scholarly journals Magma Mingling in Kimberlites: Evidence from the Groundmass Cocrystallization of Two Spinel-Group Minerals

Minerals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 829
Author(s):  
Jingyao Xu ◽  
Joan Melgarejo ◽  
Qiuli Li ◽  
Lisard Abat ◽  
Montgarri Castillo-Oliver
Keyword(s):  
Sensu Stricto ◽  
Melt Crystallization ◽  
Magma Mingling ◽  
Paragenetic Sequence ◽  
Petrographic Study ◽  
Late Stages ◽  
Low Activity ◽  
Primary Minerals

We present the results of a detailed petrographic study of fresh coherent samples of the Menominee kimberlite sampled at site 73, located in Menominee County, MI, USA. Our objective is to account for its unusual and complex paragenetic sequence. Several generations of olivine, ilmenite, and spinel-group minerals are described. Early olivine and ilmenite are xenocrystic and were replaced or overgrown by primary minerals. Zoned microcrysts of olivine have a xenocrystic core mantled by a first rim in which rutile, geikielite, and spinel s.s. (spinel sensu stricto) cocrystallized. The in situ U–Pb dating of a microcryst of primary rutile yielded 168.9 ± 4.4 Ma, which was interpreted as the age of emplacement. The groundmass consists of olivine, spinel s.s., a magnesian ulvöspinel–ulvöspinel–magnetite (MUM) spinel, calcite, and dolomite. An extremely low activity of Si is suggested by the crystallization of spinel s.s. instead of phlogopite in the groundmass. The presence of djerfisherite microcrysts indicates high activities of Cl and S during the late stages of melt crystallization. The occurrence of two distinct spinel-group minerals (spinel s.s. and qandilite-rich MUM) in the groundmass is interpreted as clear evidence of the mingling of a magnesiocarbonatitic melt with a dominant kimberlitic melt.

scholarly journals GENESIS AND PHYSICAL CHARACTERISTICS OF THE NEOGENE RED BEDS FROM THE CEDARHILS OF THESSALONIKI, MACEDONIA , GREECE

2018 ◽  
Vol 36 (2) ◽  
pp. 708 ◽  
Author(s):  
A. Tsirambides
Keyword(s):  
Clay Minerals ◽  
Urban Forest ◽  
Clay Fraction ◽  
Eastern Mediterranean Region ◽  
Physical Characteristics ◽  
Coarse Grained ◽  
Red Beds ◽  
Primary Minerals ◽  
In Situ Weathering

The genesis and the physical characteristics of the Neogene red beds of the cedar hills surrounding Thessaloniki are studied in this paper. The peri-urban forest, which covers these hills, has a 3,022 ha area. The topographic relief is smooth and is divided in eight small drainage basins, tapped through small creeks. The elevation of the surrounding hills varies between 85 and 560 m. The dominant land slopes vary between 20 and 55%. All the samples are coarse grained, poorly sorted and friable and present earthy lustre and red colour because of the extensive presence of iron oxides. Angular to sub-angular rock fragments derived from the metamorphic bedrock are very common. Petrographically, the studied red beds belong to the clayey sands. The extended presence (41-66%) of coarse silt and sand size grains (>20 pm) in the samples suggests a mild intensity of in situ weathering of the bedrock. X-ray diffraction analysis of the coarsest fractions 250-20 pm and 20-2 μιτι revealed in decreasing abundance the presence of quartz, feldspars, epidote, micas, chlorite, pyroxenes, amphiboles, and talc. These fractions contain the 2M polytype of mica, while in the fraction <2 pm the 1Μα polytype of illite predominates. In the clay fraction (<2 pm) illite, smectite, and chlorite predominate. The presence of mixed-layer minerals is limited, testifying the almost complete character of hydrolysis of the primary minerals. The formation of red beds took place on low relief land under alternating wet and dry seasons, which prevail in the eastern Mediterranean region since Neogene. The clay minerals are the in situ weathering products of the primary minerals of the greenschists, gneisses and gabbros predominating in the studied area. The extensive presence of clay size grains (11-26%) in the samples, their poor sorting, and their sub-angular morphology, indicate that the red beds are texturally immature. In addition, the abundance of feldspars and Fe-Mg minerals reflects mineralogical immaturity. The low relief and the long-lasting tectonic stability in the Thessaloniki district were essential for the significant thickness of the red beds. The oxygen isotope data of the <0.2 pm fraction (+18.2 to +18.8%o) confirm the pedogenic origin of the clay minerals present. The red beds studied present low plasticity with liquid limit (WÏ) 26.9 to 33.4% and plasticity index (lp) 9.1 to 17.3%. In addition, they have high consolidation index (lc) values (1.03 to 2.28). The swelling potential is low to medium and the activity varies between 0.5 and 1.0. The consolidation and induration degree of the samples analyzed is low, because of the great range of their mineralogical composition and the mild conditions of pressure and temperature to which they have been submitted. The studied red beds are not considered problematic for the foundation of various constructions on them.

scholarly journals Palaeoecology and Archaeology of the Kärlich–Seeufer Open-Air Site (Middle Pleistocene) in the Central Rhineland, Germany

1996 ◽  
Vol 46 (3) ◽  
pp. 319-334 ◽  
Author(s):  
Sabine Gaudzinski ◽  
Felix Bittmann ◽  
Wolfgang Boenigk ◽  
Manfred Frechen ◽  
Thijs Van Kolfschoten
Keyword(s):  
Boreal Forests ◽  
Archaeological Site ◽  
Sensu Stricto ◽  
Middle Pleistocene ◽  
Recent Analysis ◽  
Small Lake ◽  
Wooden Structure ◽  
Archaeological Sample

The Kärlich–Seeufer archaeological site in Germany's central Rhineland was excavated between 1980 and 1992. The site provides evidence for hominid activity during a Middle Pleistocene interglaciation known up to now only from the Kärlich clay pit and therefore defined as the Kärlich Interglaciation, which is considered to be post-Cromer IV and pre-Holstein (sensu stricto) in age. The site is characterized by Acheulean artifacts, a fauna dominated by Elephas (Palaeoloxodon) antiquus, and a unique and outstanding preservation of wooden and other palaeobotanical remains. Assuming all finds are associated, the site previously was interpreted as an elephant hunting camp with a wooden structure, together with wood and bone implements preserved in situ. Recent analysis of the same features has shown that the site can also be interpreted as a reworked archaeological sample. Hominid occupation occurred in the vicinity of a small lake with prevailing meso-oligotrophic conditions. Expanding boreal forests and fen vegetation characterized the landscape.

scholarly journals Spatiotemporal Expression of Anticoagulation Factor Antistasin in Freshwater Leeches

2019 ◽  
Vol 20 (16) ◽  
pp. 3994 ◽  
Author(s):  
Hee-Jin Kwak ◽  
Jeong-Su Park ◽  
Brenda Irene Medina Jiménez ◽  
Soon Cheol Park ◽  
Sung-Jin Cho
Keyword(s):  
Hedgehog Signaling ◽  
Signal Transduction Pathway ◽  
The Body ◽  
Spatial Expression ◽  
Downstream Target ◽  
Spatiotemporal Expression ◽  
Stage 4 ◽  
Segment Polarity ◽  
Late Stages

Antistasin, which was originally discovered in the salivary glands of the Mexican leech Haementeria officinalis, was newly isolated from Helobdella austinensis. To confirm the temporal expression of antistasin during embryogenesis, we carried out semi-quantitative RT-PCR. Hau-antistasin1 was uniquely expressed at stage 4 of the cleavage and was strongly expressed in the late stages of organogenesis, as were other antistasin members. In order to confirm the spatial expression of antistasin, we performed fluorescence in situ hybridization in the late stages of organogenesis. The expression of each antistasin in the proboscis showed a similar pattern and varied in expression in the body. In addition, the spatial expression of antistasin orthologs in different leeches showed the possibility of different function across leech species. Hau-antistasin1 was expressed in the same region as hedgehog, which is a known mediator of signal transduction pathway. Hau-antistasin1 is probably a downstream target of Hedgehog signaling, involved in segment polarity signal pathway.

U–Pb geochronology of minerals from the Midwest uranium deposit, northern Saskatchewan

1984 ◽  
Vol 21 (6) ◽  
pp. 642-648 ◽  
Author(s):  
H. Baadsgaard ◽  
G. L. Cummino ◽  
J. M. Worden
Keyword(s):  
First Generation ◽  
Second Generation ◽  
Uranium Deposit ◽  
Paragenetic Sequence ◽  
Secondary Material ◽  
Basement Rocks ◽  
Northern Saskatchewan ◽  
Host Rocks ◽  
Sampling Problems ◽  
Late Stages

Analyses of U/Pb ratios in 30 microsamples of pitchblende and coffinite from the Midwest uranium deposit in northern Saskatchewan, as well as two altered zircons from host rocks, indicate an age of mineralization for primary pitchblende of 1328 ± 17 Ma. The primary material was remobilized at 1110 ± 28 Ma, forming the second generation of pitchblende and coffinite. First-generation pitchblende appears to have lost Pb either by diffusion or by a series of episodic losses at 300–100 Ma, whereas the secondary material proved more susceptible to Pb loss in the recent past.There is evidence of migration of pitchblende downwards into the basement rocks under the deposit at least as recently as 700 Ma ago, but we have been unable to date with certainty any late stages in the paragenetic sequence because of sampling problems associated with the small size of material clearly identifiable as stage 3 or 4 of the paragenetic sequence of Wray et al.

scholarly journals The chicken c-erbA proto-oncogene is preferentially expressed in erythrocytic cells during late stages of differentiation.

1987 ◽  
Vol 7 (7) ◽  
pp. 2416-2424 ◽  
Author(s):  
D Hentzen ◽  
A Renucci ◽  
D le Guellec ◽  
M Benchaibi ◽  
P Jurdic ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Life Span ◽  
Blood Cells ◽  
Low Levels ◽  
High Level ◽  
Nuclease Mapping ◽  
Kidney Liver ◽  
Late Stages ◽  
Different Tissues

We analyzed the expression of the c-erbA proto-oncogene in different tissues of chicken embryos. c-erbA transcripts were found at low levels in the lung, kidney, liver, and heart and in high amounts in embryonic blood cells. Nuclease mapping assays proved that these transcripts were true c-erbA transcripts. In situ hybridization on fractionated embryonic blood cells showed that c-erbA transcripts were predominantly found in erythroblasts, particularly during the final step of differentiation. Life span analysis of c-erbA mRNAs revealed their relative instability, demonstrating that the high level of c-erbA transcripts in embryonic erythroblasts was not the result of passive accumulation. These results suggest that the c-erbA genes play some role in erythrocyte differentiation.

In situ CD14 expression in biliary atresia: Comparison between early and late stages

2001 ◽  
Vol 36 (1) ◽  
pp. 240-243 ◽  
Author(s):  
Abul Faiz Kabir Uddin Ahmed ◽  
Masaki Nio ◽  
Haruo Ohtani ◽  
Hiroshi Nagura ◽  
Ryoji Ohi
Keyword(s):  
Biliary Atresia ◽  
Late Stages

scholarly journals Effect of Temperature and Time on Nickel Aluminide Coating Deposition

2018 ◽  
Vol 37 (4) ◽  
pp. 491-496 ◽  
Author(s):  
Ali Dad Chandio ◽  
Shahid Hussain Abro
Keyword(s):  
Nickel Aluminide ◽  
Linear Trend ◽  
Aluminide Coating ◽  
Chemical Vapor ◽  
Effect Of Temperature ◽  
Chemical Vapor Deposition Method ◽  
X Ray Diffraction ◽  
Initial Stage ◽  
Low Activity

The βNiAl coating was deposited onto Nickel based CMSX-4 superalloy by in-situ CVD (Chemical Vapor Deposition) method. Main focus of this contribution was to study the influence of aluminizing time and temperature on the microstructure and thickness of the coating; this was followed by examination by XRD (X-Ray Diffraction), electron microscope. Results suggest that an incremental variation in temperature alters the coating activities from HA (High Activity) to LA (Low Activity). This is exhibited by the resultant CT (Coating Thickness) since HA coatings are thicker than LA counterparts. The microstructure of the coating formed at low temperature (or HA ones) showed a large amount of α-Cr precipitates while one formed at high temperature (or LA ones) exhibited lower amounts of such precipitates. Moreover, incremental aluminizing time showed linear trend of CT at initial stage, thereafter (10 hrs) it leveled off. Whereas it does not affect microstructure of the coating

scholarly journals Specificity of Infection-Induced Immunity amongBorrelia burgdorferi Sensu Lato Species

1999 ◽  
Vol 67 (1) ◽  
pp. 36-42 ◽  
Author(s):  
Stephen W. Barthold
Keyword(s):  
Protective Immunity ◽  
Passive Immunization ◽  
Sensu Stricto ◽  
Low Doses ◽  
Active Infection ◽  
Borrelia Garinii ◽  
High Doses ◽  
Species Specific ◽  
Late Stages ◽  
Induced Immunity

ABSTRACT The specificity of infection-induced immunity in mice infected with cultured or host-adapted Borrelia burgdorferi sensu lato, the agent of Lyme disease, was examined. Sera obtained from mice following infection with high and low doses of cultured B. burgdorferi sensu stricto, transplantation of infected tissue (host-adapted spirochetes), or tick-borne inoculation all showed protective activity in passive immunization assays. Infection and disease were similar in mice infected with cultured spirochetes or by transplantation. Thus, the adaptive form of inoculated spirochetes did not influence the immune response during active infection. Mice infected with B. burgdorferi sensu stricto and then cured of infection with an antibiotic during early or late stages of infection were resistant to challenge with high doses of homologous cultured spirochetes for up to 1 year. In contrast, actively immune mice infected with different Borrelia species (B. burgdorferi sensu lato, B. burgdorferi sensu stricto cN40, Borrelia afzelii PKo, and Borrelia garinii PBi) and then treated with an antibiotic were resistant to challenge with cultured homologous but not heterologous spirochetes. Similar results were achieved for actively immune mice challenged by transplantation and by passive immunization with sera from mice infected with each of the Borrelia species and then challenged with cultured spirochetes. Arthritis and carditis in mice that had immunizing infections with B. afzelii and B. garinii and then challenged by transplantation with B. burgdorferi sensu stricto were equivalent in prevalence and severity to those in nonimmune recipient mice. These results indicate that protective immunity and disease-modulating immunity that develop during active infection are universal among species related to B. burgdorferi sensu lato but are species specific.

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