Geochemistry in the Uchi subprovince, northern Superior Province : an evaluation of the geodynamic evolution of the northern margin of the Superior Province ocean basin

Older assemblages of the Uchi subprovince, northern Superior Province, Canada, ranging in age from 2.9 to 3.0 Ga, are dominated by an association of komatiite-tholeiite sequences intercalated with felsic volcanic rocks. Komatiites vary from weakly LREE enriched to strongly depleted. The majority of ultramafic rocks display the conjunction of negative Nb anomalies with trends of increasing SiO2 and La/Smn, indicative of contamination by a felsic component. Many of the komatiites and komatiitic basalts are characterised by high V/Yb and Sc/Yb ratios which are unique amongst Archean komatiites. Tholeiitic flows intercalated with the komatiites typically display flat REE patterns with variable Nb anomalies, consistent with minor degrees of contamination. Two suites of felsic volcanic rocks are intercalated with the komatiite-tholeiite sequences of the older assemblages. Both types display pronounced LREE enrichment and negative Nb and Ti anomalies, but Type 1 has strongly fractionated HREE patterns, whereas Type 2 HREE are generally flat in conjunction with elevated compatible element contents. Collectively, the geochemical, geochronological and stratigraphic evidence from the northern Superior Province greenstone belts provide evidence for both a spatial and temporal association of mantle plumes and subduction zones during generation of the proto-continent nucleus to the Superior Province. The 2.8-2.9 Ga assemblages of the Uchi subprovince comprise mafic tholeiites characterised by predominantly flat REE, along with volumetrically significant units of felsic to intermediate volcanic rocks, that display enriched LREE and moderately fractionated HREE in conjunction with pronounced negative Nb anomalies. The geochemistry and geochronology of these assemblages is consistent with the formation of ocean plateau fragments which were accreted to the Uchi paleo continental margin where they subsequently formed the basement for a subduction related arc complex. Five distinct suites have been recognised in the ~2.7 Ga Confederation assemblage: (1) tholeiitic basalts with flat to smoothly depleted REE; (2) tholeiites with flat to weakly depleted LREE in conjunction with pronounced negative Nb anomalies; (3) Fe-rich basalts with elevated Ti and P contents, enriched LREE and fractionated HREE; (4) LREE enriched basalts and andesites with negative Nb anomalies; and (5) dacites and rhyolites with variably enriched LREE, moderately fractionated HREE and variable HFSE anomalies. The occurrence of this varied range of rocks in a single assemblage is comparable to modern back arc basins

CORRELATIONS BETWEEN TRUNK AND BAT KINEMATICS FOR BASEBALL PLAYERS CALCULATED USING BOTH INDIVIDUAL AND GROUP STATISTICS

This study aimed to investigate kinematic parameters associated with high batting velocity by using both group and individual analysis methods. Twenty seven junior baseball players each performed 35 strikes off a tee at speeds of 60, 80 and 100% of maximum; with pelvis, upper-trunk and bat kinematics measured by 3D motion analysis. The maximum values of all kinematic variables were positively associated with bat speed when assessed with both group and individual methods. For variables measured at impact, however, there were very different individual associations; with some participants showing strong positive correlations and others having similarly strong negative correlations with bat speed. These findings indicate that different players use different techniques to achieve high bat speeds

Anthropometric and physiological factors affecting batted ball speed of adolescent baseball players

Fifty-seven junior baseball players performed eight swings off a tee to record ball exit speed, as well as tests of grip strength, standing broad jump, lateral-to-medial (LM) jumps, chin-ups and chest pass with a medicine ball. The height, weight and age of each participant was also recorded. All anthropometric and physiological tests were significantly positively correlated with ball speed (p \u3c 0.05). Collinearity between variables meant that only chest pass (R² = 0.70, p = 0.000), body mass (ΔR² = 0.03, Δp = 0.021) and LM jump (ΔR² = 0.04, Δp = 0.005) made independent contributions to a stepwise linear regression. These findings corroborate the expectation that upper body power is a major determinant of batting speed, with leg power adding an additional, independent contribution to performance

Studies on the microbiology of a soil chronosequence near the Franz Josef Glacier : A thesis submitted in partial fulfilment of the requirements for the degree of Master of Science with Honours in the University of Canterbury

It has been the aim of the present study to investigate the changes, both qualitative and quantitative, that have taken place in a soil bacterial population from the time of an uncolonized parent material, through a small number of steps that represent the initial and early stages in the formation of a soil

The effects of debt indexation on the value of the firm

Thesis: M.S., Massachusetts Institute of Technology, Sloan School of Management, 1975Bibliography: leaves 86-87.by Peter F. Hollings and George Raff.M.S.M.S. Massachusetts Institute of Technology, Sloan School of Managemen

The role of porphyry-related skarns in the Chating porphyry copper and gold deposit, eastern China

The Chating deposit is a porphyry copper deposit in the Middle Lower Yangtze River Valley Metallogenic Belt, with skarns found in both the carbonate wall rock and in carbonate xenoliths in the intrusions. Detailed drill hole logging identified endoskarn and exoskarn in Chating, mainly distributed inside the ore–bearing quartz diorite porphyry instead of at the contact with the country rock. The skarns at Chating are unmineralized unless overprinted by porphyry related copper mineralization. Garnet in the Chating skarns can be divided into several types based on their occurrence and whether they were overprinted by porphyry mineralization. The garnets from the ore–bearing (G1a), barren endoskarn (G1b) and proximal ore–bearing exoskarn (G2a) are LREE-enriched, HREE–depleted with positive Eu anomalies whereas garnets from the barren massive exoskarn (G2b) are LREE-enriched with flat HREE and negative Eu anomalies. The G3 garnets are from marbleized skarn distal to the ore-bearing quartz diorite porphyry and consist of Al-rich and Fe-rich andradite; the Al–rich G3 garnets are LREE-depleted and HREE-enriched whereas the Fe-rich G3 garnets are LREE-enriched and HREE-depleted, both have negative Eu anomalies. The physicochemical conditions and composition of skarn-forming fluids controlled the REE, Eu, U and Y distribution in the garnets. The similarities of the REE patterns to those of magmatic–derived fluids suggests a dominantly magmatic fluid formed the endoskarn and proximal exoskarn. Fluid–rock interaction and addition of external fluids diluted the fluid that formed the exoskarn, decreasing the Cl and metal contents, resulting in lower REE contents and negative Eu anomalies in G2b and G3 garnets. The δ S data for anhydrite from potassic alteration, sericite alteration, endoskarn and exoskarn range from 3.51‰ to 10.92‰, consistent with a dominantly magmatic fluid source. The δ S for the anhydrite from the skarns ranges from 3.51‰ to 8.74‰, which combined with the absence of coeval sulfides, suggests a very high oxygen fugacity for the skarn-forming fluids. The small-scale skarns in Chating contain more anhydrite than garnet and consequently did not act as ground preparation as they do in typical skarn deposits. We propose that the anhydrite-rich exoskarn and the small scale of the endoskarn, combined with the high oxygen fugacity and low Cl content in the skarn-forming fluids resulted in the barren skarns of the Chating deposit. 34 34This work was financially supported by the National Key Research and Development Program of China (2016YFC0600206), the Natural Science Foundation of China (grants 41320104003, 91962218), the Fundamental Research Funds for the Central Universities of China (grants PA2019GDZC0093) and the China Scholarship Council (CSC) (201906690031), the National Natural Science Foundation of China (grant no. 41702071), and the Academic newcomer promotion plan B of Hefei University of technology (JZ2019HGTB0070)

Magma generation and sulfide saturation of Permian mafic-ultramafic intrusions from the western part of the Northern Tianshan in NW China: implications for Ni-Cu mineralization

Compared to Permian magmatic Ni-Cu sulfide deposits in the eastern part of the Northern Tianshan, such as Huangshan and Huangshandong, those in the western part (e.g., Baixintan and Lubei) are poorly documented. Zircon ID-TIMS U-Pb age data (279.7 ± 0.2 Ma) of lherzolite and LA-ICPMS U-Pb age data (277.8 ± 3.4 Ma) of a hornblende gabbro suggest the Lubei intrusion was emplaced in the Early Permian. The Baixintan and Lubei mafic-ultramafic intrusive rocks are characterized by enrichments of large ion lithophile elements and Th and U relative to the high field strength elements, as well as depletion of Nb and Ta relative to mid-ocean ridge basalt. The (87Sr/86Sr)t (0.70354–0.70713), εNd(t) (2.80 to + 7.05), and εHf(t) (2.50–18.4) values for the intrusions indicate that they have assimilated Tianshan basement rocks, whereas the Se/S ratios (181 × 10−6 –418 × 10−6 ) and δ34SCDT values (− 0.13‰ to 0.90‰) of the sulfides suggest that crustal sulfur has not been incorporated into the magma. The decrease in Pd/Zr with increasing (Th/Nb)PM indicates that sulfide saturation accompanied crustal contamination. The olivine compositions and whole-rock chalcophile elements of the Baixintan and Lubei intrusions imply that the parental magma of the intrusive rocks in the west contains higher chalcophile elements than those in the east, which suggests that the mafic-ultramafic intrusions in the western part of the Northern Tianshan should be regarded as favorable Ni-Cu sulfide exploration targets.This work was supported by the National Natural Science Foundation of China (Grant Nos. U1803113, 41672069, 41630316, 41303031, and 41820104007), the China Academy of Science BLight of West China^ Program, and the Fundamental Research Funds for the Central Universities (JZ2018HGTB0246)