scholarly journals Biosignatures in Subsurface Filamentous Fabrics (SFF) from the Deccan Volcanic Province, India

Minerals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 540 ◽  
Author(s):  
Jens Götze ◽  
Beda Hofmann ◽  
Tomasz Machałowski ◽  
Mikhail V. Tsurkan ◽  
Teofil Jesionowski ◽  
...  
Keyword(s):  
Cross Sections ◽  
Mineralogical Composition ◽  
Deccan Volcanic Province ◽  
Volcanic Province ◽  
Fibrous Minerals ◽  
Initial Nucleus ◽  
Sheet Silicates ◽  
Mineralization Processes ◽  
Maximum Temperatures ◽  
Host Rocks

The morphology, chemical, and mineralogical composition of subsurface filamentous fabrics (SFF) from the Deccan Volcanic Province (DVP) were investigated to determine the origin of these spectacular aggregates. SFF occur in a wide variety of morphologies ranging from pseudo-stalactites to irregular fabrics and are classified as SFFIr (irregular) or SFFMa (matted). The SFF samples exhibit a thread-like (or filament-like) center from which mineral precipitation starts to form the final macroscopic morphologies. Detailed investigations revealed organic material (fungal chitin) in the innermost filamentous core, which may have acted as an initial nucleus for the mineralization processes. The morphometric characteristics of certain filamentous fabrics are very similar to those of microbial filaments and the fabrics formed from them but are clearly distinct from similar types of non-biological precipitates (fibrous minerals, speleothems, and “chemical gardens”). These features indicate that the filamentous cores might be products of microbial communities that were active in the basaltic cavities. The SFF cross-sections display similar concentric layers of the mineral succession and reach thicknesses of several centimeters with spectacular lengths up to 100 cm and constant diameters. The typical mineralization sequence points to temporal variation in the chemical composition of the mineralizing fluids from Fe(Mg)-rich (Fe-oxides/-hydroxides, Fe-rich sheet silicates such as celadonite and di-/tri-smectite) to Ca-dominated (Ca-rich zeolites) and finally pure SiO2 (opal-CT, chalcedony, and macro-crystalline quartz). Assuming biological activity at least during the early mineralization processes, circumneutral pH conditions and maximum temperatures of 100–120 °C were supposed. The formation of filamentous cores including Fe-bearing phyllosilicates probably occurred near the surface after cooling of the lava, where the elements necessary for mineral formation (i.e., Si, Mg, Al, Fe) were released during alteration of the volcanic host rocks by percolating fluids.

Fluoride Accumulation in Groundwater from Semi-arid Part of Deccan Volcanic Province, India: A Cause of Urolithiasis Outbreak

2017 ◽  
Vol 1 (1) ◽  
pp. 9-17 ◽  
Author(s):  
Sanjay Kale ◽  
N. J. Pawar
Keyword(s):  
Medical Records ◽  
Fluoride Concentration ◽  
Data Generation ◽  
Deccan Volcanic Province ◽  
Temporal And Spatial Distribution ◽  
Volcanic Province ◽  
Fluoride Accumulation ◽  
Hot Days ◽  
Geochemical Investigation ◽  
Relationship Of

Groundwater fluoride and health problem was meticulously studied for dental and skeleton fluorosis except few studies on urolithiasis. Urolithiasis is multi-factorial disease and excess fluoride consumption is one of the causal factors. In view of this, increase of fluoride in groundwater is reported in semiarid Deccan Volcanic Province (DVP), India. To understand the fluoride and urolithiasis association, present study was carried out in Karha river basin of DVP region. Three stages of data generation were adopted for present study such as procuring of medical records of urolithiasis, previous groundwater chemistry data and geochemical investigation of 50 groundwater samples from representative villages. Further, these variables were used for correlation analysis, temporal and spatial distribution to find out their relationships. Result shows medical records of hospitals indicating the gradual increase in urolithiasis is reported during drought situations. In temporal variation, annual fluoride concentration of groundwater and hot days are positively correlated with annual urolith patients as well as spatial study supports the same. In conclusion, present study highlights the relationship of urolith formation with number of hot days, groundwater electrical conductivity and fluoride. However, detailed biomedical study may lead towards understanding of fluoride- urolithiasis relationship.

Shale gas leakage in lower Ecca shales during contact metamorphism by dolerite sill intrusions in the Karoo Basin, South Africa

2021 ◽  
Author(s):  
V. Nengovhela ◽  
B. Linol ◽  
L. Bezuidenhout ◽  
T. Dhansay ◽  
T Muedi ◽  
...  
Keyword(s):  
South Africa ◽  
Grain Boundaries ◽  
Shale Gas ◽  
Elevated Temperatures ◽  
Contact Metamorphism ◽  
Microscopy Imaging ◽  
Gas Leakage ◽  
Karoo Basin ◽  
Maximum Temperatures ◽  
Host Rocks

Abstract Contact metamorphism along widespread dolerite sills and dykes, emplaced at 182 to 183 Ma through the sedimentary host rocks of the Karoo Basin, triggered devolatilization of carbon-rich shales of the Lower Ecca Group. Hornfel samples collected from drill cores that intersect dolerite sills were analyzed for mineral phase equilibria, chemistry and porosity to characterize thermal aureoles at various distances from sill intrusions. Andalusite-chiastolite and cordierite porphyroblasts with biotite and muscovite occur within 10 to 20 m of many intrusive contacts. These metamorphic minerals crystallized when host shales attained maximum temperatures ranging between 450 and 600°C. Scanning electron microscopy imaging confirms that the hornfels are compact and that their metamorphic minerals limit porosity along grain boundaries. In few cases intra-mineral porosity occurs within individual crystals such as calcite, andalusite and cordierite. Disequilibrium metamorphic textures such as irregular grain boundaries, and inclusions in andalusite and cordierite reveal that the elevated temperatures were too short-lived to accomplish complete (re)crystallization. Thermal modeling results are consistent with the observed metamorphic mineral assemblages. Gas leakage calculations along a 7 m and a 47 m thick dolerite sill that intrude toward the top of the Whitehill Formation suggest that methane volumes ranging between 8 to 15 Tcf were generated during the sill emplacement. Methane was likely released into the atmosphere through hydrothermal vent complexes that are well preserved in the western Karoo Basin. If such loss was widespread across the entire basin, the implications for paleo-climate change and preserved shale gas reserves in the Karoo Basin of South Africa would be significant.

scholarly journals The Mineralogical Composition of Samos Zeoliitic Rocks and their potential use as Feed Additives and Nutrition Supplements

2020 ◽  
Vol 56 (1) ◽  
pp. 84
Author(s):  
Anestis Filippidis ◽  
Christina Mytiglaki ◽  
Nikolaos Kantiranis ◽  
Ananias Tsirambides
Keyword(s):  
Clay Minerals ◽  
Animal Species ◽  
Mineralogical Composition ◽  
Feed Additives ◽  
Feed Additive ◽  
X Ray Diffraction ◽  
Eu Regulation ◽  
Fibrous Minerals ◽  
Potential Use ◽  
The Eu

Fifteen (15) zeolitic rocks from Karlovassi-Marathokampos basin of Samos Island (Greece) were investigated for their mineralogical composition by X-Ray Diffraction (XRD) method. According to EU Regulation No 651/2013, clinoptilolite of sedimentary origin with ≥80 wt% clinoptilolite, ≤20 wt% clay minerals, free of fibres and quartz, can be used as feed additive for all animal species. Depending on the zeolites, the zeolitic rocks are grouped to those containing: Clinoptilolite (33-86 wt%), clinoptilolite (59 wt%) + mordenite (20-21 wt%), clinoptilolite (22 wt%) + analcime (29 wt%), clinoptilolite (17 wt%) + phillipsite (27 wt%), analcime (29-70 wt%), mordenite (62%) and chabazite (63 wt%). None of the clinoptilolite-containing rocks (10 samples) meet the requirements of the EU Regulation No 651/2013, and thus cannot be used as feed additives for all animal species and consequently as nutrition supplements, since all of them contain 2-5 wt% quartz, two of them 20-21 wt% mordenite (fibrous zeolite), nine of them <80 wt% clinoptilolite (17-73 wt%) and two of them >20 wt% clay minerals (27-42 wt%). Although the EU Regulation No 651/2013 refers to clinoptilolite of sedimentary origin, using the presence or absence of quartz and fibrous minerals, none of the five mordenite, analcime and chabazite containing zeolitic rocks, can be used as feed additives and nutrition supplements, since all of them contain 2-6 wt% quartz and one of them contains 62 wt% mordenite (fibrous zeolite).

Mapping the sub-trappean Mesozoic sediments in the western part of Narmada–Tapti region of Deccan Volcanic Province, India

2014 ◽  
Vol 93 ◽  
pp. 15-24 ◽  
Author(s):  
A.S.N. Murty ◽  
Dipankar Sarkar ◽  
Mrinal K. Sen ◽  
V. Sridher ◽  
A.S.S.S.R.S. Prasad
Keyword(s):  
Deccan Volcanic Province ◽  
Volcanic Province

scholarly journals Visualizing mineralization processes and fossil anatomy using synchronous synchrotron X-ray fluorescence and X-ray diffraction mapping

2020 ◽  
Vol 17 (169) ◽  
pp. 20200216 ◽  
Author(s):  
Pierre Gueriau ◽  
Solenn Réguer ◽  
Nicolas Leclercq ◽  
Camila Cupello ◽  
Paulo M. Brito ◽  
...  
Keyword(s):  
Cross Sections ◽  
Soft Tissues ◽  
Local Strain ◽  
Phase Identification ◽  
X Ray Diffraction ◽  
X Ray ◽  
Area Detector ◽  
Transmission Geometry ◽  
Mineralization Processes ◽  
Elemental Data

Fossils, including those that occasionally preserve decay-prone soft tissues, are mostly made of minerals. Accessing their chemical composition provides unique insight into their past biology and/or the mechanisms by which they preserve, leading to a series of developments in chemical and elemental imaging. However, the mineral composition of fossils, particularly where soft tissues are preserved, is often only inferred indirectly from elemental data, while X-ray diffraction that specifically provides phase identification received little attention. Here, we show the use of synchrotron radiation to generate not only X-ray fluorescence elemental maps of a fossil, but also mineralogical maps in transmission geometry using a two-dimensional area detector placed behind the fossil. This innovative approach was applied to millimetre-thick cross-sections prepared through three-dimensionally preserved fossils, as well as to compressed fossils. It identifies and maps mineral phases and their distribution at the microscale over centimetre-sized areas, benefitting from the elemental information collected synchronously, and further informs on texture (preferential orientation), crystallite size and local strain. Probing such crystallographic information is instrumental in defining mineralization sequences, reconstructing the fossilization environment and constraining preservation biases. Similarly, this approach could potentially provide new knowledge on other (bio)mineralization processes in environmental sciences. We also illustrate that mineralogical contrasts between fossil tissues and/or the encasing sedimentary matrix can be used to visualize hidden anatomies in fossils.

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