scholarly journals Evolution of the volcanic plumbing systemof Alicudi (Aeolian Islands - Italy): evidence from fluid and melt inclusionsin quartz xenoliths

2009 ◽  
Vol 47 (4) ◽  
Author(s):  
R. Bonelli ◽  
M. L. Frezzotti ◽  
V. Zanon ◽  
A. Peccerillo
Keyword(s):  
Partial Melting ◽  
Fluid Inclusions ◽  
Type I ◽  
Type Ii ◽  
Early Type ◽  
Late Type ◽  
Crustal Rocks ◽  
Melt And Fluid Inclusions ◽  
Two Generations ◽  
Lower Crustal

Quartz-rich xenoliths in lavas (basalts to andesites; 90-30 ka) from Alicudi contain abundant melt and fluid inclusions. Two generations of CO2-rich fluid inclusions are present in quartz-rich xenolith grains: early (Type I) inclusions related to partial melting of the host xenoliths, and late Type II inclusions related to the fluid trapping during xenolith ascent. Homogenisation temperatures of fluid inclusions correspond to two density intervals: 0.93-0.68 g/cm3 (Type I) and 0.47-0.26 g/cm3 (Type II). Early Type I fluid inclusions indicate trapping pressures around 6 kbar, which are representative for the levels of partial melting of crustal rocks and xenolith formation. Late Type II fluid inclusions show lower trapping pressures, between 1.7 kbar and 0.2 kbar, indicative for shallow magma rest and accumulation during ascent to the surface. Data suggest the presence of two magma reservoirs: the first is located at lower crustal depths (about 24 km), site of fractional crystallization, mixing with source derived magma, and various degrees of crustal assimilation. The second magma reservoir is located at shallow crustal depths (about 6 km), the site where magma rested for a short time before erupting.

scholarly journals Early Type II Endoleaks Are Associated With Late Type I and III Endoleaks and Rupture After Endovascular Aortic Aneurysm Repair

2021 ◽  
Vol 74 (4) ◽  
pp. e361-e362
Author(s):  
Asma Mathlouthi ◽  
Kevin Yei ◽  
Andrew Barleben ◽  
Joseph Lombardi ◽  
Mahmoud Malas
Keyword(s):  
Aortic Aneurysm ◽  
Type I ◽  
Type Ii ◽  
Early Type ◽  
Late Type ◽  
Endovascular Aortic Aneurysm Repair ◽  
Aneurysm Repair ◽  
Aortic Aneurysm Repair

Zircon U–Pb ages, major and trace elements, and Hf isotope characteristics of the Tiantangzhai granites in the North Dabie orogen, Central China: tectonic implications

2013 ◽  
Vol 151 (5) ◽  
pp. 916-937 ◽  
Author(s):  
XIN DENG ◽  
KUNGUANG YANG ◽  
ALI POLAT ◽  
TIMOTHY M. KUSKY ◽  
KAIBIN WU
Keyword(s):  
Partial Melting ◽  
Eastern China ◽  
Major And Trace Elements ◽  
Central China ◽  
Dabie Orogen ◽  
Crustal Rocks ◽  
The North ◽  
Granitic Magmatism ◽  
Two Peaks ◽  
Lower Crustal

AbstractCretaceous granites are widespread in the North Dabie orogen, Central China, but their emplacement sequence and mechanism are poorly known. The Tiantangzhai Complex in the North Dabie Complex is the largest Cretaceous granitic suite consisting of six individual intrusions. In this study, zircon U–Pb ages are used to constrain the crystallization and protolith ages of these intrusions. The Shigujian granite is a syn-tectonic intrusion with an age of 141 Ma. This granite was emplaced under a compressional regime. Oscillatory rims of zircons have yielded two peaks at 137±1 Ma and 125±1 Ma. The 137±1 Ma peak represents the beginning of orogenic extension and tectonic collapse, whereas the 125±1 Ma peak represents widespread granitic magmatism. Zircon cores have yielded concordant ages between 812 and 804 Ma, which indicate a crystallization age for the protolith. The Tiantangzhai granites show relatively high Sr contents and high La/Yb and Sr/Y ratios. The Shigujian granite has positive Eu anomalies resulting from partial melting of a plagioclase-rich source in an over-thickened crust. Correspondingly, in situ Lu–Hf analyses from zircons yield high negative εHf(t) values from −24.8 to −26.6, with two-stage Hf model ages from 2748±34 to 2864±40 Ma, suggesting that the magmas were dominantly derived from partial melting of middle to lower crustal rocks. The Dabie orogen underwent pervasive NW–SE extension at the beginning of the early Cretaceous associated with subduction of the Palaeo-Pacific plate beneath eastern China.

scholarly journals Mantle rock exposures at oceanic core complexes along mid-ocean ridges

Geologos ◽  
2015 ◽  
Vol 21 (4) ◽  
pp. 207-231 ◽  
Author(s):  
Jakub Ciazela ◽  
Juergen Koepke ◽  
Henry J.B. Dick ◽  
Andrzej Muszynski
Keyword(s):  
Partial Melting ◽  
Geophysical Methods ◽  
Ex Situ ◽  
Crustal Rocks ◽  
New Class ◽  
Ocean Ridges ◽  
Common Structure ◽  
Spreading Ridges ◽  
Slow Spreading ◽  
Lower Crustal

Abstract The mantle is the most voluminous part of the Earth. However, mantle petrologists usually have to rely on indirect geophysical methods or on material found ex situ. In this review paper, we point out the in-situ existence of oceanic core complexes (OCCs), which provide large exposures of mantle and lower crustal rocks on the seafloor on detachment fault footwalls at slow-spreading ridges. OCCs are a common structure in oceanic crust architecture of slow-spreading ridges. At least 172 OCCs have been identified so far and we can expect to discover hundreds of new OCCs as more detailed mapping takes place. Thirty-two of the thirty-nine OCCs that have been sampled to date contain peridotites. Moreover, peridotites dominate in the plutonic footwall of 77% of OCCs. Massive OCC peridotites come from the very top of the melting column beneath ocean ridges. They are typically spinel harzburgites and show 11.3–18.3% partial melting, generally representing a maximum degree of melting along a segment. Another key feature is the lower frequency of plagioclase-bearing peridotites in the mantle rocks and the lower abundance of plagioclase in the plagioclase-bearing peridotites in comparison to transform peridotites. The presence of plagioclase is usually linked to impregnation with late-stage melt. Based on the above, OCC peridotites away from segment ends and transforms can be treated as a new class of abyssal peridotites that differ from transform peridotites by a higher degree of partial melting and lower interaction with subsequent transient melt.

scholarly journals Present structure of the Near-Bug area: conditions of formation and history of development

2021 ◽  
Vol 43 (2) ◽  
pp. 96-115
Author(s):  
O.V. Usenko
Keyword(s):  
Partial Melting ◽  
Main Part ◽  
Solidus Temperature ◽  
Age Determination ◽  
Granulite Facies ◽  
Geological Structure ◽  
General Sequence ◽  
Crustal Rocks ◽  
The Moment ◽  
Lower Crustal

General sequence establishment of geological Precambrian events and associating formations, which were created in them, to the results of isotope age definition, is the task, which has no single valued solution for southwestern part of the Ukrainian Shield. Important is to create a general development model, which will describe the modern geological structure of an area, structural and textural rocks features, accounting PT-conditions in the Earth's crust during the Archean—Paleoproterozoic. Isotopic age determination demonstrates, that from the moment of protolith creation (not later than 3.75 billion years ago, up to 1.9 billion years ago), intrusion of mantle melts and partial melting of the lower crustal rocks, occurred many times over. Pobuzhie formation cannot be imagined, as a single process of accumulation, plunge, crumpling into folds and sedimentary strata metamorphism. It is necessary, to take into account, the plume (mantle) component of the general geodynamic process. In the structure of the Bug megablock and Golovanevskaya suture zone, two main structural plans are displayed. The main part of the territory displays a region of areal distribution of Archean enderbites (generated 2.8 billion years ago) and Proterozoic granites (generated 2.03 billion years ago). The paper compares the temperature distribution with depth, corresponding to the thermal model of the metamorphic temperatures found in the samples, and the solidus temperatures of the basic rocks. It is shown that at the time of the metamorphism development, 2.0 billion years ago, the rocks were at a depth of more than 20 km, and before that — at an even greater depth. During the Archean and Paleoproterozoic, the center of partial melting was repeatedly renewed here, since the temperatures were higher than the solidus temperature of gabbro. Metamorphic changes (and more often migmatization, partial melting and following crystallization in the granulite facies conditions) happened after the presence of the thermal asthenosphere on the core—mantle border, and were accompanied by bringing the substance from it. Therefore the main part of modern surface is folded by palingenic granites. In Archean and Paleoproterozoic the composition of substances were different. After 2.0 billion years ago the level of modern surface was located higher. The second structural plan is presented with vertical structures, building of which often close to concentrically zonal or linear monoclinal. They are confined to fault zones and nodes of their intersections. These structures contain rock complexes, which did not occur until 2.0 billion years ago on any craton in the world.

scholarly journals The OH Circumstellar Maser in Late-Type Stars

1980 ◽  
Vol 87 ◽  
pp. 549-550 ◽  
Author(s):  
Nguyen-Q-Rieu ◽  
V. Bujarrabal ◽  
J. Guibert ◽  
A. Omont
Keyword(s):  
Colour Index ◽  
Type I ◽  
The Sun ◽  
Type Ii ◽  
Late Type ◽  
Dust Shell ◽  
Ir Sources ◽  
Mira Variables

A recent investigation based upon the OH luminosity distribution (Nguyen-Q-Rieu et al. 1979) has shown that Type I OH sources associated with Mira variables (OH Miras) are weak OH sources and are therefore only detected within ∼1 kpc from the Sun. Type II OH-Miras, which are more intense and rarer than Type I OH-Miras, are probably more distant objects. The group of unidentified Type II OH-IR sources probably consists of Type II OH-Miras of high OH luminosity. The IR colour index, which is usually higher for Type II sources, suggests that they have a colder and denser dust shell.

scholarly journals Late Type II Endoleaks After Endovascular Aneurysm Repair Require Intervention More Frequently Than Early Type II Endoleaks

2016 ◽  
Vol 64 (3) ◽  
pp. 835
Author(s):  
Danielle M. Pineda ◽  
Samuel Tyagi ◽  
Douglas A. Troutman ◽  
Matthew J. Dougherty ◽  
Keith D. Calligaro
Keyword(s):  
Endovascular Aneurysm Repair ◽  
Type Ii ◽  
Early Type ◽  
Late Type ◽  
Aneurysm Repair

scholarly journals Late type II endoleaks after endovascular aneurysm repair require intervention more frequently than early type II endoleaks

2018 ◽  
Vol 67 (2) ◽  
pp. 449-452 ◽  
Author(s):  
Danielle M. Pineda ◽  
Keith D. Calligaro ◽  
Sam Tyagi ◽  
Douglas A. Troutman ◽  
Matthew J. Dougherty
Keyword(s):  
Endovascular Aneurysm Repair ◽  
Type Ii ◽  
Early Type ◽  
Late Type ◽  
Aneurysm Repair

A new technique in neutron activation analysis of Na/K ratios of fluid inclusions and its application to the gold–quartz veins at the O'Brien mine, Quebec, Canada

1977 ◽  
Vol 14 (12) ◽  
pp. 2760-2770 ◽  
Author(s):  
K. M. Krupka ◽  
H. Ohmoto ◽  
F. E. Wickman
Keyword(s):  
Neutron Activation ◽  
Fluid Inclusions ◽  
Atomic Ratio ◽  
Type I ◽  
Type Ii ◽  
Two Phase ◽  
Analytical Technique ◽  
Quartz Veins ◽  
Type Iv ◽  
A New Technique

A new analytical technique which employs hydrated antimony pentoxide to selectively remove Na from Na–K–Cl mixed fluids was successfully tested. With this technique, the uncertainty in the K determination of inclusion fluids by neutron activation analyses can be reduced to less than ± 10% compared to greater than ± 20% uncertainty which is typical in the conventional techniques.Na/K ratios of fluid inclusions in 14 quartz samples from gold–quartz veins at the O'Brien mine. Quebec, Canada were determined using this technique. The Na/K atomic ratio of the samples ranges from 0.9 ± 0.1 to 24.3 ± 3.9. Optical examinations of the fluid inclusions indicate that the variation in the Na/K ratios is caused by the presence of varying proportions of four different types of fluid inclusions: type I (pregold mineralization fluids: CO2 rich), type II (gold mineralizing fluids showing evidence of boiling at temperatures of 380°–300 °C), type III (postgold mineralization fluids; vapor – liquid two phase inclusions), and type IV (postgold mineralization fluids; halite bearing), Type II fluid inclusions appear to have Na/K atomic ratios of approximately 1.0, while type IV inclusions show Na/K ratios of over 24.

Heat-Etching with a Bullivant Type II Simple Freeze-Cleave Device

1970 ◽  
Vol 28 ◽  
pp. 106-107 ◽  
Author(s):  
Ronald S. Weinstein ◽  
N. Scott McNutt
Keyword(s):  
New Zealand ◽  
General Hospital ◽  
Massachusetts General Hospital ◽  
Type I ◽  
Type Ii ◽  
Collaborative Effort ◽  
Temperature And Pressure ◽  
The University

The Type I simple cold block device was described by Bullivant and Ames in 1966 and represented the product of the first successful effort to simplify the equipment required to do sophisticated freeze-cleave techniques. Bullivant, Weinstein and Someda described the Type II device which is a modification of the Type I device and was developed as a collaborative effort at the Massachusetts General Hospital and the University of Auckland, New Zealand. The modifications reduced specimen contamination and provided controlled specimen warming for heat-etching of fracture faces. We have now tested the Mass. General Hospital version of the Type II device (called the “Type II-MGH device”) on a wide variety of biological specimens and have established temperature and pressure curves for routine heat-etching with the device.

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