Amphibole and plagioclase chemistry in two Proterozoic dyke swarms and its relation to the uplift history of the Kapuskasing Structural Zone

1992 ◽  
Vol 29 (8) ◽  
pp. 1791-1801 ◽  
Author(s):  
H. C. Palmer ◽  
R. L. Barnett
Keyword(s):  
Country Rock ◽  
Magnetic Polarity ◽  
Dyke Swarm ◽  
Limited Data ◽  
History Of ◽  
Magnetite Particles ◽  
Differential Uplift ◽  
Highly Correlated ◽  
Dyke Swarms ◽  
Lower Crustal

The gneisses of the Chapleau portion of the Kapuskasing Structural Zone (KSZ) and of the Wawa Gneiss Terrane (WGT) can be partitioned into subregions on the basis of magnetic polarity of 2.45 Ga Matachewan diabase dykes emplaced within them. West of the Ivanhoe Lake fault zone (ILFZ) the polarity sequence across the trend of the dyke swarm is normal–reverse–normal (N–R–N) over a traverse distance >100 km. Highly correlated with dyke N polarity is the presence of tea-coloured groundmass plagioclase and hornblende with high Al, Na, and Ti content. Reversely magnetized dykes within the WGT and in dykes of either polarity in regions far removed from the KSZ have groundmass plagioclase with hydrous alteration and relatively Al-poor amphiboles. Although N and R magnetized dykes have groundmass plagioclase with comparable Fe contents, the plagioclase of N dykes and Kapuskasing dykes in the highest grade country rock contain discrete, micrometre-sized, Ti-poor magnetite particles. The mineralogical variations are independent of whole-rock bulk chemistry and are ascribed to greater crystallization depth for N magnetized dykes. The magnitude of the amphibole compositional change in dykes at the western N–R boundary within the WGT is comparable to that across the ILFZ. The western N–R boundary is wholly within the WGT, whereas the ILFZ juxtaposes upper and lower crustal levels. As a consequence, only some of the differential uplift between the KSZ and the Abitibi belt can be accounted for in post-Matachewan dyke time. Limited data from the amphiboles in the 2.04 Ga east-northeast-trending Kapuskasing dykes suggest that this phase of faulting along these block boundaries postdates Kapuskasing dyke emplacement.

Pb, Nd, Sr isotopic composition of the Mesoproterozoic mafic intrusions (Udzha paleorift, Northern Siberia)

2020 ◽  
Author(s):  
Lidiia Shpakovich ◽  
Sergey Malyshev ◽  
Valeriy Savatenkov
Keyword(s):  
Isotopic Composition ◽  
Siberian Craton ◽  
Dyke Swarm ◽  
Mafic Dyke ◽  
Russian Science ◽  
Mafic Intrusions ◽  
Anabar Shield ◽  
History Of ◽  
Pb Isotopic Composition ◽  
Dyke Swarms

<p>Geodynamic reconstructions are largely based on information contained in mafic igneous rocks, including dykes and sills. The age and isotope-geochemical characteristics of such rocks are inevitable for understanding of geodynamic history of the Proterozoic cratons. The regions in Siberian Craton, where Precambrian mafic dyke swarms are known are following: Anabar Shield and Olenek Uplifts, Aldan-Stanovoi Shield, SE area of Siberian Craton, and smaller Uplifts on the SW margin of Siberian Craton.</p><p>The Udzha paleo-rift is located in the northern part of Siberian Craton between Anabar and Olenek Uplifts is also associated with mafic dyke swarm. These dykes cross-cut the pre-Neoproterozoic sedimentary successions. The age of the largest dyke in Udzha paleo-rift (Great Udzha Dyke) presented by medium-grained dolerite was determined to be 1386 ± 30 Ma (Malyshev et al., 2018).</p><p>We present new data of Sr, Nd and Pb isotopic composition on the Udzha paleo-rift dykes, determined by TIMS. The initial isotopic composition of Pb in the dykes was obtained using the leaching method by Savatenkov et al., 2019. The Sr isotopic composition of the dykes demonstrates substantial variation (εSr varies from 8.4 to 110.4). We do not consider this fact as a result of crust contamination, because Nd isotopic composition does not vary significantly (εNd varies from -1.4 to 0.7). Obtained results indicate that initial for the Udzha paleo-rift dykes melts were generated from two mantle reservoirs of DM and EMII-type. The initial Pb isotopic composition of the dykes reveals EMII source participation in the melts generation too (<sup>206</sup>Pb/<sup>204</sup>Pb varies from 16.133 to 16.266, <sup>207</sup>Pb/<sup>204</sup>Pb varies from 15.343 to 15.458). The presence of enriched component is likely associated with lithospheric mantle, metasomatized by fluids, derived from subducted terrigenous material.</p><p>The studies were supported by the Russian Science Foundation project No. 19-77-10048.</p><p>References</p><p>Malyshev, S. V., Pasenko A. M., Ivanov A. V., Gladkochub D. P., Savatenkov V. M., Meffre S., Abersteiner A., Kamenetsky V. S. & Shcherbakov V. D. (2018): Geodynamic Significance of the Mesoproterozoic Magmatism of the Udzha Paleo-Rift (Northern Siberian Craton) Based on U-Pb Geochronology and Paleomagnetic Data. – Minerals, 8(12), 555</p><p>Savatenkov V. M., Malyshev, S. V., Ivanov A. V., Meffre S., Abersteiner A., Kamenetsky V. S., Pasenko A. M. (2019): An advanced stepwise leaching technique for derivation of initial lead isotope ratios in ancient mafic rocks: A case study of Mesoproterozoic intrusions from the Udzha paleo-rift, Siberian Craton. – Chemical Geology, 528, 119253</p>

Paleomagnetism and U–Pb geochronology of the Lac de Gras diabase dyke swarm, Slave Province, Canada: implications for relative drift of Slave and Superior provinces in the PaleoproterozoicGeological Survey of Canada Contribution 20080350.

2009 ◽  
Vol 46 (5) ◽  
pp. 361-379 ◽  
Author(s):  
Kenneth L. Buchan ◽  
Anthony N. LeCheminant ◽  
Otto van Breemen
Keyword(s):  
Magnetic Polarity ◽  
Canadian Shield ◽  
Dyke Swarm ◽  
Superior Province ◽  
Igneous Complex ◽  
Contact Test ◽  
Slave Province ◽  
Formed Part ◽  
Dyke Swarms

Lac de Gras diabase dykes trend north to NNE across the central Slave Province of the Canadian Shield. U–Pb baddeleyite ages of 2023 ± 2 and 2027 ± 4 Ma are interpreted as dyke emplacement ages. These ages are similar to that of the Booth River igneous complex, exposed along the margins of Kilohigok Basin near the northern end of the dyke swarm. Ten paleomagnetic sites (from four to six dykes) yield a mean paleopole at 11.8°N, 92.1°W (dm = 8.4°, dp = 6.0°). A positive baked contact test where a Lac de Gras dyke crosscuts a NE-trending Malley dyke demonstrates that this pole is primary. It represents the first key Paleoproterozoic pole from the Slave Province and, hence, the first Paleoproterozoic Slave pole suitable for reconstructing paleocontinents. Although a direct comparison is not available with precisely dated paleopoles of identical age from other Archean cratons, a comparison is made with a sequence of precisely dated poles from Superior Province dyke swarms, including those 40–50 million years older and 25 million years younger. It yields two options depending on the relative magnetic polarity assumed for data from the two cratons. The two cratons were either at similar latitudes, but not in their present relative orientations, when the swarms were emplaced, or separated in latitude by ∼40°–60°. In either case, they may have drifted separately or formed part of a single (super)continent that subsequently broke up with the two cratons drifting separately to attain their present configuration. Additional key paleopoles are required to distinguish between these interpretations.

scholarly journals Low Nucleotide Diversity in Chimpanzees and Bonobos

Genetics ◽  
2003 ◽  
Vol 164 (4) ◽  
pp. 1511-1518 ◽  
Author(s):  
Ning Yu ◽  
Michael I Jensen-Seaman ◽  
Leona Chemnick ◽  
Judith R Kidd ◽  
Amos S Deinard ◽  
...  
Keyword(s):  
Nucleotide Diversity ◽  
Nuclear Dna ◽  
Demographic History ◽  
Nuclear Genome ◽  
Limited Data ◽  
Effective Population ◽  
East Central ◽  
Dna Diversity ◽  
History Of ◽  
Mtdna Diversity

Abstract Comparison of the levels of nucleotide diversity in humans and apes may provide much insight into the mechanisms of maintenance of DNA polymorphism and the demographic history of these organisms. In the past, abundant mitochondrial DNA (mtDNA) polymorphism data indicated that nucleotide diversity (π) is more than threefold higher in chimpanzees than in humans. Furthermore, it has recently been claimed, on the basis of limited data, that this is also true for nuclear DNA. In this study we sequenced 50 noncoding, nonrepetitive DNA segments randomly chosen from the nuclear genome in 9 bonobos and 17 chimpanzees. Surprisingly, the π value for bonobos is only 0.078%, even somewhat lower than that (0.088%) for humans for the same 50 segments. The π values are 0.092, 0.130, and 0.082% for East, Central, and West African chimpanzees, respectively, and 0.132% for all chimpanzees. These values are similar to or at most only 1.5 times higher than that for humans. The much larger difference in mtDNA diversity than in nuclear DNA diversity between humans and chimpanzees is puzzling. We speculate that it is due mainly to a reduction in effective population size (Ne) in the human lineage after the human-chimpanzee divergence, because a reduction in Ne has a stronger effect on mtDNA diversity than on nuclear DNA diversity.

Estimating time to onset of swine influenza symptoms after initial novel A(H1N1v) viral infection

2010 ◽  
Vol 139 (9) ◽  
pp. 1418-1424 ◽  
Author(s):  
B. D. M. TOM ◽  
A. J. VAN HOEK ◽  
R. PEBODY ◽  
J. McMENAMIN ◽  
C. ROBERTSON ◽  
...  
Keyword(s):  
Incubation Time ◽  
Time Distribution ◽  
Age Groups ◽  
Swine Influenza ◽  
Interval Censoring ◽  
Limited Data ◽  
History Of ◽  
Influenza Case ◽  
Time To Onset

SUMMARYCharacterization of the incubation time from infection to onset is important for understanding the natural history of infectious diseases. Attempts to estimate the incubation time distribution for novel A(H1N1v) have been, up to now, based on limited data or peculiar samples. We characterized this distribution for a generic group of symptomatic cases using laboratory-confirmed swine influenza case-information. Estimates of the incubation distribution for the pandemic influenza were derived through parametric time-to-event analyses of data on onset of symptoms and exposure dates, accounting for interval censoring. We estimated a mean of about 1·6–1·7 days with a standard deviation of 2 days for the incubation time distribution in those who became symptomatic after infection with the A(H1N1v) virus strain. Separate analyses for the <15 years and ⩾15 years age groups showed a significant (P<0·02) difference with a longer mean incubation time in the older age group.

scholarly journals The lower crustal Dasu Tonalite and its implications for the formation reformation-exhumation history of the Kohistan arc crust

2008 ◽  
Vol 2 (4) ◽  
pp. 211 ◽  
Author(s):  
Takashi Nakajima ◽  
IS Williams ◽  
H Hyodo ◽  
K Miyasaka ◽  
Y Kono ◽  
...  
Keyword(s):  
History Of ◽  
Lower Crustal ◽  
Exhumation History

Herbal Supplement PC-Spes for Prostate Cancer

2002 ◽  
Vol 36 (5) ◽  
pp. 921-926 ◽  
Author(s):  
Mário L de Lemos
Keyword(s):  
Prostate Cancer ◽  
Cancer Patients ◽  
Estrogenic Activity ◽  
Estrogen Therapy ◽  
Herbal Supplement ◽  
Limited Data ◽  
History Of ◽  
Abnormal Bleeding ◽  
Androgen Suppression ◽  
American Society

OBJECTIVE: To determine the efficacy and toxicity of the herbal supplement PC-Spes in prostate cancer patients. METHODS: Literature search through MEDLINE (1966–October 2001), PubMed, and abstracts from the Annual Meeting of the American Society of Clinical Oncology (1995–2001). RESULTS: PC-Spes was associated with biochemical and clinical response in some prostate cancer patients. The mechanisms of action of PC-Spes appeared to be related to its estrogenic activity. CONCLUSIONS: PC-Spes is associated with some efficacy in prostate cancer patients. Due to the limited data available, it should not be used to replace standard androgen suppression therapy in androgen-dependent patients. PC-Spes may have a role for patients who have failed standard treatments for androgen-independent disease and have no history of thromboembolism or abnormal bleeding. PC-Spes has a toxicity profile similar to those of androgen suppression and estrogen therapy.

The Archaeology of Medieval Nubian Kingdoms

2021 ◽  
pp. 828-846
Author(s):  
Artur Obłuski
Keyword(s):  
Church Architecture ◽  
Archaeological Research ◽  
Limited Data ◽  
Historical Sources ◽  
Settlement Systems ◽  
Dynamic Perspective ◽  
History Of ◽  
Medieval Nubia ◽  
Regional Perspective

The following chapter approaches the archaeology of medieval Nubia from a regional perspective. First, it presents the nomenclature used for chronology, then the history of archaeological research in Nubia determined by construction of dams on the Nile. The focus of the paper are the settlement systems of two medieval Nubian kingdoms: Nobadia and Makuria. Alwa is treated lightly due to the limited data. They are discussed in a static (settlement hierarchy) and dynamic perspective (integration of settlement systems in time). Church architecture as an indicator of regionalism is also debated. Some topics integrally associated with archaeology of Nubia like historical sources (Ruffini, this volume), languages (Łajtar and Ochała, this volume), capitals of the states (Żurawski, this volume), art and pottery (Zielińska, this volume) are generally absent here but are tackled by other authors in the same volume.

Conservation, Ecology, and Management of Catfish: The Second International Symposium

2011 ◽  
Keyword(s):  
Water Chemistry ◽  
Environmental History ◽  
Ictalurus Punctatus ◽  
Water Samples ◽  
Process Chemistry ◽  
Chemical Signatures ◽  
Spatial Differences ◽  
Pectoral Spine ◽  
History Of ◽  
Highly Correlated

<em>Abstract</em>.—Natural chemical markers in otoliths and fin rays have proven useful for retrospectively describing environmental history of fishes in a variety of environments. However, no studies have applied this technique to catfishes or evaluated catfish pectoral spine chemistry as a nonlethal alternative to otolith chemistry. We characterized relationships between water, otolith, and pectoral spine (articulating process) chemistry for channel catfish <em>Ictalurus punctatus</em>, flathead catfish <em>Pylodictis olivaris</em>, and blue catfish <em>I. furcatus</em> and determined the accuracy with which fish could be classified to their environment of capture using otolith and pectoral spine chemical signatures. Fish and water samples were collected from nine sites during 2009. Otolith, spine, and water samples were analyzed for Sr:Ca and Ba:Ca; otolith δ<sup>18</sup>O and δ<sup>13</sup>C and water δ<sup>18</sup>O were also measured. Water, otolith, and spine Sr:Ca were highly correlated, as were water and otolith δ<sup>18</sup>O. Relationships between water, otolith, and spine chemistry did not differ among species. Otolith Sr:Ca, δ<sup>18</sup>O, and δ<sup>13</sup>C and spine Sr:Ca differed among sites, reflecting geographic differences in water chemistry. Neither otolith nor spine Ba:Ca differed among sites despite intersite differences in water Ba:Ca. Both otolith Sr:Ca, δ<sup>18</sup>O, and δ<sup>13</sup>C and fin spine Sr:Ca classified fish to their environment of capture with a high degree of accuracy, except in the middle and lower Mississippi River where many recent immigrants appeared to be present. Natural chemical signatures in otoliths or pectoral spines will likely be effective for reconstructing environmental history of catfishes when spatial differences in water chemistry are present, enabling investigations of stock mixing and recruitment sources for these species.

scholarly journals Acute kidney injury as initial presentation of renal lymphoma: Diagnostic and therapeutic challenges in a resource-limited setting

2019 ◽  
Vol 7 ◽  
pp. 2050313X1984525 ◽  
Author(s):  
Jeannine Anyingu Aminde ◽  
Nkweta Eugene Adze ◽  
Guisilla Ankwatia Dedino ◽  
Leopold Ndemnge Aminde
Keyword(s):  
Acute Kidney Injury ◽  
State Of The Art ◽  
Renal Involvement ◽  
Kidney Injury ◽  
Abdominal Distension ◽  
Lymphoma Patient ◽  
Limited Data ◽  
Resource Limited ◽  
History Of ◽  
Limited Setting

Non-Hodgkin’s lymphoma is reportedly common in Africa; however, there is limited data on renal involvement. Acute kidney injury only at presentation is rare for lymphoproliferative malignancies. A 7-year old presented to our facility with a 2-week history of progressive abdominal distension and pain, examination revealed anasarca and hypertension. On further evaluation, there were bilateral nephromegaly, acute kidney injury (AKI) and cytomorphological findings suggestive of lymphoma. Patient management was mostly supportive, and evolution was unfavourable leading to his demise. We discuss diagnostic and therapeutic challenges due to unavailability of state-of-the-art facilities in resource-constrained settings.

Age, Growth, Food, and Yield of the White Sturgeon (Acipenser transmontanus) of the Fraser River, British Columbia

1968 ◽  
Vol 25 (12) ◽  
pp. 2589-2602 ◽  
Author(s):  
S. N. Semakula ◽  
P. A. Larkin
Keyword(s):  
Size Range ◽  
Age Distribution ◽  
White Sturgeon ◽  
Fraser River ◽  
Limited Data ◽  
Pectoral Fin ◽  
Sturgeon Species ◽  
Fin Ray ◽  
History Of ◽  
Back Calculation

For white sturgeon taken incidentally in the salmon gillnet fishery in the Fraser River during the summer of 1962, pectoral fin ray sections indicated that over three-quarters were fish aged 9–16 years. Gillnets for salmon apparently select sturgeon over a size range between 30 and 60 inches. Back-calculation of size attained at previous ages indicated that after attaining a length close to 20 inches by age 5, the sturgeon grow about 2 inches per year to about age 25. Limited data from pectoral fin ray sections suggest that age at first spawning is from 11 to 22 years for males, and from 11 to 34 for females. Subsequent spawning is apparently at intervals of 4–9 years. Fraser River sturgeon are more piscivorous than has been recorded for white sturgeon and other sturgeon species elsewhere, about one-half of the stomachs containing fish, especially eulachons. The age distribution in the catch, though biased by selection, was used to estimate rates of natural and fishing mortality. The eumetric fishing curve suggests that present yield could be increased by a greater size at first capture, particularly if the natural mortality rate is as low as 0.05. The history of the sturgeon fishery suggest that sustainable yield could exceed 100,000 lb per year. The commercial landings in recent years average 30,000–40,000 lb. The sport fishery may take an additional 20,000–30,000 lb. Sustained yield in the circumstances of the present fishery could be 80,000 lb per year, about 25% more than the present catch. Some recommendations are made for management, stressing the importance of protection of an annual spawning population of 300–600 females.

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