Geochemical characteristics of boninite- and tholeiite-series volcanic rocks from the Mariana forearc and the role of an incompatible element–enriched fluid in arc petrogenesis

1987 ◽  
pp. 151-164 ◽  
Author(s):  
Sherman H. Bloomer
Keyword(s):  
Incompatible Element ◽  
Volcanic Rocks ◽  
Geochemical Characteristics ◽  
Tholeiite Series ◽  
Mariana Forearc

scholarly journals Petrological-geochemical characteristics of lavas, sources and evolution of magmatic melts of the Kazbek neovolcanic center (Greater Caucasus)

2019 ◽  
Vol 27 (6) ◽  
pp. 658-689
Author(s):  
A. V. Parfenov ◽  
V. A. Lebedev ◽  
I. V. Chernyshev ◽  
G. T. Vashakidze ◽  
A. I. Yakushev ◽  
...  
Keyword(s):  
Volcanic Rocks ◽  
Geochemical Characteristics ◽  
Crustal Assimilation ◽  
Magmatic System ◽  
Greater Caucasus ◽  
Leading Role ◽  
Mantle Reservoir ◽  
The Common ◽  
Geochemical Studies

The results of petrological-geochemical and isotope-geochemical studies of the Late Pleistocene-Holocene lavas of the Kazbek Neovolcanic Center, one of the largest centers of youngest magmatism in the Greater Caucasus, are presented. It has been established that the volcanic rocks of the Kazbek center arise a continuous compositional series basaltic (trachy-)andesites(trachy-)andesitesdacites with a predominance of calc-alkaline intermediate and moderately-acid lavas. The obtained results indicate that the processes of fractional crystallization and mixing of melts had a leading role in the petrogenesis of the rocks. The crustal assimilation was of limited importance; its influence is noticeable only in the rocks of the earliest and late pulses of magmatic activity within the Kazbek center. The common crustal lithologies participated in the assimilation were presented by metamorphosed Jurassic sediments (mainly shales and sandstones), forming the foot of the Kazbek center, and Mesozoic mafic metamorphosed volcanites very rarely. The specific features of AFC processes during the development of the studied magmatic system (including the presence of noticeable amount of water in the melt, the leading role of Amp in the cumulus and the absence of Pl fractionation) led to the appearance of dacitic lavas with geochemical signs of adakites as an evolutional end-member. The volcanic rocks of the Kazbek center are derived from trachybasalt magmas, the source of which was presented by the mantle reservoir of OIB-type. Recent and previously published results of studies of the Neogene-Quaternary magmatism manifested within the Greater Caucasus show that the main petrological and geochemical characteristics of this regional mantle reservoir remained constant from the end of the Miocene to the present time.

scholarly journals Pleistocene Volcanic Rocks in the Mariana Forearc Revealed by Drilling at Site 781

1992 ◽  
Author(s):  
M.S. Marlow ◽  
L.E. Johnson ◽  
J.A. Pearce ◽  
P.B. Fryer ◽  
L.G. Pickthorn ◽  
...  
Keyword(s):  
Volcanic Rocks ◽  
Mariana Forearc

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.  

Identifying Early Carboniferous bimodal volcanic rocks and geochemical characteristics in the Atengtao Mountain, Yili Block (Chinese western Tianshan)

2018 ◽  
Vol 53 ◽  
pp. 148-162 ◽  
Author(s):  
Zuopeng Wang ◽  
Yongjun Li ◽  
Lili Tong ◽  
Gaoxue Yang ◽  
Pengfei Ren ◽  
...  
Keyword(s):  
Volcanic Rocks ◽  
Early Carboniferous ◽  
Geochemical Characteristics ◽  
Western Tianshan

scholarly journals Geochemical Characteristics of Volcanic Rocks from Mt. Masurai’s Caldera, Jambi, Indonesia

2019 ◽  
Vol 1204 ◽  
pp. 012070 ◽  
Author(s):  
Asep Rohiman ◽  
Dipowiguno Prijanto ◽  
Arief Prabowo ◽  
Antonius Ratdomopurbo ◽  
Ruly Setiawan ◽  
...  
Keyword(s):  
Volcanic Rocks ◽  
Geochemical Characteristics

Geochemistry of ultrapotassic volcanic rocks in Xiaogulihe NE China: Implications for the role of ancient subducted sediments

Lithos ◽  
2014 ◽  
Vol 208-209 ◽  
pp. 53-66 ◽  
Author(s):  
Yang Sun ◽  
Jifeng Ying ◽  
Xinhua Zhou ◽  
Ji'an Shao ◽  
Zhuyin Chu ◽  
...  
Keyword(s):  
Volcanic Rocks ◽  
Ne China
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