نتایج جستجو برای: volcanic breccia

تعداد نتایج: 15341  

2005
D. J. MILTON F. A. MACDONALD

Goat Paddock in northern Western Australia is a *5 km-diameter impact crater of Eocene age excavated in gently dipping Proterozoic sandstones. Roughly radial gorges formed by post-impact erosion provide cross-sectional views of the wall and rim zone. The predominant structural theme is one of synclinal rim folding with broad zones in which bedrock strata were deformed by impact to steep, vertic...

Journal: :Journal of South American Earth Sciences 2021

Several processes have been proposed as triggering mechanisms for the large sector collapses that affect most volcanoes, and which may occur several times in volcano's lifetime. Here we present discuss case of Tutupaca volcano, located southern Peru part Central Volcanic Zone Andes. is composed an old, hydrothermally altered highly eroded Basal edifice, well younger twin peaks northern complex ...

2002
Ryoichi Mizuno Yoshinori Dobashi Tomoyuki Nishita

The animation of volcanic smoke is useful for natural disaster simulations, entertainments, etc. In this paper, we propose a model to generate realistic animations of the volcanic smoke. The model is designed by taking the eruption magnitude decided by the eruption velocity and the initial volcanic smoke density, the buoyancy generated by the difference between the volcanic smoke density and th...

Journal: :Journal of human evolution 2016
Luis Gibert Gary R Scott Denis Scholz Alexander Budsky Carles Ferràndez Francesc Ribot Robert A Martin María Lería

Cueva Victoria has provided remains of more than 90 species of fossil vertebrates, including a hominin phalanx, and the only specimens of the African cercopithecid Theropithecus oswaldi in Europe. To constrain the age of the vertebrate remains we used paleomagnetism, vertebrate biostratigraphy and (230)Th/U dating. Normal polarity was identified in the non-fossiliferous lowest and highest strat...

2003
Noah E. Petro Carlé M. Pieters

Introduction: The South Pole-Aitken (SPA) Basin is the largest, oldest basin on the Moon. The extreme size of the basin, ≤2,500 km in diameter and a present depth of up to 13km [1,2], suggests that much of the upper crust would have been excavated during the formation/impact event, exposing the lower crust or upper mantle. Also, a large volume of impact melt breccia containing extensive lower c...

2011
V. Pinel

Volcanic edifice construction at the Earth's surface significantly 3 modifies the stress field within the underlying crust with two main implica

2015
Cristina Riquelme Jennifer J. Marshall Hathaway Maria de L. N. Enes Dapkevicius Ana Z. Miller Ara Kooser Diana E. Northup Valme Jurado Octavio Fernandez Cesareo Saiz-Jimenez Naowarat Cheeptham

Volcanic caves are filled with colorful microbial mats on the walls and ceilings. These volcanic caves are found worldwide, and studies are finding vast bacteria diversity within these caves. One group of bacteria that can be abundant in volcanic caves, as well as other caves, is Actinobacteria. As Actinobacteria are valued for their ability to produce a variety of secondary metabolites, rare a...

حیدریان شهری, محمدرضا, قادری, مجید, کریم‌پور, محمدحسن, سمیعی, سمیه ,

Khunik area is located in eastern Iran, about 106 km south of Birjand. Preliminary prospecting in the area, using ASTER mineral mapping (SAM) for locating possible alteration zone in the area provided satisfactory results when checked with field observation. The area comprises outcrops of Paleocene to Eocene volcanics, which was intruded telescopically by several subvolcanic intermediate bodies...

2016
Harri Geiger Abigail K. Barker Valentin R. Troll

Mt. Cameroon is one of the most active volcanoes in Africa and poses a possible threat to about half a million people in the area, yet knowledge of the volcano's underlying magma supply system is sparse. To characterize Mt. Cameroon's magma plumbing system, we employed mineral-melt equilibrium thermobarometry on the products of the volcano's two most recent eruptions of 1999 and 2000. Our resul...

2011
I. L. Karol

Classes of atmospheric aerosols and their main sources, distributions of tropospheric aerosol by size and mass, their physico-chemical composition and principal optical properties in various spectral bands are described. Stratospheric aerosols in “quiet” and “disturbed” periods after the major volcanic eruptions, their interactions with clouds and of underlying surface radiative properties affe...

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