Sedimentary facies of the Nova Scotian upper and middle continental slope, offshore eastern Canada

Sedimentary facies of the Nova Scotian upper and middle continental slope, offshore eastern Canada

866 D. SubmarineGeologyand Geophysics A program was conducted in the Santa Barbara Channel (offshore California) to ascertain a marine gradiometer's...

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866

D. SubmarineGeologyand Geophysics

A program was conducted in the Santa Barbara Channel (offshore California) to ascertain a marine gradiometer's ability 'to produce diurnal-free total magnetic intensity data.' For this location, 'shipminus-shore and integrated total intensities produced maps with standard residual misties of 0.55 and 0.62 gammas, respectively.' The marine magnetic gradiometer's operational simplicity and efficacy in eliminating diurnal activity support its routine use although 'moderately more sophisticated data analysis procedures' are required. ARCO Oil and Gas Co., P.O. Box 2819, Dallas, Tex. 75221, USA. (ihz) 84:6063 Ganeev, A.A., N.R. Mashianov, G.B. Sveshnikov and S.E. Sholupov, 1984. On the possibility of active tectonic structure mapping using mercury haloes over sea surfaces. Dokl. Akad. Nauk SSSR, 275(5):1162-1163. (In Russian.) 84:6064 Karcz, Iaakov, Zygmunt Perelman and Richard Panski, 1984. Assessment of the possible use of a Tellurometer MA 100 in the study of horizontal crustal movements along the Jordan-Dead Sea Rift. Israel J. Earth-Sci., 33(i/2):63-71. The calibration and reproducibility of measurements made with a Tellurometer MA 100 (Set. Nr. 508) electro-optical distance measuring instrument are discussed based on data collected from 1976-1983. The authors conclude that the instrument is suitable for measuring plate motions larger than 0.3 mm/yr, in particular along the Jordan-Dead Sea Rift, if a measurement program can be sustained for at least 20-30 years. Geol. Survey of Israel, 30 Malchei Israel St., Jerusalem 95 501 Israel. (amt) 84:6065 Turcotte, D.L. and P.M. Kenyon, 1984. Synthetic passive margin stratigraphy. Am. Ass. Petrol. Geol. Bull., 68(6):768-775. Synthetic stratigraphic cross sections are derived mathematically for a variety of simple conditions. Model variables include variations in sea level and rates of tectonic subsidence, sedimentation, and erosion. Derived stratigraphic relationships include unconformities, correlative conformities and disconformities, coastal onlap, coastal toplap, erosional truncation, pinch-out, and sigrnoidal progradational clinoforms. An important conclusion is that the rate of erosion is a dominant variable in determining the type of stratigraphic section observed. The proposed approach may provide the basis for either a forward or inverse modelling of seismic stratigraphic sec-

OLR (1984)31(12)

tions. Dept. of Geol. Sci., Cornell Univ., Ithaca, NY 14853, USA. 84:6066 Wellstood, Frederick, C. Heiden and John Clarke, 1984. Integrated dc SQUID (superconducting quantum interference device) magnetometer with a high slew rate. Rev. scient. Instrums, 55(6):952957. Dept. of Phys., Univ. of Calif., Berkeley, Calif. 94720, USA. 84:6067 Wilson, G.C., A.E. Litherland and J.C. Rucklidge, 1984. Dating of sediments using accelerator mass spectrometry. Chem. Geol., 44(1/3):1-17. Assessed are the current status and future prospects for dating recent sediments by direct counting of radionuclides (cosmogenic, natural terrestrial, and artificial) using accelerator-based mass spectrometers. Relevant isotopes and equipment are discussed, with particular reference to the 3-MV electrostatic accelerator system of the University of Toronto. Inherent difficulties of the new method are outlined; possible applications are identified. The ability to obtain radiocarbon dates from very small samples (e.g., ~<100 /zg C) illustrates the promise of the method. ISOTRACE Lab., Univ. of Toronto, Toronto, Ont. M5S 1A7, Canada.

D40. Area studies, surveys, bathymetry 84:6068 Aljinovi~, Bruno, Ivan Blaskovi~, Dragutin Cvijanovi6, Eduard Prelogovi~, Dragutin Skoko and Nusret Brdarevi6, 1984. Correlation of geophysical, geological and seismological data in the coastal part of Yugoslavia. Boll. Oceanol. teor. appl., II(2):77-90. Geofizika, Zagreb, Yugoslavia. 84:6069 Feng, Yun, Yongqi Zhu and Chengkai Zeng, 1983. Compilation and design of the topographic maps of the Talwan Strait. Taiwan Strait, 2(2):56-65. (In Chinese, English abstract.) The list includes a comprehensive tabulation of existing maps and written data on the Taiwan Strait with notations on water depths, topographic characteristics, and cartographic techniques. Second Inst. of Oceanogr., Natl. Bureau of Oceanography, People's Republic of China. (hbf) 84:6070 Hill, P.R., 1984. Sedimentary facies of the Nova Scotian upper and middle continental slope,

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D. Submarine Geology and Geophysics

offshore eastern Canada. Sedimentology, 31(3): 293-309. Bedford Inst. of Oceanogr., P.O. Box 1006, Dartmouth, NS B2Y 4A2, Canada.

84:6071 Johnson, D.P. and D.E. Searle, 1984. Post-glacial seismic stratigraphy, central Great Barrier Reef, Australia. Sedimentology, 31(3):335-352. Dept. of Geol., James Cook Univ., Townsville, Queensland 4811, Australia. 84:6072 Siddiquie, H.N., G.C. Bhattacharya, M.C. Pathak and S.Z. Qasim, 1983. Indira Mount--an underwater mountain in the Antarctic Ocean. In:

Scientific Report of First Indian Expedition to Antarctica. Technical Publication No. 1; De-

867

the Astrid Ridge, Dronning Maud Land, Antarctica. In: Scientific Report of First Indian Expedition to Antarctica. Technical Publication No. 1; Department of Ocean Development, New Delhi, India; pp. 166-181. Echosounding, seismic profiling and magnetic data are presented. Astrid Ridge rises from ~4000 m to 1000 m on the continental margin of Dronning Maud Land. To the south the crest is flat but to the north it is marked by a 240-380 m deep valley. The western flanks are gently sloping; the eastern flanks are marked by steep scarps. The magnetic data indicate a depth to basement of 3.0 to 3.4 km and are used to discriminate between surficial and deep crustal effects. Natl. Inst. of Oceanogr., Dona Paula, Goa 403 004, India. (amt)

partment of Ocean Development, New Delhi, India; pp. 161-165. A major topographic high was located at 53°39.79"S, 47°55.82"E at a depth of 4500 m and designated 'Indira Mount.' The mount is approximately 3300 m high; one of its many peaks rises to within 880 m of the surface. The multiple peaks and high magnetic anomalies suggest a volcanic origin with perhaps more than one active episode. Natl. Inst. of Oceanogr., Dona Paula, Goa 403 004, India. (msg)

84:6073 Siddiquie, H.N. and M.C. Pathak, 1983. Bathymetry and geomorphology of the approaches to Dakshin Gangoaq, Princess Astrid coast, Queen Maud Land, Antarctica. In: Scientific Report of First Indian Expedition to Antarctica. Technical Publication No. 1; Department of Ocean Development, New Delhi, India; pp. 149-152. Depths along the route of the First Indian Expedition ranged from 740 m at the northern edge of the ice pack to 224 m at the ice shelf. The route is safe for navigation except for the presence of seasonal ice cover and large semi-permanent icebergs. A sill at about 120 m depth separates the deeper open ocean (>700 m) to the north from 200-700 m depths to the south. The position of the sill is marked by the grounding of numerous icebergs. The sill may play a significant role in the separation of water masses and in the development of polynyas. Natl. Inst. of Oceanogr., Dona Paula, Goa 403 004, India.

D70. Coasts, beaches, marshes 84:6075 Dalrymple, R.W., 1984. Morphology and internal structure of sandwaves in the Bay of Fundy. Sedimentology, 31(3):365-382. Dept. of Geol. Sci., Queen's Univ., Kingston, Ont. K7L 3N6, Canada.

D$0. Reefs and atolls 84:6076 Aharon, Paul and H.H. Veeh, 1984. Isotope studies of insular phosphates explain atoll phosphatization. Nature, Land., 309(5969):614-617. Coral atoll carbonate apatite is thought to be the result of chemical interaction between solutions leaching seabird guano and the underlying reef limestone. Presented here are oxygen and carbon isotope data from carbonate apatites which elucidate the process of atoll phosphogenesis and the palaeoclimatic conditions in which it occurs. Apparently there were drier climates in the tropics during the ice ages, associated with an extension of equatorial upwelling in the Pacific. Dept. of Geol., Louisiana State Univ., Baton Rouge, La. 70803, USA.

84:6077 Potts, D.C., 1984. Generation times and the Qua-

ternary evolution of reef-building corals. Paleobiology, 10(1):48-58.

DS0. Subsurface structure 84:6074 Siddiquie, H.N., D.G. Rao and M.V. Ramana, 1983.

A geomorphologic, seismic and magnetic study of

It is proposed that Pliocene-Quaternary sea level fluctuations created unstable environments for Indo-Pacific shallow-water corals resulting in faunal stasis for species with long generation times. For