Clay minerals of late Pleistocene sites (Jonzac and Les Cottés, SW France): Applications of X-ray diffraction analyses to local paleoclimatic and paleoenvironmental reconstructions

2013 ◽  
Vol 302 ◽  
pp. 184-198 ◽  
Author(s):  
Marine Frouin ◽  
Florian Ploquin ◽  
Marie Soressi ◽  
William Rendu ◽  
Roberto Macchiarelli ◽  
...  
1962 ◽  
Vol 42 (2) ◽  
pp. 296-301 ◽  
Author(s):  
J. S. Clark ◽  
J. E. Brydon ◽  
H. J. Hortie

X-ray diffraction analysis was used to identify the clay minerals present in fourteen subsoil samples that were selected to represent some more important clay-bearing deposits in British Columbia. The clay mineralogy of the subsoils varied considerably but montmorillonitic clay minerals tended to predominate in the water-laid deposits of the south and illite in the soil parent materials of the Interior Plains region of the northeastern part of the Province.


2021 ◽  
Vol 13 (2) ◽  
pp. 601-610
Author(s):  
K. Itiowe ◽  
R. Oghonyon ◽  
B. K. Kurah

The sediment of #3 Well of the Greater Ughelli Depobelt are represented by sand and shale intercalation. In this study, lithofacies analysis and X-ray diffraction technique were used to characterize the sediments from the well. The lithofacies analysis was based on the physical properties of the sediments encountered from the ditch cuttings.  Five lithofacies types of mainly sandstone, clayey sandstone, shaly sandstone, sandy shale and shale and 53 lithofacies zones were identified from 15 ft to 11295 ft. The result of the X-ray diffraction analysis identified that the following clay minerals – kaolinite, illite/muscovite, sepiolite, chlorite, calcite, dolomite; with kaolinite in greater percentage. The non-clay minerals include quartz, pyrite, anatase, gypsum, plagioclase, microcline, jarosite, barite and fluorite; with quartz having the highest percentage. Therefore, due to the high percentage of kaolinite in #3 well, the pore filing kaolinite may have more effect on the reservoir quality than illite/muscovite, chlorite and sepiolite. By considering the physical properties, homogenous and heterogeneous nature of the #3 Well, it would be concluded that #3 Well has some prospect for petroleum and gas exploration.


1999 ◽  
Vol 63 (6) ◽  
pp. 801-812 ◽  
Author(s):  
L. Quattropani ◽  
L. Charlet ◽  
H. de Lumley ◽  
M. Menu

AbstractBones from level G in the Arago cave (Tautavel, Southern France, 450 ky) were analysed using a combination of particle induced X-ray and gamma-ray emission (PIXE and PIGME) and X-ray diffraction (XRD). Human occupation and guano production by bats introduced a large amount of phosphate into the cave and as a result a decarbonated pocket was formed in the sediment, characterized by the dissolution of clay minerals, calcite and bones, and by the precipitation of phosphate secondary minerals. The Al released by clay minerals was reprecipitated as crandallite in the few remaining bones, and as montgomeryite with traces of crandallite in the surrounding sediments. Bones within the pocket have very high levels of Al, Fe, F and Zn and often have ‘diffusive’ type U-shaped concentration profiles. These profiles show that post-mortem uptake of trace elements occurred, and thus that trace element composition has to be used with care in palaeonutritional studies but is indicative of local palaeoenvironment. This uptake is complicated by a large increase in hydroxylapatite crystallinity in Palaeolithic bones compared to modern or more recent ones, as a result of the large P influx which occurred in the Arago cave after the sediment deposition.


2012 ◽  
Vol 78 (2) ◽  
pp. 353-362 ◽  
Author(s):  
Torben C. Rick ◽  
John S. Wah ◽  
Jon M. Erlandson

AbstractAt the close of the Pleistocene, fire regimes in North America changed significantly in response to climate change, megafaunal extinctions, anthropogenic burning and possibly, even an extraterrestrial impact. On California's Channel Islands, researchers have long debated the nature of late Pleistocene “fire areas,” discrete red zones in sedimentary deposits, interpreted by some as prehistoric mammoth-roasting pits created by humans. Further research found no evidence that these red zones were cultural in origin, and two hypotheses were advanced to explain their origin: natural fires and groundwater processes. Radiocarbon dating, X-ray diffraction analysis, and identification of charcoal from six red zones on Santa Rosa Island suggest that the studied features date between ~ 27,500 and 11,400 cal yr BP and resulted from burning or heating, not from groundwater processes. Our results show that fire was a component of late Pleistocene Channel Island ecology prior to and after human colonization of the islands, with no clear evidence for increased fire frequency coincident with Paleoindian settlement, extinction of pygmy mammoths, or a proposed Younger Dryas impact event.


Minerals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 718
Author(s):  
Isis Armstrong Dias ◽  
Leonardo Fadel Cury ◽  
Bruno Guimarães Titon ◽  
Gustavo Barbosa Athayde ◽  
Guilherme Fedalto ◽  
...  

Mg clay minerals are usually associated with carbonates in alkaline-saline environments, precipitated from solution and/or transformation from other minerals. The aim of this research is to identify the mineralogy and geochemistry of clay minerals in different alkaline lakes in the Nhecolândia region, the southernmost region of the Pantanal wetland (Brazil). Sediment samples were analyzed by X-ray diffraction, X-ray fluorescence, scanning electron microscopy and transmission electron microscopy. Water samples were analyzed, determining their main cations and anions, in order to understand their relationship with the clays. The analyses allowed classifying the water bodies as saline, oligosaline and freshwater lakes. The sediments are composed mainly of quartz and a fine-clay fraction, dominated by illite, kaolinite and smectite. The XRD results showed illite and smectite mixed-layered in the saline lakes at Barranco Alto farm, whereas at Nhumirim farm, trioctahedral smectite was only observed in one lake. The smectite minerals were normally identified coupled with calcite at the top of the sequences, associated with exopolymeric substances (EPS) in the lakes, suggesting that these minerals are precipitating due to the physical-chemical and biological conditions of the water bodies.


Clay Minerals ◽  
1992 ◽  
Vol 27 (4) ◽  
pp. 435-444 ◽  
Author(s):  
T. J. Bandosz ◽  
J. Jagiełło ◽  
K. A. G. Amankwah ◽  
J. A. Schwarz

AbstractModification of clay minerals by exchange, intercalation, calcination and imbibition of organics followed by their polymerization and carbonization was studied. The surface properties of the clays were investigated by inverse gas chromatography at infinite dilution employing alkanes and alkenes as probes; the structural properties were measured directly by X-ray diffraction and inferred from the results of high pressure hydrogen adsorption. Calcination of pillared smectites prior to polymerization and carbonization of organic material in the interlayer space leads to a microporous “activated carbon” that demonstrates unique properties as an adsorbent for hydrogen, significantly different from clays that have not been calcined.


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