GROWTH OF KAOLINITE IN VITRICAL CLAYS IN THE BYTOM BASIN
Summary
Kaolinite is shown to be the major clay mineral in samples of clay and mudstone-clay karst rocks occurring in Triassic series in the Bytom Basin, Upper Silesia (so-called vitriol clays). It is also present but generally in much smaller amounts in unsoluble residuum of Triassic rocks, among which the described karst deposits occur.
SEM studies made it possible to state that omnipresent forms of occurrence of kaolinite include large (up to a few tenths of mm in size) crystals, book-, fan- or worm-like in outline. The mode of development of these crystals indicates that they have grown in the sediment. The in situ growth in plastic sediment is also shown by arrangement of minor plates of clay minerals along large kaolinite forms. Large kaolinite crystals are randomly distributed even in rock varieties displaying fine lamination.
Vitriol clays often yield even large amounts of authigenic Fe, Zn and Pb sulfides, the growth of which has been accompanying deposit-forming mineralization processes. However, any reliable data for reconstruction of time relations between the mineralization and growth of kaolinite are still not available. It may be assumed that kaolinite crystals were growing due to supply of solutions, the character of which remains difficult to decipher. The process could develop in result of either action of hydrothermal solutions responsible for low-temperature ore mineralization, or a synthesis of kaolinite. In both cases aluminasilicate minerals present in vitriol clays could act as the major source of substrata (Al, Si). Decay of these minerals under conditions of action of low-temperature solutions could be fairly rapid thanks to low pH ( due to action of inorganic or organic, i.e. humus or fulvic acids). The contribution of the latter in growth of kaolinite was also significant.
Abstract. Magnetic fraction of the atmospheric dust was collected in Kraków using a static sampler and analysed using several methods (scanning electron microscopy with energy dispersive spectrometry, transmission electron microscopy with energy dispersive spectrometry, X-ray diffraction, Mössbauer spectrometry, and vibrating sample magnetometer (VSM) measurements). The magnetic fraction contains magnetite, hematite and α-Fe, as well as quartz, feldspar and pyroxene. The magnetic particles vary in size from above 20 μm to nanoparticles below 100 nm, as well as in morphology (irregular or spherical). Their chemical composition is dominated by Fe, often with Mn, Zn, Cr, Cu, Si, Al, S, Ca and other elements. Mössbauer spectroscopy corroborates the composition of the material, giving further indication of smaller than 100 nm particles present in the atmospheric dust. VSM measurements confirm that the strength of the magnetic signal can be treated as a meter of the anthropogenic impact on the suspended particulate matter, once again highlighting the presence of nanoparticles.
Due to the increasing amount of produced and accumulated wastes, a potential source of elements might be the global waste stream coming from the waste incineration process. As a result of this process, bottom ash, fly ash and air pollution control residues are produced. The goal of this study was to evaluate the raw material potential of the anthropogenic materials which are fly ashes from municipal waste incineration and municipal sewage sludge incineration, and the possibility for the recovery of metallic or other economically valuable elements by comparison of their chemical composition with the chemical composition of Earth materials (ultramafic, mafic and felsic igneous rocks, various sedimentary rocks), and with their lowest content in currently exploited ores. Fly ashes contain more valuable and critical elements when compared to Earth materials; however, they are less concentrated in comparison to the content in currently exploited ores. Since natural resources are becoming depleted, the costs of exploitation, mineral processing and related operations are increasing and the fly ashes are easily accessible. Cheap materials do not demand complicated treatment which might be considered as a future source of P, Zn, Sn, Cr, Pb, Au and Ag, and thus fulfilling the assumptions of close-loop economy and to maximize natural resources protection.
Strefa wspolcześnie lewoprzesuwczego uskoku Dien Bien Phu (DBP), o orientacji NNE–SSW do N-S, jest jest jednym z najbardziej aktywnych uskokow sejsmotektonicznych w Indochinach. W NW Wietnamie uskok ten, 160 km dlugości i 6–10 km szerokości, przecina skaly osadowe i metamorficzne wieku poźnoproterozoicznego, paleozoicznego i mezozoicznego, a takze paleozoiczne i gornotriasowe granitoidy. Wzdluz DBP wystepuje 5 niewielkich basenow typu pull-apart (od polnocy: Pa Tan, Chan Nua, Lai Chau, Muong Pon oraz Dien Bien Phu), spośrod ktorych przeanalizowano szczegolowo dwa najwieksze, tj. Lai Chau i Dien Bien Phu. Oba baseny są obramowane przez uskoki lewoprzesuwcze i lewoprzesuwczo-normalne, wywolujące ugiecie i przemieszczenie sieci drenazu, obecnośc licznych grzbietow zagradzających (shutter ridges), jak rowniez zuskokowanie tarasow i stozkow naplywowych. Na obecnośc normalnej skladowej ruchu uskokowego wskazują: trojkątne lica progow uskokowych, wysoko wzniesione tarasy skalno-osadowe w przelomowych odcinkach dolin, zawieszone doliny oraz wysokie i niewyrownane spadki koryt rzecznych. Minimalne rozmiary przemieszczen lewoprzesuwczych wynoszą od 6–8 m do 20–50 m dla dolin holocenskich oraz 2–2,5 km dla dolin środkowo-poźnoplejstocenskich w roznych segmentach uskoku. Miązszośc osadow czwartorzedowych zmienia sie od kilku -, kilkunastu metrow w Lai Chau do blisko 130 m w basenie Dien Bien Phu.
W basenie Lai Chau osady tarasu średniego (23 m) rzeki Nam Na (stanowisko most Muong Te) zostaly wydatowane techniką OSL-SAR na 26–45 ka. Osady te zostaly przeciete uskokiem normalnym o zrzucie ok. 12 m w ciągu ostatnich 13 tys. lat i przykryte przez gliny stokowe, 8–12 m grubości, z kilkoma poziomami klinow koluwialnych z poziomami ostrokrawedzistego gruzu, a utworzonymi przypuszczalnie dzieki epizodom palesejsmicznym po dacie 13 ka. Kontakt miedzy utworami stokowymi a piaskowcami i mulowcami triasu rowniez ma charakter uskoku normalnego. W basenie Dien Bien Phu aluwia tarasow wczesno-środkowoholocenskich zostaly wydatowane OSL-SAR na 6,5-7 ka, podczas gdy najmlodsze pokrywy aluwialne zostaly zdeponowane 1,8–2,7 ka oraz niemal wspolcześnie. Aluwia gornoplejstocenskich stozkow naplywowych na wschodnim obramowaniu basenu są pociete serią spekan oraz drobnych uskokow o orientacji zbieznej z orientacją strefy DBP (N20oE).
Przemieszczone tarasy i stozki naplywowe pozwalają sądzic, iz minimalne tempo ruchu lewoprzesuwczego wynosilo 0,6–2 mm/rok w holocenie oraz 2–4 mm/rok w środkowym i poźnym plejstocenie. Natomiast tempo holocenskich ruchow wypietrzających zmienialo sie od 1 mm rocznie w rejonie Lai Chau do 0,4–0,6 mm/rok na zachod od Dien Bien Phu. Dlugoterminowe, średnie predkości czwartorzedowych ruchow podnoszących są trudne do oszacowania; przekraczaly one jednak wartośc 0,05 mm/rok.
YOUNG TECTONIC PROCESSES IN THE DIEN BIEN PHU FAULT ZONE, NW VIETNAM, IN THE LIGHT OF STUDIES OF QUATERNARY SEDIMENTS: PRELIMINARY REPORT
Summary
The Dien Bien Phu (DBP) fault zone, oriented NNE to N, is one of the most seismically active fault zones in Indochina. In NW Vietnam, this zone is 160 km long and 6–10 km wide, cutting through sedimentary and metamorphic rocks of the Late Proterozoic, Palaeozoic and Mesozoic age, as well as Palaeozoic and Upper Triassic granitoids. Along the DBP fault zone there occur relatively small, narrow pull-apart basins (from the north: Pa Tan, Chan-Nua, Lai Chau, Muong Pon, and Dien Bien Phu), the two largest of which (Lai Chau and Dien Bien Phu) have been studied in detail. Both are bounded by sinistral and sinistral-normal faults, responsible for offset and deflected drainage, presence of numerous shutter ridges and displaced terraces, and alluvial fans. The normal component of motion is testified to by well-preserved triangular facets on fault scarps, highly elevated straths in river watergaps, overhanging tributary valleys, as well as high and uneven river-bed gradients. Our observations indicate a minimum recent sinistral offset ranging from 6–8 m to 20–50 m for Holocene valleys to 2–2.5 km for middle-late Pleistocene valleys in different fault segments. The thickness of Quaternary sediments varies from a few to a dozen or so metres in Lai Chau to a few tens or even 130 m in DBP basin. In the Lai Chau basin, the middle terrace (23 m) alluvia of Nam Na River at Muong Te bridge, shortly north of the confluence with Song Da, have been OSL-SAR (optically-stimulated luminescence; single aliquot regenerative dose technique) dated to 26–45 ka. These sediments were normal-faulted by some 12 m after 13 ka, and mantled by vari-coloured slope loams, 8–12 m thick, containing colluvial wedges composed of angular debris. These wedges were probably formed due to at least two palaeoseismic events postdating 14–13 ka. The contact between slope sediments and Triassic bedrock is along a normal fault (N10oW, 78E), accompanied by 0.3–0.35- m-wide fault gouge. In the Dien Bien Phu basin, in turn, alluvium of the upper Holocene terrace has been OSL-SAR dated to 6.5–7 ka, whereas the younger terrace sediments give ages of 1.8–2.7 ka. Displaced terraces and alluvial fans allow us to suppose that the sinistral and sinistral-normal faults bounding narrow pull-apart basins in the southern portion of the DBP fault reveal minimum rates of left-lateral strike-slip ranging from 0.6 to 2 mm/yr in Holocene and 2–4 mm/yr in middle-late Pleistocene times, whereas rates of Holocene uplift tend to attain 1 mm/yr north of Lai Chau and 0.4–0.6 mm/yr west of Dien Bien Phu. Long-term, average Quaternary uplift rates are difficult to estimate, the minimum values certainly exceeding 0.05 mm/yr.
Abstract The influence of hydrological conditions and the pH of the environment on chlorite and mica transformations in the acidic weathering zone of pyrite-bearing schists was studied. Phyllosilicate transformations were investigated in the area of the abandoned pyrite open-pit mine in Wieściszowice (Lower Silesia, SW Poland) using X-ray diffractometry (XRD), Fourier transform infrared (FTIR) spectroscopy and chemical methods. (Mg, Fe)-chlorite, micas (muscovite and paragonite), quartz, feldspars and pyrite were reported to be the most abundant minerals occurring in pyrite-bearing schists. Phyllosilicate transformations were significantly stronger in dry conditions than in wet ones. This conclusion was supported by the fact that the inherited phyllosilicates predominated in the clay mineral fraction of waterlogged saprolites, whereas the secondary swelling minerals were minor components. In dry and extremely acidic saprolites (pH < 3), trioctahedral chlorite was dissolved and transformed into clay minerals (e.g. smectite and kaolinite), whereas swelling clays (smectite mainly) were formed at the expense of dioctahedral micas. The pH of water is an important factor influencing phyllosilicate transformations in waterlogged conditions. The phyllosilicate alterations under the influence of extremely acidic waters (pH < 3) were more advanced than in moderately acidic ones (pH of 4.6), as the secondary clay minerals seemed to be represented exclusively by smectite in the former, whereas HIMs and mixed-layer minerals such as R0 I-S-Ch, R0 I-S, as well as R1 Ch-V and/or R1 Ch-S occurred in the latter.
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