Whole rock analytical techniques and glas analytical techniques of silicic magmas from the South East Rift, Manus Basin

There has been much recent interest in the origin of silicic magmas at spreading centres away from any possible influence of continental crust. Here we present major and trace element data for 29 glasses (and 55 whole-rocks) sampled from a 40 km segment of the South East Rift in the Manus Basin that span the full compositional continuum from basalt to rhyolite (50-75 wt % SiO2). The glass data are accompanied by Sr-Nd-Pb, O and U-Th-Ra isotope data for selected samples. These overlap the ranges for published data from this part of the Manus Basin. Limited increases in Cl/K ratios with increasing SiO2, La-SiO2 and Yb-SiO2 relationships, and the oxygen isotope data rule out models in which the more silicic lavas result from partial melting of altered oceanic crust or altered oceanic gabbros. Rather, the data form a coherent array that is suggestive of closed-system fractional crystallization and this is well simulated by MELTS models run at 0.2 GPa and QFM (quartz-fayalite-magnetite buffer) with 1 wt % H2O, using a parental magma chosen from the basaltic glasses. Although some assimilation of altered oceanic crust or gabbro cannot be completely ruled out, there is no evidence that this plays an important role in the origin of the silicic lavas. The U-series disequilibria are dominated by 238U and 226Ra excesses that limit the timescale of differentiation to less than a few millennia. Overall, the data point to rapid evolution in relatively small magma lenses located near the base of thick oceanic crust; we speculate that this was coupled with relatively low rates of basaltic recharge. A similar model may be applicable to the generation of silicic magmas elsewhere in the ocean basins.

Concepts and techniques of machine safeguarding.

Shipping list no.: 92-486-P.

Principles and techniques of drug recognition expert training. The DRE Instructor Training School teacher-trainer manual.

National Highway Traffic Safety Administration, Washington, D.C.

Principles and techniques of drug recognition expert training. The DRE Instructor Training School student-instructor manual.

National Highway Traffic Safety Administration, Washington, D.C.

Techniques of dairy plant testing.

Includes bibliography.

Techniques of public health entomology,

Mode of access: Internet.

Photo interpretation of the terrain along the southern part of the Alaska Highway : An application of the combined knowledge and techniques of botany and geology to the phot interpretation of terrain in northern regions /

Folded plates, maps, and table in pocket.

Gourmet's basic French cookbook; techniques of French cuisine.

Mode of access: Internet.

PERT fundamentals; the fundamental concepts and techniques of PERT presented in a programed instruction format.

v. 1. Networking.- v. 2. Scheduling and planning.- v. 3. Workbook.

Techniques of law enforcement in the use of policewomen with special reference to social protection.

"A manual for the use of policewomen in the performance of their preventive-protective functions, and for the assistance of law enforcement administrators in the selection, assignment and most effective use of women police officers."

Techniques of preparing major BLS statistical series

Mode of access: Internet.

Techniques of observing the weather.

Bibliography: p. 197-205.

Techniques of population analysis.

Mode of access: Internet.

Techniques of fishpond management /

"Issued November 1943."