scholarly journals A preliminary study of acid volcanic rocks for stonemeal application

2014 ◽  
Vol 1-2 ◽  
pp. 30-35 ◽  
Author(s):  
Claudete Gindri Ramos ◽  
Andréia Gislaine de Mello ◽  
Rubens Müller Kautzmann
Keyword(s):  
Volcanic Rocks ◽  
Acid Volcanic ◽  
Preliminary Study

scholarly journals Peran Kontaminasi Kerak pada Diferensiasi Magma Pembentuk Batuan Vulkanik Sungai Ampalas, Mamuju, Sulawesi Barat

EKSPLORIUM ◽  
2020 ◽  
Vol 41 (2) ◽  
pp. 73
Author(s):  
Windi Anarta Draniswari ◽  
Sekar Indah Tri Kusuma ◽  
Tyto Baskara Adimedha ◽  
I Gde Sukadana
Keyword(s):  
Magma Mixing ◽  
Volcanic Rocks ◽  
Geochemical Characteristics ◽  
X Ray ◽  
Radioactive Mineral ◽  
Alkaline Feldspar ◽  
High Alkalinity ◽  
Preliminary Study ◽  
Xrf Analyses

ABSTRAK Anomali radiometri telah ditemukan di area Sungai Amplas pada bongkah batuan vulkanik. Nilai yang terukur dari spektrometer gama adalah 787 ppm eU dan 223 ppm eTh. Penemuan ini menarik untuk pengembangan eksplorasi. Studi lebih lanjut diperlukan untuk mengetahui karekteristik batuan pembawa mineral radioaktif dari sampel in-situ. Penelitian ini bertujuan untuk mengetahui karakteristik petrologi dan geokimia batuan vulkanik Ampalas sebagai studi awal untuk mengetahui proses akumulasi mineral radioaktif pada batuan vulkanik Ampalas. Metodologi yang digunakan meliputi pengamatan lapangan, pengambilan sampel batuan, analisis petrografi dan X-Ray Fluorescence (XRF). Batuan vulkanik ampalas tersusun atas ponolit, foidit, dan foid-syenit. Tekstur batuannya terdiri dari porfiritik, aliran, rim piroksen, zoning, pseudo-leusit, korosi, inklusi mafik, dan sieve. Karakteristik geokimia menunjukkan alkalinitas tinggi dan indikasi pengayaan mineral radioaktif yang tersebar dalam batuan. Proses magmatis yang berperan dalam pembentukan batuan vulkanik adalah fraksionasi kristal (fraksionasi leusit dan alkali felspar), asimilasi kerak kontinen, dan pencampuran magma. Interaksi antara magma dan kerak menyebabkan diferensiasi magma berkelanjutan yang menghasilkan akumulasi uranium dan torium lebih tinggi.ABSTRACT Anomalous radiometry has been found in Ampalas River Area on volcanic rock boulder. The values measured from gamma spectrometer are 787 ppm eU and 223 ppm eTh. This discovery is promising for exploration development. Further study need to figure the radioactive mineral bearing rock characteristic from in-situ samples. The research aim is to determine the petrology and geochemical characteristics of Ampalas volcanic rocks as preliminary study to find radioactive mineral accumulation process of Ampalas volcanic rocks. The methodologies are field observation, rock sampling, petrography, and X-Ray fluorescence (XRF) analyses. The Ampalas volcanic rocks consist of phonolite, phoidite, and phoid syenite. Their textures are porphyritic, flow, pyroxene rim, zoning, pseudo-leucite, corrosion, mafic inclusions, and sieve. The geochemical characteristics show high alkalinity and radioactive mineral enrichment disseminating on rock. The magmatic processes which play a significant role in radioactive mineral-bearing rocks formation are crystal fractionations (leucite and alkaline feldspar fractionations), continental crust assimilation, and magma mixing. Long interaction between magma and crust creates advanced magma differentiation causing higher uranium and thorium accumulation.  

Rare earth elements in volcanic rocks associated with Cu–Zn massive sulphide mineralization: a preliminary report

1982 ◽  
Vol 19 (3) ◽  
pp. 619-623 ◽  
Author(s):  
I. H. Campbell ◽  
P. Coad ◽  
J. M. Franklin ◽  
M. P. Gorton ◽  
S. D. Scott ◽  
...  
Keyword(s):  
Volcanic Rocks ◽  
Massive Sulphide ◽  
Genetic History ◽  
Felsic Volcanism ◽  
Preliminary Study ◽  
Selection For ◽  
Felsic Volcanic ◽  
High Degree ◽  
Ree Patterns ◽  
Felsic Volcanic Rocks

Massive sulphide deposits are closely associated with felsic volcanism. This association is believed to be genetic and it forms the cornerstone for most exploration programs, but unfortunately not all felsic volcanic rocks contain ore. It seems likely that ore-bearing felsic volcanic rocks have a different genetic history from those that are barren and, if this is so, these differences should be reflected in their REE geochemistry.A preliminary study of REE in Archean felsic volcanic rocks has shown that those associated with ore have flat REE patterns with well-developed Eu anomalies whereas those from barren volcanic rocks have steep REE patterns with weak or absent Eu anomalies. The felsic volcanic rocks associated with ore can be subdivided into two types: tholeiitic and calc-alkaline. Kam-Kotia, Matagami, and South Bay are tholeiitic whereas Sturgeon Lake, Golden Grove, and Kuroko are calc-alkaline.The well-developed Eu anomalies in the ore-related felsic volcanic rocks indicate that the melt has undergone a high degree of fractional crystallization en route to the surface, suggesting the existence of a subvolcanic magma chamber below the orebody. The characteristic REE patterns of the ore-associated felsic volcanics should help mining companies in area selection for massive sulphide exploration.

scholarly journals III.—On the Probable Pelean Origin of the Felsitic Slates of Snowdon, and their Metamorphism

1905 ◽  
Vol 2 (12) ◽  
pp. 541-549 ◽  
Author(s):  
J. R. Dakyns ◽  
Edward Greenly ◽  
J. R. Dakyns
Keyword(s):  
Viscous Flow ◽  
Volcanic Rocks ◽  
Acid Volcanic

There are several kinds of acid volcanic rocks in Wales. In the X neighbourhood of Snowdon there are at least five kinds, as follows:1. There are undoubted lavas, showing lines of viscous flow and sometimes vesicular, and weathering into cubical blocks. Such may be seen on Crib Goch and on Crib Yddysgl, on Cerrig Cochion, and elsewhere. These rocks are rarely cleaved.2. There are rocks like the last as to fracture and mode of weathering, but which are neither viscous nor vesicular. They are probably masses of felsitic dust or mud. Such may be seen in Cwm Llan.3. There are also massive felstones, rudely cleaved, such as form Moel Meirch. and Clogwyn Llwyd.4. There are the so-called ashes of various kinds, usually wellbedded and often highly cleaved.5. Lastly, there are highly cleaved felsitic rocks, which show no lines of viscous flow, are generally unbedded, and which are in many places fragmentary.

Possible signs of liquation in acid volcanic rocks

1980 ◽  
Vol 22 (12) ◽  
pp. 1437-1442
Author(s):  
N. V. Koronovskiy ◽  
E. D. Fromberg
Keyword(s):  
Volcanic Rocks ◽  
Acid Volcanic
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