The age and distribution of the igneous rocks of Macquarie Island

Basalts associated with the formation of the Macquarie Ridge have been radiometrically dated at between 9.7 Ma and 11.5 Ma, giving a Middle Miocene age in approximate agreement with the age indicated by fossils in intercalated sedimentary rocks but younger than suggested by the nearby sea-floor spreading anomaly pattern

Al-rich spinel in primitive arc volcanics

Al-rich spinels (100Cr/(Cr + Al) 50 wt%) are common in alpine peridotites, both terrestrial and lunar mafic and ultramafic cumulates, and in certain metamorphic rocks, but they are apparently rare in terrestrial volcanic rocks. Here we describe the occurrence of Al-rich spinel inclusions in olivine phenocrysts in island are volcanic rocks from five new localities: Bukit Mapas (Sumatra) and eastern Ball in the Sunda are, and Epi, Merelava, and Ambrym islands in the Vanuatu are. More commonly, relatively Cr-rich spinels also occur as inclusions in the same olivine phenocrysts, and it appears that the Cr-poor aluminous spinels must be in disequilibrium with the host basaltic melts. In the rocks studied, Al-rich spinels also coexist with trapped silicate glasses and highly aluminous clinopyroxene in melt inclusions in olivine. This paragenesis suggests an origin involving contamination by localised Al-rich melt pockets as opposed to a xenocrystic origin. Two mechanisms to produce this high-Al melt in basaltic magma chambers are suggested: (1) localized high-Al melt production by complete breakdown of assimilated lower crustal gabbroic rocks. In this model the high-Al melt may crystallise Al-rich spinels which are subsequently trapped as solid inclusions by phenocryst phases of the host basaltic melt or may be trapped as melt inclusions in which Al-rich spinels and Al-rich clinopyroxene crystallise as daughter phases, and (2) incongruent breakdown of amphibole in amphibole-rich cumulates in sub-are, or sub-GIB volcano magma chambers. The latter reaction produces a melt with similar to 20-22% of Al2O3, aluminous clinopyroxene, Al-rich spinel and olivine. Mixing between these amphibole breakdown products and host basaltic melt may occur throughout the evolution of a magmatic system, but particularly during recharge with hot magnesian basalt batches. Aluminous spinels and aluminous clinopyroxene produced during amphibole breakdown, or perhaps crystallised from aluminous melt produced in the same reaction, are incorporated into the magma during recharge, and subsequently trapped, together with the coexisting Cr-spinels, by crystallising olivine and clinopyroxene

Effects of yoga - pranayama practices on metabolic parameters and anthropometry in type 2 diabetes

India being the diabetic capital of the world, there is a rise in the incidence of type 2 diabetes with the increase in age, physical inactivity and sedentary lifestyle. So, the present study was undertaken to assess the strength of association of these factors and the effects of yoga-pranayama in type 2 diabetes. We selected 44 uncomplicated type 2 diabetic patients in the age group of 40-55 years with diabetes duration of 1-10 years. They were divided into test group and control groups with 22 patients in each group. The test group (T1 and T2) were taught yoga and pranayama for 3 continuous months, 1 hour every day in the morning by yoga expert. The results showed significant decrease in  metabolic parameters, with p < 0.001 in FBS of both the T1 and T2 sub groups [T1- 182.87 + 45.55  to 135.77 + 38.88, T 2 – 160.64 + 41.22 to 130.82 + 36.11], PPBS with p< 0.001 [ T1- 270.64  + 76.6 to  196.90 + 64.67, T 2 – 230.62 + 71.32 to 183.46 + 52.20], Hb A 1c with p < 0.001 in  both the T1 and T2 sub groups, [T1- 9.77 + 0.5 % to  7.68 + 0.4% and T 2 – 8.46 + 0.3% to 7.23 + 0.3%]. There was significant decrease with p < 0.001 in triglycerides of both the T1 and T2 sub groups, [T1- 170 + 70.55 to 132.2 + 60.6, T 2 – 164 + 80.66 to 1143.1 + 28.89]. There was significant decrease with p < 0.001 in LDL of both the T1 and T2 sub groups [T1- 108 + 36.24to 98 + 33.2, T 2 – 101.28 + 32.34 to 86.21 + 27.2]. However, no significant change in HDL levels in test groups (T1 and T2). It also showed significant decrease in weight, BMI and waist- hip ratio in test group. Addition to above benefits there was significant decrease in the requirement of insulin per day in the T2, from 36.42 + 4.2 units to 31.48 + 3.2 units. There were no significant changes in the control group. Thereby concluding that, there are significant benefits of yoga- pranayama practices on metabolic parameters and anthropometric measurements in uncomplicated type 2 diabetes

Crustal assimilation versus subducted sediment input in west Sunda arc volcanics: an evaluation

New geochemical and Sr, Nd, and Pb isotopic analyses of Quaternary to Cretaceous sediments from the northeastern Indian Ocean are used to estimate the composition of the sedimentary material subducted along the Sunda Trench, and to evaluate the effects of crustal contamination versus subducted sediment input in the Quaternary volcanics of the west Sunda arc. Two sediment endmember components are identified: siliceous-clastic (SS) and calcareous-organogenic (CS); the latter can be regarded as SS strongly diluted by organogenic material, mainly CaCO. Siliceous-clastic sediments are characterised by a component isotopically and geochemically similar to "typical" average upper crust. Consequently, LILE and LREE concentrations, LILE/LILE and LILE/LREE values, and Sr, Nd, and Pb isotopic ratios in West Sunda arc volcanics cannot easily distinguish between assimilation of crustal material by uprising magmas and contamination of their mantle source by bulk sediments. Post-Miocene siliceous-clastic sediments sampled in the vicinity of the Sunda arc are largely derived from the arc itself, and therefore should not be used to evaluate the extent of sediment contamination of Indonesian arc volcanics. In addition, geophysical evidence suggests that post-Miocene sediments are largely accreted rather than subducted, and existing Be isotopic data imply that post-Miocene sediments are not recycled by present-day volcanism. As the least contaminated arc volcanics occur in the eastern section of the west Sunda arc, where the highest sediment fluxes have been calculated, subduction of pre-Miocene northeastern Indian Ocean sediments or incorporation of fluids released from them into the sources of west Sunda arc volcanics seem unable to reproduce the range and spatial distribution of Sr, Nd, and Pb isotopic values in the arc volcanics. By contrast assimilation of crustal material by uprising melts derived from Indian Ocean-type mantle wedge, up to a maximum of approximately 10% for the most contaminated arc volcanics, seems better able to account for the Sr, Nd, and Pb isotope systematics of the arc volcanics, and is consistent with the variations in crustal thickness and composition along the arc, and with the spatial distribution of Sr, Nd, and Pb isotope values in mafic arc volcanics. These conclusions are also supported by the low Be coupled with high B/Be values, and by the positive B/Be-SiO and B/Be-Sr/Sr correlations in calc-alkaline Sunda arc volcanics

Crustal contamination processes traced by helium isotopes: Examples from the Sunda arc, Indonesia

Helium isotope data have been obtained on well-characterised olivine and clinopyroxene phenocrysts and xenocrysts from thirteen volcanic centres located between central Sumatra and Sumbawa in the Sunda arc of Indonesia. Olivine crystals in mantle xenoliths (lherzolite) from Bukit Telor basalts are primitive (Mg# = 90), and their 3He 4He value ( R RA = 8.8) indicates that the Sumatran mantle wedge is MORB-like in helium isotope composition. All other samples have lower 3He 4He ratios ranging from 8.5RA to 4.5RA, with most (thirteen out of eighteen) following a trend of more radiogenic 3He 4He values with decreasing Mg#. The only exceptions to this trend are phenocrysts from Batur, Agung and Kerinci, which have MORB-like 3He 4He values but relatively low Mg# (Mg# = 70-71), and two highly inclusion-rich clinopyroxenes which have 3He 4He values lower than other samples of similar Mg#. The results indicate that crustal contamination unrelated to subduction in the Sunda arc is clearly recorded in the 3He 4He characteristics of mafic phenocrysts of subaerial volcanics, and that addition of radiogenic helium is related to low-pressure differentiation processes affecting the melts prior to eruption. These conclusions may have widespread applicability and indicate that helium isotope variations can act as an extremely sensitive tracer of upper crustal contamination