OLR(1979)26(12) C. Submarine Geology and Geophysics 783

79:6025 Streckeisen, Albert, 1979. Classification and nomen-

clature of volcanic rocks, iamprophyres, carbona- tites, and melilitic rocks: recommendations and suggestions of the IUGS Subcommission on the Systematics of Igneous Rocks. Geology, 7(7): 331-335. IUGS Subcommission Mineralogisches Institut, Sahlistrasse, 6, Ch-3012, Bern, Switzer- land.

79:6026 Wyllie, P. J., 1979. Magmas and volatile components.

A m. Mineralogist, 64(5/6)" 469-500.

Effects of the abundant quantities of H 20 and CO2 in magmas are investigated. Phase diagrams for periodotite-CO2-H20 and basalt-andesite-rhyolite- H 20, determinations of the petrological structure of subduction zones and data on NaAISi30~-H20-HF are presented. Ca. 90 references. Department of Geophysical Sciences, University of Chicago, Chicago, Ill. 60637, U.S.A. (rio)

14. Oil and gas 79:6027

Arthur, M. A. and S. O. Schlanger, 1979. Cretaceous 'oceanic anoxic events' as causal factors in devel- opment of reef-reservoired giant oil fields. Am. Ass. Petrol. Geol. Bull., 63(6): 870-885.

Poor oceanic mixing resulting from stable density stratification helped preserve large amounts of organic carbon in Cretaceous basin, slope, and shelf facies. Rudist reef deposits, drowned in Cretaceous transgressions and scaled by fine-grained sediment, stratigraphically linked to black shale source beds, are likely reservoirs for oil and gas. Includes stratigraphic sections and ca. 100 references. Scripps Institution of Oceanography, La Jolla, Calif. 92093, U.S.A. (dme)

density fields, often located at the border of high organic productivity surficial zones, also evolve under the influence of benthic faunal activity. Includes I1 bottom photos and ca. 120 references, institut Oc~anographique, 195 rue Saint-Jacques, F 75005 Paris, France.

79:6029 Turekian, K. K., J. K. Cochran, S. Krishnaswami,

W. A. Lanford, P. D. Parker and K. A. Bauer. 1979. The measurement of '"Be in manganese nodules using a tandem Van de Graaff acceler- ator. Geophys. Res. Letts, 6(5): 41%420.

A 4.5 mm per m.y. growth rate was derived for a manganese nodule from the Rio Grande Ridge using a Be-10 profile. A possible relationship between the Be- 10 and Mn fluxes to nodules was identified. Department of Geology and Geophysics, Yale University, New Haven, Conn. 06520, U.S.A. (rio)

16. Local and regional tectonics, earth- quakes and seismicity

79:6030 Andon, Masataka and E. I. Balazs, 1979. Geodetic

evidence for aseismic subduction of the Juan de Fuca Plate, J. geophys. Res., 84(B6): 3023-3028.

A down-to-the-east crustal tilt rate across western Washington, disclosed by precise leveling over a 70- year period, suggests that the Juan de Fuca Plate is aseismically underthrusting the North American Plate. According to this hypothesis, the frequent occurrence of large thrust earthquakes that ordinarily accompany plate convergence need not be expected along the Juan de Fuca subduction zone. This conclusion is consistent with the fact that there have been no great earthquakes in western Washington in the past 140 years. Disaster Prevention Research Institute, Kyoto University, Uji, Kyoto 611, Japan.

15. Manganese nodules, etc. 79:6028

Dangeard, L. and J. R. Vanney, 1978. Environne- ment physiographique g~ologique et biologique des pavements profonds de nodules polymc~tal- liques. [Physiographic, geological and biological environment of deep-sea pavements of poly- metallic nodules.] Revue G~ogr. phys. G~ol. dynam., 20(5): 371-387.

Formation and distribution of the main polymetallic nodule pavements are controlled by several interrelated factors. Nine fields from three 'provinces' are described to show the role of the physiographic environment. The most common geological base is the lower part of a volcanic slope made of debris. High

79:6031 Bankwitz, Elfriede and Peter Bankwitz, 1978. Rift

activity in the eastern Pacific. Ver~ff Zentralinst. Phys. Erde, 46:45 pp.

The permanent rotation of the N.E. Pacific Rift during the last 80 m.y. is divided into 3 superordinate rotations which are further subdivided into rotations lasting about 10 m.y. All rotations are thought to be responses of the rift to changes in the spreading pole position. Rotation of the S.E. Pacific Rift during the last 7 m.y., hinge zones and pendulum movements related to magmatic activity of the rifts, and internal deformations of the Pacific and Juan de Fuca plates are also discussed. Figures include structural sections. Akademie der Wissenschaften der DDR, Zentralinstitut fiir Physik der Erde, Berlin, D.R.G. (rio)