PROVENANCE, TEXTURE, AND RELATIVE AGE CONTROLS ON THE CHEMICAL INDEX OF ALTERATION (CIA) IN PLEISTOCENE TILLS, MINNESOTA USA

2018 ◽  
Author(s):  
Chad Wittkop ◽  
◽  
Christian Piper ◽  
Julie K. Bartley ◽  
Russell Krueger ◽  
...  
Keyword(s):  
Relative Age ◽  
Chemical Index ◽  
Chemical Index Of Alteration

scholarly journals Provenance of sediments from Barra del Tordo and Tesoro beaches, Tamaulipas State, northwestern Gulf of Mexico

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Mayla A. Ramos-Vázquez ◽  
John S. Armstrong-Altrin
Keyword(s):  
Gulf Of Mexico ◽  
Age Groups ◽  
Source Area ◽  
Detrital Zircons ◽  
Sediment Provenance ◽  
Geochemical Composition ◽  
Chemical Index ◽  
Beach Sediments ◽  
Chemical Index Of Alteration ◽  
Ree Patterns

AbstractThe mineralogy, bulk sediment geochemical composition, and U–Pb ages of detrital zircons retrieved from the Barra del Tordo (Tordo) and Tesoro beach sediments in the northwestern Gulf of Mexico were analyzed to determine their provenance. The beach sediments are mainly composed of quartz, ilmenite, magnetite, titanite, zircon, and anorthite. The weathering proxies such as the Chemical Index of Alteration (CIA), Chemical Index of Weathering (CIW), and Plagioclase Index of Alteration (PIA), reveal a moderate-to-high intensity of weathering in the source area. The chondrite-normalized rare earth element (REE) patterns are similar to felsic igneous rocks, with large negative europium anomaly (Eu/Eu* = ~ 0.47–0.80 and ~ 0.57–0.67 in the Tordo and Tesoro beach sediments, respectively).Three major zircon U–Pb age groups are identified in the Tordo and Tesoro beach sediments, i.e., Proterozoic (~ 2039–595 Ma), Mesozoic (~ 244–70.3 Ma), and Cenozoic (~ 65.9–1.2 Ma). The differences of the zircon age spectrum between the Tordo and Tesoro beach sediments are not significant. The comparison of zircon U–Pb ages in this study with ages of potential source terranes suggests that the Mesozoic and Cenozoic zircons of the studied Tordo and Tesoro beach sediments were derived from the Eastern Alkaline Province (EAP) and Mesa Central Province (MCP). Similarly, the likely sources for the Proterozoic zircons were the Sierra Madre Oriental (SMOr) and Oaxaquia in the northwestern Gulf of Mexico. The results of this study further indicate that the sediments delivered to the beaches by rivers and redistributed by longshore currents were crucial in determining the sediment provenance.

scholarly journals X-RAY FLUORESCENCE AND STABLE ISOTOPES ANALYSES OF IKPESHI MARBLE, SOUTH SOUTHERN NIGERIA

2020 ◽  
Vol 10 ◽  
pp. 102
Author(s):  
Phillips Reuben Ikhane ◽  
Olalekan Olayiwola Oyebolu ◽  
Afolabi Omotayo Alaka
Keyword(s):  
Stable Isotopes ◽  
Stable Isotope ◽  
Precipitation Process ◽  
Dolomitic Marble ◽  
X Ray ◽  
Humid Condition ◽  
Major Oxides ◽  
Chemical Index ◽  
Isotopic Analyses ◽  
Chemical Index Of Alteration

Integration of X-ray fluor escence and stable isotope spectrometric techniques for quality assessment and provenance study of exposed marble deposit at Fakunle Quarry, Ikpeshi, South Western Nigeria constitute the fundamental aims of this research. Fourteen fresh (14) marble samples obtained at different localities within the quarry were subjected to geochemical and isotopic analyses to ascertain the quantitative abundance of major oxides and stable isotopes using X-Ray Fluorescence and Thermo Fisher mass spectrometer respectively. The major oxides revealed by XRF analysis of the marble samples are CaO, MgO, SiO2, Al2O3, Fe2O3 and Na2O with percentage composition ranging between 11.66 – 13.25, 7.75 – 9.65, 41.36 – 47.55, 12.36 – 15.23, 7.79 – 10.55 and 1.44 – 1.75respectively. Na2O + K2O value ranges between 1.48 and 1.78.The classification of marble in relation to percentage of calcite-dolomite indicate a percentage range of -5 to 4% and 93-103% for Calcite and Dolomite respectively. Chemical Index of Alteration (CIA) ranges from 45.16 to 51.59 % and Chemical Index of Weathering (CIW) ranges from 46.19 to 52.30 %. Stable isotope ( ? –180) of marble ranges from -10.50 to -7.00 with a corresponding value from 25.50 to 55.33.Interpretation of the overall results indicates an impure quartz-rich dolomitic marble; metamorphosed from a low carbonate sedimentary/meta sedimentary protolith which shallowly precipitated within a passive marginal marine environment under humid condition. The high silica impurity can however be attributed to the inordinate influx of terrigenous sediments during the precipitation process. Weathering effect is minimal on the marble deposit. Conclusively, strong correlation is apparent between the obtained geochemical result and the basement geology of the study area.

Variation of chemical index of alteration (CIA) in the Ediacaran Doushantuo Formation and its environmental implications

2020 ◽  
Vol 347 ◽  
pp. 105829
Author(s):  
Can Chen ◽  
Jiasheng Wang ◽  
Zhou Wang ◽  
Yongbo Peng ◽  
Xiaohong Chen ◽  
...  
Keyword(s):  
Environmental Implications ◽  
Doushantuo Formation ◽  
Chemical Index ◽  
Chemical Index Of Alteration

Kaolin in the net-like horizon of laterite in Hubei, south China

Clay Minerals ◽  
2009 ◽  
Vol 44 (1) ◽  
pp. 51-66 ◽  
Author(s):  
Hanlie Hong ◽  
Zhaohui Li ◽  
Muzhuang Yang ◽  
Ping Xiao ◽  
Huijuan Xue
Keyword(s):  
Electron Microscopy ◽  
South China ◽  
Energy Dispersive Spectrometer ◽  
Clay Mineralogy ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Chemical Index ◽  
Mineral Components ◽  
Chemical Index Of Alteration ◽  
Matrix Components

AbstractThe clay mineralogy and chemical composition of the white veins, red matrix and both Fe- and Mn-bearing nodules occurring in a laterite profile in Hubei, south China were investigated using X-ray diffraction, scanning electron microscopy equipped with an energy-dispersive spectrometer, and high-resolution transmission electron microscopy. The results show that the mineral components of the red matrix are mainly quartz, kaolinite, halloysite, goethite and minor illite, whereas the white net-like veins contain mostly quartz, kaolinite, halloysite, and illite. In the net-like horizon, the chemical index of alteration (CIA, the ratio of Al2O3/(Al2O3+CaO+K2O+Na2O)) and the TiO2/Al2O3 ratio are 89.8% and 0.021 for the white vein and 90.7% and 0.025 for the red matrix, respectively. Both white-vein and red-matrix components have similar TiO2/Al2O3 ratios, and are similar to the ratio 0.027 of the unaltered bedrock. The similarity in TiO2/Al2O3 values indicates that all three portions of the laterite soil share the same origin. Also, although the white-vein and red-matrix components differ in Fe2O3 abundance, the similar CIA values do imply similar degrees of alteration. The Fe-bearing and Mn-bearing nodules were produced by the local accumulation of Fe2O3 and MnO, respectively. Halloysite in the weathering profile occurs in two different morphologies, tubular and platy crystals. Tubular halloysite occurs both in the red matrix and the Fe-bearing nodule whereas platy halloysite occurs only in the white vein and Mn-bearing nodule assemblages. Crystallization of small tubular halloysite from Si and Al concretions in the red matrix is observed, indicating that the morphology of these crystals in the weathering environment is mainly controlled by Fe3+ cations, whereas platy halloysite may be derived from the hydration of kaolinite.

The weathering intensity scale (WIS): An alternative approach of the Chemical Index of Alteration (CIA)

2013 ◽  
Vol 313 (2) ◽  
pp. 113-143 ◽  
Author(s):  
A. Meunier ◽  
L. Caner ◽  
F. Hubert ◽  
A. El Albani ◽  
D. Pret
Keyword(s):  
Intensity Scale ◽  
Chemical Index ◽  
Alternative Approach ◽  
Weathering Intensity ◽  
Chemical Index Of Alteration

Geochemical trends through time and lateral variability of diatom floras in the Pleistocene Olorgesailie Formation, southern Kenya Rift Valley

2011 ◽  
Vol 76 (1) ◽  
pp. 167-179 ◽  
Author(s):  
R. B. Owen ◽  
R. W. Renaut ◽  
R. Potts ◽  
A. K. Behrensmeyer
Keyword(s):  
Soil Erosion ◽  
Human Evolution ◽  
Deep Water ◽  
Shallow Lakes ◽  
Temporal Variability ◽  
Kenya Rift ◽  
Chemical Index ◽  
Chemical Index Of Alteration ◽  
S Peak ◽  
Fossil Hominin

AbstractThe Olorgesailie Formation (1.2–0.49 Ma) consists of fluvial and lacustrine rift sediments that have yielded abundant Acheulean artifacts and a fossil hominin (Homo cf. erectus). In testing prior understandings of the paleoenvironmental context, we define nine new geochemical zones. A Chemical Index of Alteration suggests increased catchment weathering during deposition of Members 1, 2, 7, 11, and 13. Biophile elements (Br, S) peak in M8–9 and lower M13 possibly reflecting increased input from soil erosion. REE data show that the Magadi Trachytes supplied most siliciclastic grains. Sixteen diatom stages indicate conductivities of 200–16,000 μS cm− 1 and pH of 7.5–9.5 for five deep-water lakes, ten shallow lakes and sixteen wetlands. These results are compared with diatom data from other sections in the basin and show aquatic spatial variability over km-scale distances. Similar floras are traceable over several kilometers for M2, M3 and M9, indicating broadly homogeneous lacustrine conditions during these times, but diatoms in other members imply variable conditions, some related to local tectonic controls. This lateral and temporal variability emphasizes the importance of carrying out stratigraphic sampling at multiple sites within a basin in efforts to define the environmental context relevant to human evolution.

scholarly journals Geochemical and petrographic characteristics of sediments along the transboundary (Kenya–Tanzania) Umba River as indicators of provenance and weathering

2021 ◽  
Vol 13 (1) ◽  
pp. 1064-1083
Author(s):  
Amon Kimeli ◽  
Oliver Ocholla ◽  
Judith Okello ◽  
Nico Koedam ◽  
Hildegard Westphal ◽  
...  
Keyword(s):  
River Sediments ◽  
East African ◽  
African Region ◽  
Chemical Index ◽  
Chemical Index Of Alteration ◽  
East African Region ◽  
The Indian Ocean ◽  
Cenozoic Sediments ◽  
High Degree ◽  
Mineralogical Compositions

Abstract The Umba River basin is one of the smaller-scale hydrological basins in the East African region. It traverses two countries, with its catchment in the Usambara mountains in Tanzania, while it drains its waters to the Indian Ocean in Vanga, Kenya. The chemical and mineralogical compositions of the riverbank and bottom sediments of the Umba River were analyzed and evaluated to describe their source characteristics and provenance. The dominant minerals include quartz, K-feldspars, plagioclase, hornblende, pyroxenes, muscovite, biotite, and likely presence of clays such as kaolinite. The chemical index of alteration of the sediments indicate a moderate to high degree of alteration. They reflect a dominant mafic to intermediate igneous provenance consistent with the geology of the Umba River catchment that is characterized by the outcrops of the granitic Precambrian basement and the quartz-dominated Paleozoic Karoo Supergroup, overlain by Mesozoic and Cenozoic sediments dominated by both mafic and felsic minerals. The similarity of the chemical and mineralogical compositions of the Umba River sediments from source to mouth further indicates a uniform source in the upper course of the river and only subordinate contributions from the lower course where it passes the Karoo and the younger sediments.

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