scholarly journals Ore Petrography, Mineralogical and Chemical Composition of New Iron Meteorite (Al-Sherqat Meteorite) from Iraq

2021 ◽  
Vol 54 (2E) ◽  
pp. 1-11
Author(s):  
Awadh Salih
Keyword(s):  
Chemical Composition ◽  
Total Mass ◽  
Iron Meteorite ◽  
Uniform Structure ◽  
Polished Section ◽  
Iron Meteorites ◽  
Northern Iraq ◽  
The Core ◽  
Probable Source ◽  
Continuous Plate

The meteorite with a single total mass of 630 gm as a visible meteorite has fallen on 22 March 2021, at 10:00 a.m. in Al-Sherqat subdistrict within Salah Al-Din, northern Iraq; and therefore, was named Al-Sherqat meteorite by the authors. It is characterized by a uniform structure of coherent and medium degree of malleability. It is of a well-crystalline structure and not homogeneous in composition. The Al-Sherqat meteorite is composed of metallic phases of 7.6 gm/cm3 density exhibiting an oriented intergrowth of kamacite (α-FeNi) with taenite showing a Widmanstätten pattern on an etched polished section with the finest octahedrite kamacite bandwidth of less than 0.2 mm. It is composed of Fe (86.9 wt%), Ni (9.63 wt%), P (1.31 wt%), S (0.628 wt%), Ti (0.623 wt%), Co (0.446 wt%), Mo (0.146 wt%), Cr (0.103 wt%), Cu (0.141 wt%), V (300 ppm), Nb (220 ppm), W (53 ppm), Ag (50 ppm), Pb (30 ppm), Zn (20 ppm), Sb (16 ppm), Sn (10 ppm) and As (3 ppm). Al-Sherqat meteorite was structurally classified as an iron meteorite belongs to the plessitic group (Opl)) with octahedrite finest bands (less than 0.2 mm) of the kamacite lamellae. Kamacite platelets in Al-Sherqat meteorite are almost not a continuous plate network. Chemically, it belongs to the IIC type of magmatic group based on the amount of nickel (9.63%), where IIC is typically octahedrites has 9.3 – 11.5% Ni. The presence of kamacite, taenite, schreibersite, daubréelites, pentlandite, chromite, and wusite in Al-Sherqat meteorite are in accordance with IIC group of the iron meteorites. Al-Sherqat meteorite belongs to M-type considering a metallic core fragmented by impact asteroid. The most probable source of this meteorite is the core of an asteroid that melted early in its history.

Hydrogeochemical and isotopic characterization of groundwater at Žitný Island (SW Slovakia)

2015 ◽  
Vol 46 (6) ◽  
pp. 929-942 ◽  
Author(s):  
Z. Ženišová ◽  
P. P. Povinec ◽  
A. Šivo ◽  
R. Breier ◽  
M. Richtáriková ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Surface Water ◽  
Danube River ◽  
Water Isotopes ◽  
Anthropogenic Contamination ◽  
The Danube River ◽  
The Core ◽  
Groundwater Reservoir ◽  
Isotopic Characterization

Hydrogeochemical investigations and spatial variations studies on the distribution of water isotopes and radiocarbon in the groundwater of Žitný Island (Rye Island) were carried out. Žitný Island represents the largest groundwater reservoir in Central Europe (about 10 Gm3). The chemical composition of the groundwater of Žitný Island depends mainly on the chemical composition of Danube water, as well as on the length of its infiltration from the Danube River. The groundwater is characterized by potamogenic mineralization, and its chemical composition is influenced by anthropogenic contamination. Sub-surface water profiles showed enriched δ18O levels up to around 20 m water depth, and depleted values for deeper waters. The observed isotopic composition of the groundwater is similar to Danube water, suggesting that the Danube River is the main source of the Žitný Island groundwater. The core of the sub-surface 14C profile represents contemporary groundwater with 14C values above 80 pMC.

scholarly journals On Some Peculiar Features in the Sequences of the Old Open Star Clusters

1974 ◽  
Vol 59 ◽  
pp. 109-111
Author(s):  
A. Maeder
Keyword(s):  
Chemical Composition ◽  
Stellar Evolution ◽  
Main Sequence ◽  
Star Clusters ◽  
Open Star Clusters ◽  
Hydrogen Burning ◽  
The Core ◽  
Open Star ◽  
Solar Type ◽  
Good Agreement

In spite of the rather good agreement between the theory of stellar evolution and the observations, there exist some difficulties when one compares closely the sequences of open star clusters and the theoretical isochrones. Several, if not all, of the old open star clusters seem to be concerned, especially those which are accurately measured, namely Praesepe, NGC 2360, 752, 3680 and M67. The problem concerns the gap occuring in the HR diagram at the end of the phase of hydrogen burning in the core; it corresponds to the phase of hydrogen exhaustion (or of overall contraction). The sequence of M67 has been studied by Racine (1971) and Torres-Peimbert (1971). The well apparent gap is located farther from the zero-age main sequence than indicated by the models and the hook towards a larger Teff predicted during this phase is not observed. Differences in chemical composition may not be held responsible for these anomalies. From Torres-Peimbert's models, it may be assumed that neither solar type, nor super metal rich composition are able to reduce the discrepancies. As a further illustration, let us mention the case of NGC 752. In Table I, the main features related to the gap are examined: the disagreement, like in M67, essentially concern features 1 and 2. The observations are based on a recent study of Grenon and Mermillod (1973) and on Bell's data (1972). Bell has also mentioned the existence of discrepancies. As in M67, the gap is too far from the zero-age main sequence and does not present any sudden turning towards a larger Teff.

scholarly journals Optical and X-ray observations of stellar winds in Wolf-Rayet binaries

1995 ◽  
Vol 163 ◽  
pp. 262-270
Author(s):  
A. M. Cherepashchuk
Keyword(s):  
Chemical Composition ◽  
Core Temperature ◽  
Stellar Winds ◽  
Radial Expansion ◽  
Core Radius ◽  
X Ray ◽  
The Core ◽  
Basic Conclusion ◽  
Helium Stars ◽  
Colliding Winds

New spectrophotometric, photometric and polarimetric observations of V444 Cygni confirm the basic conclusion that the WN5 star has a small core radius (rc < 4 R⊙) and a high core temperature (Tc > 60 000 K), which are characteristic of massive helium stars. Values of rc < 3 — 6 R⊙ and Tc > 70 000 — 90 000 K for the core of the WN7 star in the Cygnus X-3 system agree well with this conclusion. A clumping structure of WR winds is suggested. X-ray observations of colliding winds in WR+O binaries suggest radial expansion and anomalous chemical composition of WR winds.

Scanning Electron Microscopy And Electron Probe Microanalysis Of Extraterrestrial Materials

1999 ◽  
Vol 5 (S2) ◽  
pp. 2-3
Author(s):  
J. I. Goldstein
Keyword(s):  
Electron Microscopy ◽  
Low Temperatures ◽  
Electron Probe ◽  
Iron Meteorite ◽  
The Moon ◽  
Iron Meteorites ◽  
Slow Cooling ◽  
Electron Probe Microanalyzer ◽  
Extraterrestrial Materials ◽  
Scanning Electron

One of the first samples analyzed by Castaing in his electron probe microanalyzer (EPMA) some 50 years ago was an iron meteorite. The Widmanstatten pattern microstructure of iron meteorites can be observed at very low magnifications ( Fig. 1). These meteorites are ideal samples for microanalysis because of the Ni gradient which extends over 10 to 1000 microns in the parent taenite phase of these Fe-Ni samples (Fig. 3). The Ni gradient is the result of very slow cooling of the iron meteorite, in terms of millions of years, within a parent'asteroid.The scanning electron microscope (SEM) has been used to characterize the microstructure of meteorites, as well as samples from the moon and mars. For example, the microstructure of the dark etching taenite areas (T in Fig. 1) of the Carleton iron meteorite is shown in Fig 2. In this example, precipitates are observed along original martensite laths which form during the cooling of the iron meteorite at low temperatures.

scholarly journals The Origin of the RS CVn Binaries

1976 ◽  
Vol 73 ◽  
pp. 381-387 ◽  
Author(s):  
P. Biermann ◽  
D. S. Hall
Keyword(s):  
Angular Momentum ◽  
Star Formation ◽  
Total Mass ◽  
Total Angular Momentum ◽  
Main Sequence ◽  
Be Stars ◽  
Large Space ◽  
Single Star ◽  
The Core ◽  
Thermal Phase

We consider six possible origins for the RS CVn binaries based on the following possibilities. RS CVn binaries might now be either pre-main-sequence or post-main-sequence. A pre-main-sequence binary might not always have been a binary but might have resulted from fission of a rapidly rotating single pre-main-sequence star. The main-sequence counterparts might be either single stars or binaries.To decide which of the six origins is possible, we consider the following observed data for the RS CVn binaries: total mass, total angular momentum, lack of observed connection with regions of star formation, large space density, kinematical age, and the visual companion of WW Dra. In addition we consider lifetimes and space densities of single stars and other types of binaries.The only origin possible is that the RS CVn binaries are in a thermal phase following fission of a main-sequence single star. In this explanation the single star had a rapidly rotating core which became unstable due to the core contraction which made it begin to evolve off the main sequence. The present Be stars might be examples of such parent single stars.

GEOCHEMICAL INTERPRETATION OF SOME OILS AND CONDENSATES FROM THE DAMPIER SUB- BASIN OF WESTERN AUSTRALIA

1982 ◽  
Vol 22 (1) ◽  
pp. 179 ◽  
Author(s):  
I. Brikké
Keyword(s):  
Chemical Composition ◽  
Western Australia ◽  
Land Plant ◽  
Early Triassic ◽  
Normal Alkane ◽  
Geological Interpretation ◽  
The Core ◽  
Strong Affinity ◽  
Strong Emphasis ◽  
Deep Source

Twenty oils and condensates from the Dampier Sub-basin have been analysed for their gross composition and normal alkane distribution.The chemical composition (GLC traces) enables two groups to be distinguished:Oils and condensates low in C22 + n-alkanes. These are essentially found in the Rankin Platform. In this group, the sample from Eaglehawk 1 shows characteristics of a bacterially-altered product.Oils richer in C22 + n-alkanes. These are found in the Lewis Trough, but also in the Rankin Platform/Kendrew Terrace where subtle differences may suggest different origins.The geological interpretation puts strong emphasis on time of trapping. The oils and condensates of the first group (except at Angel) are trapped at the contact with the 'Main Unconformity'. Oils formed earlier than the Neocomian have been destroyed, altered (Eaglehawk 1) or trapped in deeper reservoirs, so that only mature to very mature hydrocarbons (low in C22 + n-alkanes) were available for trapping after sealing by Neocomian shales. Maturity considerations indicate that a deep source within the core of the Rankin Platform unit (Middle/Early Triassic Locker Shale and/or older) is the most likely generator of these hydrocarbons.The oils of the second group, on maturity grounds and to some extent on type correlation, may originate from Jurassic sources in the Lewis Trough. Some oils attributable to the second group are present on the Rankin Platform and/or Kendrew Terrace trapped by intraformational/fault seals and having the full composition of crudes; however, lower land-plant contribution inferred from the n-alkanes, suggests a 'Locker Shale' origin.The source of the Angel hydrocarbons is more enigmatic, but their strong affinity with the hydrocarbons from the Rankin Platform points to a similarity of origin.

scholarly journals Fe-Ni-P-S Melt Pockets in Elga IIE Iron Meteorite: Evidence for the Origin at High-Pressures Up to 20 GPa

Minerals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 616 ◽  
Author(s):  
Konstantin Litasov ◽  
Svetlana Teplyakova ◽  
Anton Shatskiy ◽  
Konstantin Kuper
Keyword(s):  
Experimental Data ◽  
Solid Solution ◽  
Important Implication ◽  
High Pressures ◽  
Bulk Composition ◽  
Parent Body ◽  
Iron Meteorite ◽  
Iron Meteorites ◽  
High Pressures And Temperatures ◽  
Melt Pockets

Here we report new data on high-pressure microstructures in Elga group IIE iron meteorites, made of solidified Fe-Ni-P-S melt pockets and microcrystalline aggregates, which could be formed only at high pressures and temperatures according to the experimental data. The bulk composition of the melt pockets and crystals correspond to the Fe3P-Fe3S solid solution with the closure of an immiscibility gap at pressures near 20 GPa in static experiments. Some other melt pockets fit with the Fe2S-Fe2P compositions, which could also correspond to high pressures and temperatures. The results suggest a late shock episode during the formation of the IIE iron parent body, which may be prior or due to the final disruption that caused the meteorite arrival to Earth. It also has an important implication to the shock features in other meteorites, such as ureilite.

scholarly journals Nucleation and Initial Growth of Garnet in Low-Grade Metamorphic Rocks of the Sanbagawa Metamorphic Belt, Kanto Mountains, Japan

Minerals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 292 ◽  
Author(s):  
Mutsuko Inui ◽  
Yumenosuke Wakai ◽  
Hiirou Sakuragi
Keyword(s):  
Chemical Composition ◽  
Size Distribution ◽  
Crystal Size ◽  
Crystal Size Distribution ◽  
Garnet Growth ◽  
Low Grade ◽  
Initial Growth ◽  
Metamorphic Belt ◽  
The Core ◽  
Log Normal

The beginning of the recrystallization of minerals within a subducting oceanic plate provides a valuable record of dehydration within the subduction zone. Pelitic schists of the Nagatoro area, Kanto Mountains, Japan, record the initial stages of garnet growth. Consequently, these rocks were studied to analyze garnet nucleation and growth during metamorphism of the Sanbagawa metamorphic belt, one of the world’s most comprehensively studied subduction complexes. The garnet grains are small, euhedral, and occur only within micaceous lamellae that define the schistosity. Crystal size distribution analyses revealed most of the garnet grains follow the log-normal size distribution, indicating that they formed in the same event. A few exceptionally large garnet grains exist that do not seem to follow the log-normal distribution. The latter garnet grains contain a rounded fragmental area with a different chemical composition inside the core. It is possible that detrital fragments of garnet contribute to the irregular crystal size distribution of garnet in the studied area. Many of the smaller (log-normal) garnet grains have relatively large, homogeneous Mn-rich cores. The lack of chemical zoning within the garnet cores suggests that they grew under constant pressure and temperature in response to overstepping of the garnet-in reaction. The chemical composition changes very sharply at the boundary between the core and the surrounding mantle. The size of the Mn-rich core is different from sample to sample, suggesting that the nucleation was controlled by the local chemical condition of each sample.

Planetesimal Capture by an Evolving Giant Gaseous Protoplanet

2012 ◽  
Vol 8 (S293) ◽  
pp. 263-269
Author(s):  
Morris Podolak ◽  
Nader Haghighipour
Keyword(s):  
Mass Distribution ◽  
Total Mass ◽  
Size Composition ◽  
Giant Planets ◽  
The Core ◽  
Last Stage ◽  
Core Accretion ◽  
Gaseous Envelope ◽  
Gas Drag ◽  
Probability Of Capture

AbstractBoth the core-accretion and disk-instability models suggest that at the last stage of the formation of a gas-giant, the core of this object is surrounded by an extended gaseous envelope. At this stage, while the envelope is contracting, planetesimals from the protoplanetary disk may be scattered into the protoplanets atmosphere and deposit some or all of their materials as they interact with the gas. We have carried out extensive simulations of approximately 104 planetesimals interacting with a envelope of a Jupiter-mass protoplanet including effects of gas drag, heating, and the effect of the protoplanets extended mass distribution. Simulations have been carried out for different radii and compositions of planetesimals so that all three processes occur to different degrees. We present the results of our simulations and discuss their implications for the enrichment of ices in giant planets. We also present statistics for the probability of capture (i.e. total mass-deposition) of planetesimals as a function of their size, composition, and closest approach to the center of the protoplanetary body.

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