SOPAC region of the central and southwestern tropical Pacific

OLR(1984)31 (12)

D. SubmarineGeologyand Geophysics

84:6162 Tr~hu, A.M., 1984. Lateral velocity variations in the Omzco Transform Fault inferred from observed incident angles and azimuths of P-waves. Geophys. Jl R. astr. Soc., 77(3):711-728. Observed deflections of incident angles and azimuths of body waves from earthquakes and explosive shots in the Orozco Transform Fault are interpreted to reflect regional lateral velocity variations. Possible models are examined by 3-D ray tracing and suggest the presence of a low velocity zone (a magma chamber?) within the central transform region. 'Although these data alone do not provide irrefutable evidence for a magma chamber...the corrections to fault plane solutions and hypocenters implied by this model can explain major inconsistencies in the source parameters calculated relative to a laterally homogeneous velocity model.' USGS, Woods Hole, Mass. 02543, USA. (amt)

geology (see also D330Oil and gas, D340-Manganese nodules)

D320. Economic

84:6163

Chivas, A.R., J.R. O'Neil and George Katchan, 1984. Uplift and submarine formation of some Melanesian porphyry copper deposits: stable isotope evidence. Earth planet. Sci. Letts, 68(2): 326-334. Res. Sch. of Earth Sci., The Australian Nail. Univ., G.P.O. Box 4, Canberra ACT 2601, Australia.

D330. Oil and gas

881 84:6165

Kou, Caixiu, 1984. The pre--Oligocene in Zhujlang River mouth basin: a new oH prospect in the northern South China Sea. Mar. Geol. Quat. Geol., 4(2):41-47. (In Chinese, English abstract.)

D340. Manganese nodules, etc. 84:6166

Baturin, G.N., E.I. Fisher and V.L. Fisher, 1984. On the gold content in h'on-manganese nodules of the ocean. Dokl. Akad. Nauk SSSR, 275(2):421-424. (In Russian.) 84:6167

Cronan, D.S., 1984. Criteria for the recognition of areas of potentially economic manganese nodules and encrnstations in the CCOP/SOPAC region of the central and southwestern tropical Pacific. S. Pacif. mar. geol. Notes, U.N, Suva, 3(1):17pp. Criteria governing the location of manganese nodules of potential economic value--elevated biological productivity, depth near or below the CCD, and absence of turbidite sedimentation--indicate that nodules may be present in the southeastern and western East Central Pacific Basin, the eastern West Central Pacific Basin, and the North Penrhyn Basin. The occurrence and distribution of Co-rich crusts are probably determined by depth through the influence of the dissolved oxygen minimum zone. The deposits might be expected on seamount and island chains above 2000 m and north of 15° S. Appl. Geochem. Res. Gr., Dept. of Geol., Imperial Coll., London SW7, UK. 84:6168

84:6164

Chen, Yiheng, 1984. A preliminary analysis of hydrocarbon potential of the South Yellow Sea. Mar. Geol. Quat. Geol., 4(2):49-56. (In Chinese, English abstract.) Four stages of tectonic development are recognized in the evolution of the South Yellow Sea: a Sinian-Triassic platform stage; a Late Triassic-Late Cretaceous tectonic and igneous stage; a latest Cretaceous-Early Tertiary extension stage; and a Late Tertiary-Quaternary stage of subsidence and 'smooth' compression. Both the platform and continental facies of the first and last stages may contain hydrocarbons. (hbf)

Iushko-Z~akharova, O.E., V.E. Zakharov, M.S. Golovina, L.S. Dubakina and D.K. Shcherbachev, 1984. Native metals in ferromanganese nodules of the World Ocean. Dokl. Akad. Nauk S$$R, 275(2):465-467. (In Russian.)

84:6169

Marchig, V. and J.L. Reyss, 1984. Dlagonetie mobilization of manganese in Peru Basin se~lmerits, Geochim. cosmochim. Acta, 48(6):13491352. Mn contents and sedimentation rates of two cores from different areas of the Peru Basin have been determined. The southern core is associated with Mn