The paper describes the secondary alteration and petrophysical properties of the host rocks in Yagodninskoe zeolite deposit (Kamchatka Peninsula). The deposit has hydrothermal origin where vitric tuffs and perlites have been transformed to zeolitebearing rocks. Intensity of zeolitization varies from moderate to almost totally altered rocks where glassy matrix is totally recrystallized to fine-grained zeolitic aggregate. Clinoptilolite and mordenite are the most abundant among zeolites; smectites and silica minerals are also presented in secondary mineral assemblage. The relationship between petrophysical properties of the rocks and petrographic features such as composition, structure and secondary alteration were studied. The special attention is given to intensity of hydrothermal alterations and their influence on the rock properties. 1. INTRODUCTION The study of natural zeolites and their deposits are of great interest in science and technology and remain relevant nowadays due to the special properties of these minerals and their wide usage in various sectors of the industry. Yagodninskoe deposit is a large deposit of natural zeolite, which has been prospected in Kamchatka Peninsula. It attracts many researchers due to the propagation of contrasted rock compositions, wide occurrence of ignimbrites and rhyolite tuffs, formation of large calderas, and dome-ring structures. A detailed study of the deposit area is important for better understanding of the evolution of magmatism, volcanic and hydrothermal activity in the area of Banno-Karymshinkii district. The main target of the presented research is to study alteration of volcanic rocks, to identify types and morphology of zeolites, to determine petrophysical properties of the host rocks and to assess the effect of hydrothermal alteration on rock properties. The samples were collected in 2011-2012 by the staff of Institute of Volcanology and Seismology during the field work. Forty samples of various alteration degree were selected from outcrops for laboratory studies.
PLEASE NOTE: There was an issue with some of the total porosity data in a previous version of the database (the decimal place was shifted). Please use this version of the database. Please contact samuelwarrenscott--at--gmail.com if there are any questions. The Valgarður database is a compilation of data describing the physical and geochemical properties of Icelandic rocks. The dataset comprises 1072 samples obtained from fossil and active geothermal systems, as well as relatively fresh volcanic rocks erupted in sub-aerial or sub-aqueous environments. The database includes petrophysical properties (effective and total porosity, grain density, permeability, electrical resistivity, acoustic velocities), as well as mineralogical and geochemical data obtained by point-counting, X-ray Fluorescence (XRF), quantitative X-ray Diffraction (XRD), and Cation Exchange Capacity (CEC) analyses. The motivation behind this database is threefold: (i) aid in the interpretation of geophysical data including uncertainty estimations, (ii) facilitate the parameterization of numerical reservoir models, and (iii) improve our understanding of the relationship between rock type, hydrothermal alteration and petrophysical properties.
Island-arc calc-alcaline dacites (66,7% of SiO 2 , 3,4% of Na 2 O, 1,9% of K 2 O) compose a subvolcanic body among tuffs, andesites and trachyandesites in the east of the Kara-Dag volcanic massif of the Rocky Crimea. The unique features of dacites is abundance of plagioclase phenocrysts (the central zone is bytownite Ca 75–72 Na 24–27 K 0,5–1 ; the intermediate and external zones is labradorite Ca 67–52 Na 32–47 K 1 ) and low-Ti augite (augite Ca 43–41 Mg 41–38 Fe 16–21 with 1–2% of Al 2 O 3 composes the core; the intermediate and external zones is augite Ca 43–41 Mg 41–38 Fe 16–21 with 1–2% Al 2 O 3 ). Titanomagnetite, ilmenite and apatite form intergrowths with augite. Lowmagnesian titanomagnetite is enriched with manganese (up to 4,5 wt.% MnO) and zinc (up to 1,6% of ZnO); it contains from 39 to 28% of ulvospinel minal. Ilmenite, poor in Mn, contains from 10 to 25 mol.% of hematite minal that demonstrates the crystallization with the raised f O 2 , in other words, the water saturation of fusion. Apatite is poor in Sr, Ce and S. The trend with standard accumulation of fluorine from chlorine-hydroxyl-fluorapatite up to fluorapatite is shown. Plagioclase microlites — labradorite Ca 52–50 Na 46–48 K 2–3 composes the cementing mass of rhyolitic composition (77,3% SiO 2 , 3,3% Na 2 O, 2,5% K 2 O) with quartz, small amounts of andesine Ca 49–46 Na 49–52 K 2–3 , oligoclase Ca 27 Na 68 K 5 and anorthoclase in interstitions. The speciality of the described dacites is plagioclase wealth in anorthite component, what is typical for island-arc volcanites. The crystallization temperature of augite is ~1050–950 ᵒC. The crystallization temperature of associated titanomagnetite and ilmenite of early origin is ~900 ᵒC, f O 2 exceed by 1 logarithmic unit the QFM buffer, their late origin crystallization temperature is ~880 ᵒC, f O 2 exceed by 2 logarithmic units the QFM buffer.
For the first time, the results of petrophysical studies of the Bezymianny volcano extrusive rocks from dacites to andesites are presented. A comparative characteristic of the extrusive rocks properties is given according to the selected age groups. The dynamics of changes in the properties of extrusion rocks depending on their age is shown: it is established that the older the rocks, the higher the indicators of their density, strength and elastic properties. The petrophysical features of the rocks of the extrusive domes and lava flows are compared. The applicability of petrophysical properties to clarify the genesis of rocks similar in petrographic characte-ristics, in particular, of extrusive and effusive origin, is substantiated.
The Valgarður database is a compilation of data describing the physical and geochemical properties of Icelandic rocks. The dataset comprises 1072 samples obtained from fossil and active geothermal systems, as well as relatively fresh volcanic rocks erupted in sub-aerial or sub-aqueous environments. The database includes petrophysical properties (effective and total porosity, grain density, permeability, electrical resistivity, acoustic velocities), as well as mineralogical and geochemical data obtained by point-counting, X-ray Fluorescence (XRF), quantitative X-ray Diffraction (XRD), and Cation Exchange Capacity (CEC) analyses. The motivation behind this database is threefold: (i) aid in the interpretation of geophysical data including uncertainty estimations, (ii) facilitate the parameterization of numerical reservoir models, and (iii) improve our understanding of the relationship between rock type, hydrothermal alteration and petrophysical properties.
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