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

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.

External calibrator in global signal experiment for detection of the epoch of reionization

We present a conceptual design study of external calibrators in the 21 cm experiment towards detecting the globally averaged radiation of the epoch of reionization (EoR). Employment of external calibrator instead of internal calibrator commonly used in current EoR experiments allows removing instrumental effects such as beam pattern, receiver gain and instability of the system if the conventional three-position switch measurements are implemented in a short time interval. Furthermore, in the new design the antenna system is placed in an underground anechoic chamber with an open/closing ceiling to maximally reduce the environmental effect such as RFI and ground radiation/reflection. It appears that three of the four external calibrators proposed in this paper, including two indoor artificial transmitters and one outdoor celestial radiation (the Galactic polarization), fail to meet our purpose. Diurnal motion of the Galactic diffuse emission turns out to be the most probable source as an external calibrator, for which we have discussed the observational strategy and the algorithm of extracting the EoR signal.

The Sulfide/Silicate Coefficients of Nd and Sm: Geochemical “Fingerprints” for the Syn- and Epigenetic Cu-Ni-(PGE) Ores in the NE Fennoscandian Shield

One of the current directions of the Sm-Nd isotope systematics development is a dating of the ore process using sulfide minerals. Yet, the issue of the existence of rare earth elements (REE) in sulfides is still a matter for discussion. Sulfides from ore-bearing rocks of Proterozoic (2.53–1.98 Ga) Cu-Ni and platinum group elements (PGE) deposits of the Fennoscandian Shield were studied. It is found that the most probable source of REE in sulfide minerals from Cu-Ni-PGE complexes could be submicronic fluid inclusions, which are trapped at the mineral crystallization stage. In such a case, fluid or melt inclusions are specimens of the syngenetic parental melt, from which the base mineral formed, and these reflect a composition of the parental fluid. The mineral–rock partition coefficients for Nd and Sm can be used as “fingerprints” for individual deposits, and these are isotope-geochemical indicators of the ore-caused fluid that is syngenetic to sulfide. Moreover, the DNd/DSm ratio for various sulfide minerals can be used as a prospective geochemical tool for reconstructing a mineral formation sequence in ore complexes. On the other hand, differences in isotope compositions of sulfide neodymium could be markers of some ore-caused fluids and related to certain generations of sulfide minerals.

Development of a Backward–Forward Stochastic Particle Tracking Model for Identification of Probable Sedimentation Sources in Open Channel Flow

As reservoirs subject to sedimentation, the dam gradually loses its ability to store water. The identification of the sources of deposited sediments is an effective and efficient means of tackling sedimentation problems. A state-of-the-art Lagrangian stochastic particle tracking model with backward–forward tracking methods is applied to identify the probable source regions of deposited sediments. An influence function is introduced into the models to represent the influence of a particular upstream area on the sediment deposition area. One can then verify if a specific area might be a probable source by cross-checking the values of influence functions calculated backward and forward, respectively. In these models, the probable sources of the deposited sediments are considered to be in a grid instead of at a point for derivation of the values of influence functions. The sediment concentrations in upstream regions must be known a priori to determine the influence functions. In addition, the accuracy of the different types of diffusivity at the water surface is discussed in the study. According to the results of the case study of source identification, the regions with higher sediment concentrations computed by only backward simulations do not necessarily imply a higher likelihood of sources. It is also shown that from the ensemble results when the ensemble mean of the concentration is higher, the ensemble standard deviation of the concentration is also increased.

Rutile Mineral Chemistry and Zr-in-Rutile Thermometry in Provenance Study of Albian (Uppermost Lower Cretaceous) Terrigenous Quartz Sands and Sandstones in Southern Extra-Carpathian Poland

The geochemistry of detrital rutile grains, which are extremely resistant to weathering, was used in a provenance study of the transgressive Albian quartz sands in the southern part of extra-Carpathian Poland. Rutile grains were sampled from eight outcrops and four boreholes located on the Miechów, Szydłowiec, and Puławy Segments. The crystallization temperatures of the rutile grains, calculated using a Zr-in-rutile geothermometer, allowed for the division of the study area into three parts: western, central, and eastern. The western group of samples, located in the Miechów Segment, is characterized by a polymodal distribution of rutile crystallization temperatures (700–800 °C; 550–600 °C, and c. 900 °C) with a significant predominance of high-temperature forms, and with a clear prevalence of metapelitic over metamafic rutile. The eastern group of samples, corresponding to the Lublin Area, is monomodal and their crystallization temperatures peak at 550–600 °C. The contents of metapelitic to metamafic rutile in the study area are comparable. The central group of rutile samples with bimodal distribution (550–600 °C and 850–950 °C) most likely represents a mixing zone, with a visible influence from the western and, to a lesser extent, the eastern group. The most probable source area for the western and the central groups seems to be granulite and high-temperature eclogite facies rocks from the Bohemian Massif. The most probable source area for the eastern group of rutiles seems to be amphibolites and low temperature eclogite facies rocks, probably derived from the southern part of the Baltic Shield.

PICTURING PARLIAMENT: THE GREAT SEAL OF THE COMMONWEALTH AND THE HOUSE OF COMMONS

Presenting research conducted by the ‘St Stephen’s Chapel, Westminster’ project at the University of York, this article focuses on the Great Seal devised in 1649 and re-issued in 1651 to enable the Commonwealth to function following the execution of Charles i. As a familiar and ancient image of monarchy, the Great Seal posed an obvious challenge to the authority of the Rump Parliament. A radical new design, authorised by parliamentary committee and executed by engraver Thomas Simon, replaced royal iconography with images of popular sovereignty and nationhood: a map of England and Ireland on the obverse of the Seal, and the interior of the House of Commons chamber (formerly St Stephen’s Chapel) on the reverse. The result was a striking evocation of political authority located in the House of Commons and deriving from the English people. Engravings of the Commons chamber, in circulation since the 1620s, are identified as a probable source for Simon’s work. The Great Seal also re-asserted England’s dominion over Ireland and the waters surrounding the British Isles. Overall, this article argues for continuity as well as alteration in the iconography of the Great Seal of England, at a time of revolutionary political change.

A new Source on the Relationship between Hulun Buir and Outer Mongolia in 1912—1915

A little-known source — the manuscript “Historical information on the fragility of the political situation of Hulunbuir”, stored in the State Archives of the Irkutsk region is considered. Description of the manuscript, clarification of its dating, determination of the probable source base was performed by the author of the article. A comparative analysis of the historical facts presented in the manuscript was carried out. It was found that in the first two sentences the anonymous author outlined the essence of the uncertain situation that developed with the annexation of Hulun Buir to Outer Mongolia in 1912. Other components of the text are characterized: little-known information about the trip to Urga of the Bargut lama Lobsanchjamba and then about the visit of the delegation of Hulun-Buir; data on the meeting of the delegates with the Russian consul V. F. Lyuba and a description of his reaction to the fact of the annexation of Hulun-Buir to Outer Mongolia; finally, it is said about the disappointment of the ruler of Hulun-Buir — Shenfu, who realized the dependence of Hulun-Buir on the dependent, in turn, Outer Mongolia, etc. An analysis of the contents of the last page of the manuscript allows us to conclude that part of the Hulunbuir officials, close to the Manchus, expressed open dissatisfaction with the situation. The author of the article suggests that some of the Daurian officials, unlike the Barguts, who sincerely believed in the creation of a unified Mongolian state, tended to restore the Manchu dynasty and were unhappy with the unclear future of Hulun Buir.