agricultural crops. Because of the diversity of the ecological conditions the soil cover is extremely different, being constitueted of preluvosoils, luvosoils, eutricambosoils, cernosioms, carbonatical soils. (Blaga 1981, Bunescu &co 2005).

scholarly journals Geochemical Classification and Determination of Maturity Source Weathering in Beach Sands of Eastern San’ in Coast, Tango Peninsula, and Wakasa Bay, Japan

2016 ◽  
Vol 5 (1) ◽  
pp. 44 ◽  
Author(s):  
Bah Mamadou Lamine Malick ◽  
Hiroaki Ishiga
Keyword(s):  
Chemical Weathering ◽  
Tectonic Setting ◽  
Passive Margin ◽  
Beach Sand ◽  
Moderate Degree ◽  
Font Size ◽  
Chemical Index ◽  
Wakasa Bay ◽  
Beach Sands ◽  
Sand Sediments

<span style="font-size: 10.5pt; font-family: 'Times New Roman','serif'; mso-bidi-font-size: 10.0pt; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;" lang="EN-US">Geochemistry of beach sand sediments collected from the Eastern San’in coast (n=17), Tango Peninsula (n=14) and Wakasa Bay (n=7) shorelines were investigated using XRF analyses for major and trace elements to characterize their composition, classification, maturity, provenance, tectonic setting and degree of weathering in source areas. Investigated sands from all sites were very similar showing depletion in all elements except SiO<sub>2</sub>, K<sub>2</sub>O and As relative to the UCCN and JUCN, suggesting a moderate geochemical maturation. Beach sand sediments from these locations can be classified as arkose, subarkose and litharenite that are chemically immature and formed under arid/semi-arid conditions with a tendency towards increasing chemical maturity suggesting that they are from multiple sources. The relatively low to moderate values of weathering indices of Chemical Index of Alteration (CIA), Plagioclase Index of Alteration (PIA) and Chemical Index of Weathering (CIW), the beach sands from all sites in the source area have undergone low to moderate degree of chemical weathering. A-CN-K and A-CNK-FM plots, which suggest a granitic source composition, also confirm that the sand samples from these sites have undergone low to moderate degree of chemical weathering in consistent with CIA, PIA and CIW values. A plot of the analyzed beach sands data on the provenance discriminating function F1/F2 showed that most of the investigated beach sand sediments in all locations fall within mafic to intermediate ocean island arc source; similar to the tectonic setting discrimination diagrams based on major elements suggesting a passive margin.</span>

scholarly journals Heavy-mineral analysis in Polish investigations of Quaternary deposits: a review

Geologos ◽  
2013 ◽  
Vol 19 (1-2) ◽  
pp. 5-23 ◽  
Author(s):  
Bogusław Marcinkowski ◽  
Elżbieta Mycielska-Dowgiałło
Keyword(s):  
Chemical Weathering ◽  
Heavy Mineral ◽  
Heavy Minerals ◽  
Mineral Analysis ◽  
Quaternary Deposits ◽  
Mineral Research ◽  
Distinctive Features ◽  
Depositional Processes ◽  
Stratigraphic Position ◽  
Heavy Mineral Analysis

Abstract The composition of heavy-mineral assemblages is one of the main textural features of sediments because they can have significant value for the interpretation of, among others, their depositional environment, their depositional processes, and their stratigraphic position. Distinctive features of heavy minerals include their resistance to chemical weathering and mechanical abrasion, their habit, and their density. These parameters are the most widely used in the heavy-mineral research of Quaternary deposits in Poland, as well as in such research in other countries conducted by Polish scientists. Several other heavy-mineral parameters can also be used in various types of interpretation. It is discussed whether heavy-mineral analysis is decisive in the evaluation of deposits or whether it plays mainly a role that may support evidence obtained by other types of analysis. The attention is mainly devoted to transparent heavy minerals; the significance of opaque heavy minerals for interpretational purposes is only mentioned.

scholarly journals Geochemistry of the mudrocks and sandstones from the Bredasdorp Basin, offshore South Africa: Implications for tectonic provenance and paleoweathering

2021 ◽  
Vol 13 (1) ◽  
pp. 1187-1225
Author(s):  
Temitope Love Baiyegunhi ◽  
Kuiwu Liu ◽  
Oswald Gwavava ◽  
Christopher Baiyegunhi ◽  
Maropene Rapholo
Keyword(s):  
South Africa ◽  
Chemical Weathering ◽  
Tectonic Setting ◽  
Active Continental Margin ◽  
Source Area ◽  
Major And Trace Elements ◽  
Rift System ◽  
Moderate Degree ◽  
East African Rift System ◽  
Major Oxide

Abstract An inorganic geochemical investigation of mudrocks and sandstone from the southern Bredasdorp Basin, off the south coast of South Africa was carried out to unravel the provenance, paleoweathering, and tectonic setting of the basin. Seventy-seven representative samples from exploration wells E-AH1, E-AJ1, E-BA1, E-BB1, and E-D3 underwent geochemical analysis involving major and trace elements. The major oxide compositions show that the sandstones could be classified as sub-arkose and sub-lithic arenite. The provenance discrimination diagrams based on major oxide geochemistry revealed that the sandstones are mainly of quartzose sedimentary provenance, while the mudrocks are of quartzose sedimentary and intermediate igneous provenances. The discrimination diagrams indicate that the Bredasdorp sediments were mostly derived from a cratonic interior or recycled orogen. The bivariate plots of TiO2 versus Ni, TiO2 against Zr, and La/Th versus Hf as well as the ternary diagrams of V–Ni–Th∗10 suggest that the mudrocks and sandstones were derived from felsic igneous rocks. The tectonic setting discrimination diagrams support passive-active continental margin setting of the provenance. Also, the closely similar compositions of the analysed samples and recent sedimentary rocks of the East African Rift System perhaps suggest a rifted basin tectonic setting for the Bredasdorp Basin. Chemical index of alteration (CIA) indices observed in the sandstones suggest that their source area underwent low to moderate degree of chemical weathering. However, the mudrocks have high CIA indices suggesting that the source area underwent more intense chemical weathering, possibly due to climatic and/or tectonic variations.

scholarly journals Proposal for geological classification and nomenclature of soils: both genetic-descriptive and compositional-mineralogical

2020 ◽  
Vol 42 (1) ◽  
pp. 81-97
Author(s):  
Luis Enrique Cruz-Guevara ◽  
Luis Felipe Cruz-Ceballos ◽  
Gladys Marcela Avendaño-Sánchez ◽  
Mario García-González
Keyword(s):  
Chemical Weathering ◽  
Soil Classification ◽  
Original Structure ◽  
Rock Fragments ◽  
Sedimentary Deposits ◽  
Geological Processes ◽  
Detailed Classification ◽  
Clay Layers ◽  
Physical And Chemical

Numerous systems with detailed classification of soil are in existence. Most of them are based on a variety of complex criteria, such as material type and properties like the amount of organic material, presence of clay layers, and the presence of oxidation or reduction iron-rich horizons, as well as depositional characteristics, its landform morphology and depositional formation processes. Many of these have been developed for use in fields such as agronomy and geotechnics. This paper focuses on the classification of the soil by determining its materials, their origin and the geological processes that shape them, following these basic assumptions: (1) The soil initially comes from the weathering of a parent substrate that can be either sedimentary deposits (for example, alluvial or fluvial) or of any type of rock (igneous, metamorphic or sedimentary), (2) the parent substrate structure is composed by original sequential facies (e.g. foliation, igneous cumulates or stratigraphic intercalation of sedimentary layers), (3) the physical and chemical weathering and the biogenic activity and productivity processes that occur in the soil modify both the original structure and the constituents of the parental substrate, resulting in the formation of new materials, the conservation of others, and the overprint of the sequential facies of the soil (horizons A, B and C) developed on the original parental sequential facies, additionally (4) some materials will be lost from the system and others will be incorporated into it. Finally, a strictly compositional-mineralogical classification of soil is also proposed, which corresponds essentially to the main groups of minerals: silicates, carbonates, phosphates, oxides and hydroxides, sulfates, organic rich matter, nitrates, sulphides, borates, native elements and halides, named in sedimentology as monomaterials, plus the polymaterials or rock fragments (RF). This classification offers an advantage when examining materials that are not genetically linked to the parent substrates, making each soil profile unique, by highlighting the role played by the parental materials in this process. This classification is intended to complement, but not replace any existing soil classification

scholarly journals Geochemistry of Recent Brahmaputra River Sediments: Provenance, Tectonics, Source Area Weathering and Depositional Environment

Minerals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 813
Author(s):  
Md Aminur Rahman ◽  
Sudeb Chandra Das ◽  
Mark I. Pownceby ◽  
James Tardio ◽  
Md Sha Alam ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Element ◽  
Chemical Weathering ◽  
Earth Element ◽  
Tectonic Setting ◽  
River Sediments ◽  
Source Area ◽  
Source Rocks ◽  
Heavy Minerals ◽  
Brahmaputra River

Sediments from stable sand bars along a 40 km section of the Brahmaputra River in northern Bangladesh were analyzed for their major, trace and rare earth element contents to determine their provenance, compositional maturity, source area weathering and tectonic setting. Geochemically, the sediments were classified as litharenites and the Index of Compositional Variability (ICV) varied between 1.4 and 2.0, indicating low compositional and mineralogical maturity. A high mean SiO2 concentration (72.9 wt.%) and low Al2O3 (11.1 wt.%) were consistent with a low abundance of shale and clay components. The depletion of the oxide components Na2O, CaO and K2O relative to average upper crustal compositions (UCC) reflected loss of feldspar during chemical weathering in the source region. Average TiO2 values for most samples were higher than average crustal levels, consistent with the northern section of the Brahmaputra River being a potential resource for valuable Fe-Ti oxide heavy minerals. Major and trace element ratios indicated the sediments represented erosional products from typical felsic upper continental crustal materials with contamination (30%–40%) from more intermediate/mafic compositions. The rare earth element patterns showed negative Eu anomalies (0.57–0.71), indicating they were derived mainly from fractionated felsic rocks. Resemblance of the sediment compositions to mean compositions from Higher Himalaya crystalline rocks pointed to these being potential source rocks but with components from a mafic source also present. Major element chemistries and low to intermediate weathering indices for all sediments indicated a lack of substantial chemical weathering. Evidence from tectonic discrimination diagrams suggested the Brahmaputra River sediments were derived from rock types that formed in a transitional tectonic setting ranging from an ancient passive margin to an active continental margin. Deposition occurred under cool to semi-arid climatic conditions in an oxic environment.

Geochemistry and provenance of metasedimentary rocks from the Archean Golden Pond sequence (Casa Berardi mining district, Abitibi subprovince)

1996 ◽  
Vol 33 (5) ◽  
pp. 676-690 ◽  
Author(s):  
M. R. Flèche ◽  
G. Camiré
Keyword(s):  
Chemical Weathering ◽  
Volcanic Rocks ◽  
Source Area ◽  
Source Rocks ◽  
Iron Formation ◽  
Mining District ◽  
Metasedimentary Rocks ◽  
Clastic Rocks ◽  
The North ◽  
Volcanic Source

The Archean Golden Pond sequence is made up of deformed and metamorphosed conglomerates, greywackes, and mafic volcanic rocks, and is overlain by ferrugineous metasedimentary rocks of the North iron formation. The clastic rocks were derived mainly from a volcanic source that had undergone weak chemical weathering. Their source area was dominated by the presence of 60–80% high-Al2O3 felsic volcanics having strongly fractionated [La/Sm]N (= 3.7 ± 0.3) and very low Ta/Th ratios (= 0.09 ± 0.02), with lesser proportions of basaltic (10–30%) and ultramafic volcanic rocks (1–10%). The ferrugineous metasedimentary rocks can be modelled by mixing 20–40% siliciclastic material, of the composition of the average Golden Pond greywacke, with an Fe- and Si-rich precipitate (molecular Fe/Si = 0.6 ± 0.2). The high-Al2O3 felsic source rocks were most likely produced by subduction processes within an oceanic arc environment, but the mafic and ultramafic volcanic rocks were derived by different processes from an asthenospheric mantle source, possibly in an oceanic rift environment. Therefore, it is suggested that the ultramafic, mafic, and felsic volcanic rocks were brought to the same erosional level by dissection of the arc system and rapid exhumation of the felsic arc lithologies and the deeper ocean floor. Intrabasinal hydrothermal activity associated with contemporaneous mafic volcanism and (or) graben development may have also been responsible for the local production of the Fe-rich precipitates of the North iron formation.

scholarly journals New insights on the occurrence of peperites and sedimentary deposits within the silicic volcanic sequences of the Paraná Magmatic Province, Brazil

2013 ◽  
Vol 5 (2) ◽  
pp. 2313-2344 ◽  
Author(s):  
A. C. F. Luchetti ◽  
A. J. R. Nardy ◽  
F. B. Machado ◽  
J. Madeira ◽  
J. M. Arnosio
Keyword(s):  
Environmental Conditions ◽  
Volcanic Rocks ◽  
Unconsolidated Sediments ◽  
Southeastern Brazil ◽  
Basaltic Lava ◽  
Sedimentary Deposits ◽  
Arid Conditions ◽  
Volcanic Events ◽  
Silicic Volcanic ◽  
New Evidence

Abstract. In the Paraná Basin (southern and southeastern Brazil), the stratigraphy of the Paraná Magmatic Province (PMP) is composed of a thick (up to 1600 m) volcanic sequence formed by a succession of petrographically and geochemically distinct units of basic and acidic composition. The whole package may have been emplaced in approximately 3 million yr of almost uninterrupted activity. A few aeolian sandstone layers, indicating arid environmental conditions (Botucatu Formation), are interlayered in the lower basalts. Above the basalts, the Palmas and Chapecó Members of the Early Cretaceous Serra Geral Formation, are composed of silicic volcanic rocks (trachydacites, dacites, rhyolites, and rhyodacites) and basalts. This paper presents new evidence of episodes of sedimentation separating silicic volcanic events, expressed by occurrences of sedimentary deposits. Interaction between the volcanic bodies and the coeval unconsolidated sediments formed peperites. The sediments were observed between basaltic lava flows and silicic rocks or interlayered in the Palmas type rocks, between Chapecó type rocks and underlying basaltic flows, between silicic bodies of Palmas and Chapecó types, and interlayered with Palmas type units. The observed structures indicate that the sediments were still wet and unconsolidated, or weakly consolidated, at the time of volcanism, which coupled with the sediment features reflect environmental conditions that are different from those characterizing the Botucatu arid conditions.

scholarly journals Petrographic and geochemical interpretations of source provenance and tectonic setting of the Lokoja Sandstone, Bida Basin, Nigeria

2020 ◽  
Vol 8 (2) ◽  
pp. 279
Author(s):  
G. U. Ozulu ◽  
A. U. Okoro ◽  
V. O. Ndubueze
Keyword(s):  
Trace Elements ◽  
Inductively Coupled Plasma ◽  
Tectonic Setting ◽  
Source Area ◽  
Climatic Conditions ◽  
Source Rocks ◽  
Heavy Minerals ◽  
Petrographic Analysis ◽  
Moderate Degree ◽  
X Ray

The petrography and geochemistry of major and trace elements distribution pattern for the Lokoja Sandstones, Southern Bida Basin, Nigeria; were used to interpret their provenance, weathering conditions and paleotectonic setting. A total of seven (7) representative sandstone samples were selected for petrographic, heavy minerals and inorganic geochemical analyses; that is X- ray diffraction (XRD), X-ray fluorescence (XRF) and Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). Results of the petrographic analysis showed 52.14 % quartz, 39.29 % feldspar, 2.00 % rock fragments, 5.14 % matrix and cement fraction as well as 1.43 % unfilled voids. Results of major elements and oxides suggests intermediate to felsic source rocks while the dominance of Na-rich feldspar to the k-feldspar and high value of Fe2O3+MgO shows contribution from ferromagnesian minerals of mafic igneous source provenance and oceanic island arc region. Average concentrations of designated trace elements in the studied sandstones are low in concentrations. The lower concentrations of Cr, Co, and Ni and higher concentrations of Zr, Ba, and Sr suggest a felsic progenitor rock. But significantly high values of Ni (7.02 ppm), La/Co (7.99), and Ni/Co (3.28) as well as the low concentration value of Y, (3.23 ppm) suggests contributions from mafic source rocks. Low average ratios for La/Co, Th/Co, Th/Sc, Ni/Co, Cr/Ni, Cr/Sc, Cr/Th, Ni/Co, Cr/Ni, Cr/Th, Cr/Sc, Th/Sc, La/Co and Th/Co also suggest a felsic source provenance. An average CIA value of 78.04% is indicative of an intense recycling in the source area while an average MIA value of 56.13% suggests a moderate degree of weathering. The high clay matrix and feldspar content have been used to classify the sandstones as feldspathic greywackes deposited in dry arid climatic conditions under a basement uplifted tectonic setting.   

Spatial and Temporal Variations in the Geochemistry of Cauvery River (Tamil Nadu, India) Sediments and its Implication to Weathering

2020 ◽  
Vol 37 (2) ◽  
pp. 49-60
Author(s):  
R Nagendra ◽  
L Elango ◽  
K Vybhav
Keyword(s):  
Tamil Nadu ◽  
Chemical Weathering ◽  
River Sediment ◽  
River Sediments ◽  
Temporal Variations ◽  
Source Rocks ◽  
Sediment Geochemistry ◽  
Cauvery River ◽  
Post Monsoon ◽  
North East

South-West (SW), North-East (NE) and Post-monsoon Cauvery River sediment geochemistry characterizes the intensity of chemical weathering ascribing to the relative mobility of elements during weathering. The negative correlation between Al2O3% and SiO2% signifies that the sediments are enriched with quartz and, Al2O3% vs. TiO2% relationship deduces the granite and granodiorite are the major source rocks of Cauvery River sediment. The weathering trend of Cauvery River sediments is accounted by the incidence of illite clay minerals. The weathering intensity of SW monsoon sediments (57.73%), NE monsoon sediments (64.17%) and post-monsoon sediments (64.79%) specifies the weak to intermediate intensity of weathering, which is controlled by precipitation. The higher concentration of Ba (459.45-856.95ppm) symbolises the presence of K-feldspar. 

Sign in / Sign up

Export Citation Format

Share Document