999 research outputs found
Letter from unknown writer to Jesse L. Boyce
No full textLetter to Jesse L. Boyce from unknown author (possibly Jack) about the investigation into the powder magazine located in the Grand Canyon. Some personal news is included in the letter such as the writer's marriage to the daughter of C.A. Taylor, former Supervisor of Cochise County
Letter from Jes Boyce to Jack
No full textLetter from Jesse L. Boyce to Jack regarding the storage of dynamite in Shoski Canyon
Letter from Jesse L. Boyce to Jack
No full textLetter from Jesse L. Boyce to Jack in which he refers to W. W. Crosby as a "damn carpetbagger" and his frustration at Crosby making him out to be a "liar"
Letter from Jesse L. Boyce to Carl Hayden
No full textLetter from Jesse L. Boyce to Carl Hayden stating that the Director of the National Park Service will order Colonel Crosby to remove the dynamite from the park
Letter from Jesse L. Boyce to Carl Hayden
No full textLetter from Jesse L. Boyce to Carl Hayden stating there is 30 tons of dynamite located in the Grand Canyon near tourist sites
Letter from unknown writer to Jesse L. Boyce
No full textLetter from unknown author (possibly Jack) to Jesse L. Boyce regarding his complaint concerning the TNT located in the Grand Canyon. Enclosed is Superintendent Crosby's report in which he states that the current housing location of the TNT is not a threat to anyone
Stable isotope (δ18O, δD) composition of magmatic fluids exsolved from an active alkaline magma chamber—the case of the AD 79 magma chamber of Vesuvius
No full textThis work documents, for the first time, the calculated oxygen and hydrogen isotope composition of the brines exsolved from the peripheral margin of the active magma alkaline chamber that fed the AD 79 (“Pompei”) eruption of Vesuvius. The exsolved hydrosaline fluids had a constant δ18O composition and a variable δD composition, showing a general lowering of δD at nearly constant δ18O content. We argue that the progressive fluid exsolution at the upper peripheral parts of the AD 79 magma chamber may explain this isotopic path. The modeling of the evolution of the hydrogen isotope composition of water remaining dissolved in the melt, and of the exsolved fluid as a consequence of progressive degassing, would favor multiple fluid-release events from the magmatic reservoir. A schematic model on the pulsed accumulation and release of fluids at the top of the magmatic reservoir prior to the eruption is thus proposed. The assessment of the stable isotope composition of the fluids exsolved from the AD 79 magma chamber of Vesuvius may be particularly relevant for the geochemical surveillance of the volcano as it may help to interpret the isotopic composition of fumarolic gases and its variations
Letter from Stephen T. Mather, U.S. National Park Service to Jesse L. Boyce
No full textLetter from the Director of the National Park Service, Stephen T. Mather, to Jesse L. Boyce informing him that immediate action is being taken to remove the TNT from the Grand Canyon
Fluids in early stage hydrothermal alteration of high-sulfidation epithermal systems: A view from the Vulcano active hydrothermal system (Aeolian Island, Italy)
No full textHigh-sulfidation (HS) epithermal systems have elements in common with passively degassing volcanoes associated with high T,
acid fumarole fields or acid crater lakes. They are considered to form in two stages, the first of which involves advanced argillic
alteration resulting from intense, strongly acidic fluid–rock interaction. The La Fossa hydrothermal system (Vulcano Island)
represents a classic example of such an active HS system and can be considered as a modern analogue of this early stage of
alteration, resulting in a core of intense silicic (90–95% pure SiO2) alteration surrounded by alunitic alteration zones.
This paper focuses on a geochemical and stable isotope study of the surficial alteration facies of Vulcano – particularly the horizon
characterized by strong silicic alteration – and on deep seated xenoliths ejected during the last eruption of La Fossa volcano (1888–90)
that can be considered as representative of fragments of the deep conduit system of La Fossa volcano. Using directly measured
temperatures at the sites of sampling, we have calculated fluid composition in isotopic equilibrium with the alteration products. The
large range of measured silica δ18O (12.3 to 29‰) reflects the wide range of formation temperatures (80–240 °C). The fluid
compositions calculated for intense silicic alteration vary from −0.9 to +6.5‰. These are significantly heavier than local meteoric
water (−6‰), and are consistent with derivation from the condensation of high-temperature fumarolic gases, dominated by magmatic
fluids and rich in acid gases (SO2, H2S, HCl, HF), into shallow groundwaters of meteoric origin, with dynamically variable ratios of
fumarolic steam/meteoric water. The calculated δ18O and δD of water in equilibrium with alunite also suggest the mixing of magmatic
and meteoric waters for the fluids involved in the genesis of advanced argillic alteration facies.
The calculated δ18Oofwater in equilibrium with hedenbergitic clinopyroxene, found in a veinlet in ametasomatized xenolith is +8.9‰.
This value cannot reasonably result from water–rock interaction between the host volcanic rocks and surface water. Instead, it most likely
represents a fluid (brine) exsolved from magma, which was responsible for high temperature metasomatism in the deep conduit system.
© 2007 Elsevier B.V. All rights reserved
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