- Etudes de moeurs. 2e livre. Scènes de la vie de province. T. 2. Les célibataires : un ménage de garçon (French Edition);
- Comte de Monte-Cristo, Le (French Edition)?
- Manual Pinatubo und Mayon (German Edition)?
- Download PDF Pinatubo und Mayon (German Edition).
- perfect cone volcano - Mount Mayon!
- Posts navigation?
- Our email:!
Helens, because many data are available for these for example, Smith and Leeman, Compared to Mount St. These differences exist also if older Mount St. Helens dacites are considered, except for a few lavas of the Kalama period Smith and Leeman, Large-ion lithophile element LILE abundances in Pinatubo dacite are slightly higher in agreement with slightly higher K 2 O , zirconium Zr abundances are identical, and niobium Nb abundances are lower than in dacite from Mount St.
Sr and Nd isotopic compositions were measured on type 1 phenocryst-rich and type 2 phenocryst-poor dacites of Pinatubo.
Mount Pinatubo, Botolan: Hours, Address, Mount Pinatubo Reviews: 4.5/5
Both types give identical compositions within the error limits of the analytical method, even with some of the analyses carried out in different laboratories table 9. These compositions are in close agreement with the data reported by Castillo and Punongbayan this volume.
- Mount Pinatubo.
- Download PDF Pinatubo und Mayon (German Edition);
- mt pinatubo volcano: Topics by kahasogolony.tk?
- Blood Alley A Short Story.
- Backpacking Philippines Travel Guide (Updated for 12222)?
- Networked Graphics: Building Networked Games and Virtual Environments.
- Aggressive Männer und sanftmütige Frauen: Ein Konstrukt unserer Gesellschaft? (German Edition);
- In Any Event: Top Tips on Managing any Corporate Event?
- perfect cone volcano - Review of Mount Mayon, Luzon, Philippines - TripAdvisor?
A sample of the andesite found as an inclusion in a dacitic pumice clast Pin6, table 1 and similar to the andesite scoria described by Pallister and others had Sr and Nd isotopic compositions identical to those of the dacites table 9. In contrast, the basalt contains slightly more radiogenic Sr and slightly less radiogenic Nd than the dacites table 9. Table 9. Strontium, neodymium, and lead isotopic compositions of the Mount Pinatubo rocks and phenocrysts. Because of the small amounts of anhydrite present in the samples, this mineral was extracted by leaching with distilled water.
Since no other water-soluble mineral was observed in the dacite, and because the anhydrite is Sr rich SrO up to 0. In the four leachate samples analyzed, the anhydrite has the same Sr compositions as the whole rocks. This similarity supports the assumption of a primary magmatic origin for this sulfate, as suggested in the previous sections. Data obtained from other phenocrysts, plagioclase, and amphibole show likewise that they have crystallized in isotopic equilibrium with the silicate melt.
Figure 9. Inset shows all Pinatubo data in detail this paper; Castillo and Punongbayan, this volume. Main fields for data from the North Luzon, Bataan, and Mindoro segments are indicated. Data sources: North Luzon-Defant and others ; Bataan and Mindoro segments-Knittel and others , Defant and others , Mukasa and others ; Macolod corridor-Knittel and others , Knittel and others Knittel and others , Knittel and Defant and Defant and others , have shown that recent volcanism along the Luzon volcanic arc shows systematic regional variation. In northern Luzon North Luzon segment the volcanics have Sr-Nd isotopic compositions similar to older middle Tertiary plutonic rocks and to recent volcanics associated with westward subduction along the Philippine trench eastern coast of Luzon, fig.
Toward the south Bataan and Mindoro segments , the volcanics have progressively less radiogenic Nd and more radiogenic Sr values. Knittel and others and Defant and others suggested that these differences can be attributed to the incorporation of more crustal material into the source region of these mantle-derived magmas.
MAP: Active volcanoes in the Philippines
The likely source of the crustal material is subducted fragments from the North Palawan continental terrane NPCT , which collided with the Philippine archipelago during the late Miocene, or sediments derived from the NPCT fig. Therefore, it is unlikely that the sulfur enrichment observed in the Pinatubo magma is resulting from unusually large contamination by marine sediments evaporites. Lead isotopic compositions were measured on two crystal-rich dacites Pin4 and Pin7 , an andesite Pin6 and a basalt inclusion Pt They are listed in table 9 and are presented graphically in figure The dacite and the andesite have virtually the same composition, while the basalt contains slightly more radiogenic Pb.
Figure Lead isotopic compositions of Pinatubo eruption products this study; Castillo and Punongbayan, this volume compared to other eruption products from the Taiwan-Luzon arc. Data sources: Batan Island-Vidal and others , McDermott and other ; Taal volcano, precollision volcanics and postcollision rocks far from the collision zone-Mukasa and others , ; sediments-McDermott and others , Mukasa and others The observed steep trends indicate mixing between "precollision-type" mantle and subducted sediment.
Lead isotopic compositions obtained from various older rocks and rocks remote from the collision zone the West Philippines volcanic arc contain less radiogenic Pb Mukasa and others, Despite the relatively unradiogenic Sr and radiogenic Nd, the Pinatubo rocks fall well into the field of recent volcanic arcs postcollision located close to the NPTC collision zone.
Similar Pb isotopic ratios were also observed in lavas and mantle nodules from Batan Island, a volcanic island located north of Luzon fig. The presence of significant amounts of subducted sediment potentially can be monitored by 10 Be, a short-lived cosmogenic nuclide half-life 1. Thus, lack of detectable 10 Be does not imply the lack of a sediment component in the source region; 10 Be could also be undetected because the uppermost sediment layer was scraped off or because subducted components were recycled too slowly Woodhead and Fraser, Two samples of phenocryst-rich pumice, Pt12 and Pt25, which were also analyzed for their Sr and Nd isotopic composition table 9 , were chosen for 10 Be analysis.
These samples contain 1.
Mount Pinatubo - Wikipedia
These data are evidence that the Pinatubo dacites contain a sedimentary component that has been recycled through the subduction system. Table Beryllium isotopic compositions of whole-rock pumice. Individual anhydrite phenocrysts of June 12 products show a very broad range of 34 S values from 3 to 16, but phenocrysts of June 15 products show a narrower range of 34 S values McKibben and others, this volume. McKibben and others conclude that contamination of the magma by extraneous sulfur at shallow levels seems necessary to explain the observations on June 12 samples.
This conclusion is also made by Hattori this volume on the basis of a study of sulfides in the Pinatubo eruption products. Sulfur isotopic compositions of dacite, andesite, and ash samples from Mount Pinatubo. Two fresh ash samples collected on July 4, Pin12 and Pin14 , were analyzed also. The sulfur content of these ash samples table 1 is markedly higher than the sulfur content of the dacite because a significant amount of sulfate derived from the gas phase in the eruptive column is adsorbed on these samples.
In consequence, the measured 34 S is a mixed contribution of about 30 to 35 percent of sulfate from the gas phase and 65 to 70 percent of sulfate derived from the anhydrite microphenocrysts. These values are within the range of data obtained on the dacite. The basalt, found as inclusions in the June , , andesite lava, is likely to have been generated by partial melting of peridotite because of its high Mg content, the high Fo content of olivine phenocrysts, and the abundance of chromite inclusions in olivine.
This equilibrium between core compositions and the melt in turn implies that the basalt was not highly oxidized or was oxidized only at a late stage. This conclusion is supported by the presence of abundant sulfides in the basalt Hattori, this volume. The fact that the basalt appears to be in equilibrium with olivine Fo 88 would suggest that the magma is not far removed from its primary composition by fractional crystallization.
However, the relatively low nickel Ni content of the whole rock ppm Ni and the olivines 0. The position of the basalt in the plot suggests a value of about 14 kbar fig. In particular, the effect of olivine fractionation may have been increased by some assimilation, which is indicated by the presence of rare quartz, amphibole, and large plagioclase crystals in the basalt.
Subvertical lines are melts in equilibrium with olivine. The small square represents Pinatubo basalt with 10 percent olivine added see text. The arrows indicate the effect that fractionation and contamination have on compositions plotting in the same area as basalt of Mount Pinatubo. The composition of the basalt suggests earlier equilibration at about 14 kbar.
Pinatubo - definition of Pinatubo by The Free Dictionary
Primitive basalts are very rare in island arcs. The basalt inclusions of Mount Pinatubo closely resemble the primitive Macolod basalts in their major element composition, except for their lower Al 2 O 3 content fig. However, Taal basalts are distinctly more CaO rich compared to the Pinatubo basalt.
Major element compositions of basalts in weight percent from Pinatubo this paper; Pallister and others, this volume compared to other basalts from the Philippines Macolod basalts-Knittel and Oles, in press; basalts from Taal-Miklius and others, ; basalt from Malinao southern Luzon, Bicol arc-Knittel-Weber and Knittel, The scarcity of primitive basalts in arcs suggests that such magma may reach the surface in this environment only under special circumstances.
The Macolod corridor fig. The presence of primitive basalt in the Pinatubo eruption products suggests that this volcano also may be located in an extensional setting. Indeed, Mount Pinatubo is situated at the intersection of the volcanic front and the Iba fracture zone, a major east-southeast-trending structure that cuts the Zambales Ophiolite Complex fig.
Accordingly, we suggest that the magmatic activity of Mount Pinatubo is controlled by its position relative to the underlying plate and its location within what may be a tensional regime. The Iba fracture zone may be part of an incipient horst and graben system which, like the Macolod corridor, accommodates the differential movements resulting from eastward-directed subduction along the Manila trench to the north and westward-directed subduction along the Philippine trench to the south.
Additional evidence linking the basalt genesis to the setting of the Iba fracture zone is provided by the REE pattern of the basalt data in Pallister and others, this volume. Pallister written commun. Mount Arayat may owe its existence to some "weak" zone within the crust, though we note that it does not lie along strike of the Iba fracture zone.
There is no generally accepted model for the genesis of dacite at convergent plate boundaries, and possibly there is no single unique mechanism responsible for the generation of such rocks. Commonly, the following mechanisms for genesis of arc dacite are considered after Reid and Cole, The relatively high concentrations of incompatible trace elements in the basalt K, Rb, Ba, Zr; fig. For the same reason, Smith and Leeman concluded that the Mount St.
Helens dacite is not derived from basalts erupted from Mount St. In addition, the difference in isotopic composition between dacites and basalt rules out a cogenetic relation. Alternatively, there is evidence that some volcanoes produced different types of basalt for example, at Mount St. Helens; Leeman and others, and, thus, the dacites of Pinatubo could be derived from a basaltic precursor that is as yet not discovered at Mount Pinatubo.
However, REE data for the dacite provided by Pallister and others this volume and Castillo and Punongbayan this volume show that the dacite is depleted in HREE, and model calculations carried out by Martin show that such patterns probably cannot be generated by fractional crystallization of mantle-derived basalt. In view of the suggestion of Pallister and others that the eruption was triggered by the intrusion of basaltic magma into a reservoir containing evolved melt, could magma mixing be a process for the generation of the dacite?
According to Pallister and others , dacite was one of the endmembers, and mixing produced andesite. Therefore, if the Pinatubo dacite had been produced by mixing, this must have occurred prior to the events that led to the eruption.