Clay Mineralogy and Occurrence of Ferrian Smectites Between Serpentinite Saprolites and Basalts in Biga Peninsula, Northwest Turkey

Abstract

Abstract--The clay mineralogy of an oxisol-saprolite overlying serpentinite and underlying basalt was studied with different techniques to evaluate the clay mineral transformation that occurred and to understand the origin of Fe3+-rich smectite. The saprolite zone of the oxisol, up to 30 m thick, contains smectites of the montmorillonite-beidellite and montmorillonite-nontronite series, as well as illite, chlorite, talc, and goethite or amorphous oxyhydrates. Illite is mainly concentrated in the upper 50 cm thick zone underlying the basalt layer and chlorite-content increases toward altered serpentinite at the base. Minor amounts of nontronite formed mostly toward westward exposures where the hot contact layer between serpentinite and basalt is only 20 cm thick. Greene-Kelly Li-tests revealed that all samples contain montmorillonite, but one sample shows the presence of a minor amount of beidellite.Parent rocks are a mixture of mainly mica schist (the source of beidellite), and minor serpentinite in different percentages and laterally distributed. These rocks were intensely weathered under humid climatic conditions. Silica was concentrated as amorphous transparent (pure silica) cobbles and milky quartz pebbles, and originated from geothermal solutions rising through the Ovaclk thrust fault. The Mg partly formed chlorite. Ferrian smectites in serpentinites were derived obviously from the Mg-rich minerals but Mg is lost much more rapidly than Si during the formation of the clay deposit. The structural formula of the most Fe-rich smectite samples from the study area is (5i6.60~7.10 All.o~0~)(Alzsn_J.2~Mg0.32_0.92Fe~+Hs_l.68-Ti0a6_004)(Ca016_010Na002K002_ 0.12)O20(OH)4. This composition is within the range recorded for the ferrian montmorillonite-beidellite series, with very little vermiculite forming the oxisol-vertisol horizon.

Hydrothermal Alteration on Composite Volcanoes: Mineralogy, Hyperspectral Imaging, and Aeromagnetic Study of Mt Ruapehu, New Zealand

“…The presence of phyllosilicates is often as fracture infilling minerals, showing thin crystallites with a vermiform, fibrous, and tubular morphologies with hollow interiors, with Mg and Fe enrichment (Figure 5b). These textural and morphological features also indicate smectite group minerals (Beauchamps et al, 2019; Ece et al, 1999; Ta et al, 2017), indicating the dominance of montmorillonite and nontronite. Some samples (rh26) contain zeolite group minerals with acicular and radial crystal habits, occurring in fractures and cavity infilling.…”

Clay minerals as alteration products in basaltic volcaniclastic deposits of La Palma (Canary Islands, Spain)

“…For example, Pevear et al (1982), Mizota and Faure (1998), Shau and Peacor (1992), Christidis et al (1995), Arnouric et al (2000), Cuevas et al (2001), etc., suggest a hydrothermal origin for the genesis of smectites in volcanic deposits. On the other hand, Aoudjit et al (1995), Ece et al (1999), Minato (2000) and others describe clay minerals formed by chemical weathering of volcanic debris. Moreover, Grauby et al (1994), Roberson et al (1999), Kloprogge et al (1999), Huertas et al (2000), Drief et al (2001), Ramirez et al (1998), Fiore et al (2001) and others, show examples of clay minerals synthesized in the laboratory.…”

Nutrient Fluxes and Sediments Composition in El Mex Bay and Surround Drains, Alexandria, Egypt

“…A peak can be seen, especially at El-Mex and El-Qalaa around 2940 cm −1 could be attributed to the asymmetrical C-H stretching of methyl (-CH 2 ) groups being characteristic of aliphatic hydrocarbon [66]. The bands within the range of 780 -800 cm −1 represent the bending in plane vibration band of OH groups for δMgAlOH [67]. Carbonate minerals in all sediments are identified by the wave number of M-CO 3 stretching band within the range of 650 -700 cm −1 .…”

“…Carbonate minerals in all sediments are identified by the wave number of M-CO 3 stretching band within the range of 650 -700 cm −1 . The symmetric Si-O-Si stretching appeared as weak bands at 460 -500 cm −1 for Mariut and El Qalla drains sediment samples [67]. Tables 4-6 showed that the sediments comprise two main minerals: silicate and carbonate that appear in some sediments profile as Mg-calcite as a result of Mg substitution [68].…”