OLR(1980)27(12) C. Submarine Geology and Geophysics 873

of magmatic origin. Some of the chemical differ- ences noted were contents of titanium, aluminum, magnesium, alkaline elements and normative ratios. Geological Institute, U.S.S.R. Academy of Sciences, Moscow, U.S.S.R. (bas)

14. Oil and gas

80:5947 Kvenvolden, K. A., 1980. Organics yield clues

about oil in the deep sea. Geotimes, 25(7): 19- 20.

The shipboard and shore-based programs of the D.S.D.P., including sample storage provisions, are briefly described. Much of the work to date on deep-sea organics has been directed toward source rock petroleum potential. Anticipated development of the hydraulic piston corer, the pressure core barrel and a riser system for the Glomar Explorer should greatly increase our present knowledge of the sediment record, enable much deeper coring and drilling, and provide knowledge of gas hydrates (and therefore reserves). Includes a list of organic compounds in D.S.D.P. sediment samples. Chairman, JOIDES Advisory Panel on Organic Geochemistry, U.S. Geological Survey, Menlo Park, Calif. 94025, U.S.A. (slr)

15. Manganese nodules, etc .

80:5948 Girin, Yu. P., V. V. Gordeyev, Ye. G. Gurvich, V.

N. Lukashin, A. A. Migdisov and N. V. Barskaya, 1979. Chemical composition of Fe- Mn nodules from metall iferous and normal pelagic sediments of the southeast Pacific Ocean. Geochem. int. (a translation of Geokhimiya), 16(1): 45-61.

Chemical analyses of 72 surface and subsurface samples recovered from 18 southeast Pacific locations reveal a complex pattern of change in the concentration and composition of ore substance (free iron and manganese hydroxide) in Fe-Mn nodules. Hydrothermal activity affected nodule compositions by reducing hydrolysate mineral con- centrations. V. N. Vernadskiy Insti tute of Geochemistry and Analytical Chemistry, Academy of Sciences of the U.S.S.R. (kink)

t h r e e - s t a g e d i s s o l u t i o n - r e p l a c e m e n t mechanism.] C. r. hebd. Seanc. Acad. Sci., Paris, (D)290(13): 831-834.

Dissolution of calcareous plankton remains which settle in the deep-sea, replacement by an Fe-Si complex, evolution of Fe 3÷ oxides, and Mn ion catalysis by the Fe 3+ oxides constitute a mechanism for the origin of manganese coatings. Includes 6 micrographs. Geologie dynamique, Universite Pierre-et-Marie-Curie, Paris-VI,, 4, place Jussieu, 75230, Paris Cedex 05, France. (izs)

16. Local and regional tectonics, earthquakes and seismicity

80:5950 Acharya, H. K. and Y. P. Aggarwal, 1978/80.

Seismicity and tectonics of the Philippine Islands. J. geophys. Res., 85(B6): 3239-3250.

A study of seismicity, volcanic activity, and new fault plane solutions reveals the complex tectonic setting of the Philippine Islands which are flanked by opposing subduction zones. The Eurasian Plate thrusts eastward beneath the western Philippines (though subduction has stopped in regions of con- tinental crust) while the Philippine Sea Plate thrusts westward beneath the eastern islands. Fault plane solutions and field observations suggest that one component of movement between the two subduction zones is taken up by a left lateral transform Philippine Fault. Stone & Webster Engineering Corporation, Boston, Mass. 02107, U.S.A. (kmk)

80:5951 Biswas, N. N., L. Gedney and J. Agnew, 1980.

Seismicity of western Alaska. Bull. seism. Soc. Am., 70(3): 873-883.

Many of the epicenters of the 300 earthquakes of magnitudes ranging from 1.0 to 4.5 recorded by a local seismograph network during a two-year period, were found to be located in the vicinity of offshore and onshore traces of faults around the Seward Peninsula. 'The area appears to represent a separate tectonic province with associated seismicity of the intraplate type.' Geophysical Institute, University of Alaska, Fairbanks, Alaska 99701, U.S.A. (hbf)

80:5949 Nesteroff, W. D., 1980. Le depot des films de

manganese recouvrant les roches oceaniques: un mecanisme de formation en trois etapes. [Origin of deep-sea manganese coatings: a

80:5952 Drury, S. A. and R. W. Holt, 1980. The tectonic

f ramework of the South Indian Craton: a reconnaissance involving LANDSAT im- agery. Tectonophysics, 65(3/4): T1-T15.