Chemical weathering on the Carnmenellis granite

1973 ◽  
Vol 39 (304) ◽  
pp. 429-447 ◽  
Author(s):  
C. M. Rice
Keyword(s):  
Trace Elements ◽  
Chemical Weathering ◽  
Mineralogical Composition ◽  
Major And Trace Elements ◽  
Weathering Profile ◽  
Normal Behaviour ◽  
Secondary Minerals ◽  
Low Degree ◽  
Bulk Chemical ◽  
Mineral Changes

SummaryThe behaviour of 25 major and trace elements, together with mineral changes, has been examined in a deep weathering profile on the Carnmenellis granite, Cornwall. The bulk chemical and mineralogical composition of the regolith shows only minor changes from the parent rock indicating a low degree of chemical weathering. However, within the regolith marked differences occur between the fine fractions from the various horizons. Chlorite and degraded muscovite characterize the fines of horizons A+B and C whereas gibbsite and kaolinite characterize horizon D. Secondary minerals becoming base deficient with depth is the reverse of normal behaviour and two possible theories are advanced to explain this anomaly. Most of the trace elements are concentrated in the < 10 µm fraction of the various horizons, in part by an association with degraded muscovite. Tin and Zr occur in resistates and Be, Sr, and Co are mainly lost during weathering.

scholarly journals Provenance and weathering index of the Upper Cretaceous São Carlos Formation and its tectonic significance in the eastern Bauru Basin, SE Brazil

2019 ◽  
Vol 19 (3) ◽  
pp. 77-94
Author(s):  
Lara Ferreira Neves ◽  
Alessandro Batezelli
Keyword(s):  
Trace Elements ◽  
Chemical Weathering ◽  
Upper Cretaceous ◽  
Source Area ◽  
Sedimentary Basins ◽  
Major And Trace Elements ◽  
Published Data ◽  
Weathering Index ◽  
Se Brazil ◽  
Eastern Border

Geochemistry of major and trace elements has been used as an important tool for the study of provenance and tectonic and climatic evolution of sedimentary basins. The São Carlos Formation is an Upper Cretaceous unit that lies on the eastern border of the Bauru Basin. Despite the paleontological and paleodepositional studies performed in this unit in the last years, little is known about the correspondence between tectonic and climatic conditions acting during the first stages of sedimentation. The hypothesis of this paper is to evaluate São Carlos and Araçatuba formations and understand the evolution of the eastern border of the basin. Thus, were conducted geochemical studies using X-ray fluorescence on sandstones, siltstones, and shales from the São Carlos Formation. According to the chemical weathering index, which presented values ranging from 57.12 to 71.58%, the oxides of major elements indicate that moderate weathering processes affected the source area, possibly associated with the arid-semiarid climate. Alkaline rocks, granites, gneisses, and metasediments were the main lithotypes of the source area. Ternary diagrams show that the tectonic environment was equivalent to the passive continental margin, coinciding with the Serra do Mar and, secondarily, Alto Paranaíba Uplift regions. Based on major and trace elements, their ratios, and published data on the basin, was elaborated a paleogeographic model of the eastern border of the Bauru Basin, concluding that the source area of the sediments was constituted by intermediate and felsic rocks, sometimes recycled by sedimentary processes.

Mineralogical norm calculations applied to tropical weathering profiles

1997 ◽  
Vol 61 (405) ◽  
pp. 185-196 ◽  
Author(s):  
G. Voicu ◽  
M. Bardoux ◽  
D. Voicu
Keyword(s):  
South America ◽  
Chemical Weathering ◽  
Visual Basic ◽  
Metamorphic Rocks ◽  
Chemical Analyses ◽  
Calculation Methods ◽  
Weathering Profile ◽  
Calculation Algorithm ◽  
Secondary Minerals ◽  
Tropical Weathering

AbstractIn contrast with igneous and metamorphic rocks, classical petrochemical calculation methods cannot be used for tropical weathering components (saprolite, bauxitic, ferruginous, siliceous and calcareous laterite) in converting whole-rock chemical analyses into normative mineralogical weight percentages. Weathering profiles are characterized by a mixture of primary and secondary minerals, which are not considered in the classical methods of mineralogical norm calculation. A new petrochemical calculation algorithm is proposed for the conversion of whole-rock chemical analyses into weathering norm (WN) for several components of the tropical weathering profiles. The normative minerals are represented by three primary minerals, six secondary minerals, four primary/secondary mineral pairs, and five minerals which can have both primary and secondary origin. This algorithm has been used in MINNOR, a WINDOWS application written in Visual Basic, which calculates the mineralogical norm. In order to test the program, several types of different chemical weathering profiles from South America and Africa have been selected. Special attention is paid to the weathering profile from Omai, Guyana, South America.

The Origin of Garnets in the Borrowdale Volcanic Series and Associated Rocks, English Lake District

1956 ◽  
Vol 93 (2) ◽  
pp. 121-139 ◽  
Author(s):  
R. L. Oliver
Keyword(s):  
Trace Elements ◽  
Physical Properties ◽  
Small Variation ◽  
Mineralogical Composition ◽  
Major And Trace Elements ◽  
Lake District ◽  
Intrusive Rocks ◽  
English Lake District ◽  
Volcanic Series ◽  
Chemical Evidence

AbstractAlmandine-rich garnets occur as euhedral crystals in extrusive and intrusive rocks which range in composition from 59 per cent, to 70 per cent. SiO2. Eight complete garnet analyses (major and trace elements) indicate a small variation in composition which, together with corresponding variation of physical properties, appear to correlate with the mineralogical composition of the containing rock. Field, microscopic and chemical evidence suggests, on balance, that the garnets are pyrogenetic. Magmatic conditions suitable for the crystallisation of almandine-rich garnet are discussed.

Applications of SEM/EDXA in cement clinker investigation

1990 ◽  
Vol 48 (4) ◽  
pp. 870-871
Author(s):  
Arezki Tagnit-Hamou ◽  
Shondeep L. Sarkar
Keyword(s):  
Mineralogical Composition ◽  
Physicochemical Characteristics ◽  
Cement Clinker ◽  
Accurate Information ◽  
Phase Identification ◽  
History Of ◽  
Bulk Chemical ◽  
Resolution Imaging ◽  
Proven Method ◽  
Instantaneous Chemical

All the desired properties of cement primarily depend on the physicochemical characteristics of clinker from which the cement is produced. The mineralogical composition of the clinker forms the most important parameter influencing these properties.Optical microscopy provides reasonably accurate information pertaining to the thermal history of the clinker, while XRDA still remains the proven method of phase identification, and bulk chemical composition of the clinker can be readily obtained from XRFA. Nevertheless, all these microanalytical techniques are somewhat limited in their applications, and SEM/EDXA combination fills this gap uniquely by virtue of its high resolution imaging capability and possibility of instantaneous chemical analysis of individual phases.Inhomogeneities and impurities in the raw meal, influence of kiln conditions such as sintering and cooling rate being directly related to the microstructure can be effectively determined by SEM/EDXA. In addition, several physical characteristics of cement, such as rhcology, grindability and hydraulicity also depend on the clinker microstructure.

Major and Trace Elements in the Humic Acid

2018 ◽  
Author(s):  
Zoltán Kis ◽  
Katalin Gméling ◽  
Tímea Kocsis ◽  
János Osán ◽  
Mihály András Pocsai ◽  
...  
Keyword(s):  
Trace Elements ◽  
Humic Acid ◽  
Activation Analysis ◽  
Analytical Techniques ◽  
Major And Trace Elements ◽  
Prompt Gamma Activation Analysis ◽  
Prompt Gamma ◽  
Gamma Activation ◽  
X Ray ◽  
Precise Analysis

We present precise analysis of major and trace elements of the humic acid. We used three different element analytical techniques in our investigations as prompt-gamma activation analysis (PGAA), neutron activation analysis (NAA) and X-ray fluorescence (XRF) analysis was carried out. We identified 42 elements in our sample.

A review of major and trace elements in Nile River and Western Red Sea sediments: An approach of geochemistry, pollution, and associated hazards

2021 ◽  
Vol 170 ◽  
pp. 109595
Author(s):  
Wael M. Badawy ◽  
Octavian G. Duliu ◽  
Hussein El Samman ◽  
Atef El-Taher ◽  
Marina V. Frontasyeva
Keyword(s):  
Trace Elements ◽  
Red Sea ◽  
Major And Trace Elements ◽  
Nile River
Sign in / Sign up

Export Citation Format

Share Document