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Late Cretaceous-Cenozoic development of outer continental margin, southwestern Nova Scotia
OLR 1,1987)34 (12)
D. Submarine Geology and Geophysics
87:6895 Spanier, Ehud, 1987. A fossil record of shell boring: possible evidence for sea levd changes in the Red Sea. Estuar. coast. Shelf Sci., 24(6):873-879.
An aggregation of fossil shells of the Indo-Pacific muricid snails Chicoreus ramosus was found at a site 7 m above present mean sea level. Radiocarbon dating indicated an age of 1570-+80 yrBP. Some shells had bore-drilled holes, most uncompleted. Such holes were probably drilled by conspecifics in the absence of alternative food after disconnection from the sea. Since there is no evidence of human activity in this part of Tiran, such conditions could be caused only by a physical process that changed the relative water level. The character of the drilled holes and short period in which muricids maintain reproductive aggregates indicate a relatively rapid physical process. Dept. of Maritime Civilizations, Univ. of Haifa, Mount Carmel, Haifa 31999, Israel. 87:6896 Stea, R.R. and D.M. Wightman, 1987. Age of the Five Islands Formation, Nova Scotia, and the deglaclation of the Bay of Fundy. Quat. Res., 27(3):21 !-219.
Atomic mass spectrometry dating of shell material from the bottomset glaciomarine deltaic beds at Spencers Island, which are part of the previously undated Five Islands Formation, yields three ages between 14,300 and 12,600 yrBP, the first direct measurements for the time of deglaciation at the head of the Bay of Fundy. These dates are supported by similar radiocarbon dates obtained on ice margin glaciomarine deposits near St. John (New Brunswick) and imply that the bay became ice free about 14,000 yrBP. Nova Scotia Dept. of Mines and Energy, P.O. Box 1087, Halifax, NS, B3J 2XI, Canada. (hbf) 87:6897 Swift, S.A., 1987. Late Cretacemm-~nozoic development of outer continental m-rgin, southwestern Nova Scotia. Am. Ass. Petrol. Geol. Bull~ 71(6): 678-701.
Seismic stratigraphy and well data show that sediment accumulation was broadly controlled by sea level changes, although changes in sediment supply, morphology, current erosion, and salt tectonics were also significant. A Jurassic-Early Cretaceous carbonate platform controlled the location and steepness of the paleoslope until the Late Miocene, and local erosion of the outer shelf and slope in the Late Paleocene-Early Eocene produced chalky fans on the upper rise. Seaward extensions of Tertiary shelf-edge canyons are poorly defined
1053
except for the Eocene fans. Current eroded unconformities are common, but the only current deposit is a Pliocene interval restricted to the lowermost rise. Pleistocene turbidity currents have caused further erosion. WHOI, Woods Hole, MA 02543, USA. 87:6898 Traverse, Alfred, 1987. Pollen and spores date origin of rift basins from Texas to Nova Scotia as Early Late Triassic. Science, 236(4807):1469-1472. Dept. of Geosci., Pennsylvania State Univ., University Park, PA 16802, USA. 87:6899 Troelstra, S.R., 1987. Late Quaternary sedimentation in the Tyro and Kretheus basins, s o n t h n a of Crete. Mar. Geol~ 75(1-4):77-91. Geomar. Center Amsterdam, Free Univ., P.O. Box 7161, 1007 MC Amsterdam, Netherlands. 87:6900 Wilde, Pat, 1987. Model of progressive ventilation of the Late Preeambrhm-Early Paleozoic ocean. Am. J. Sci., 287(5):442-459.
A quantitative adveetion-diffusion model is described which, in conjunction with Henry's Law, is used to define oceanic redox conditions as a function of atmospheric oxygen content (expressed as % PAL, or Present Atmospheric Level) and climate during a period when the oceans presumably became ventilated as a consequence of photosynthetic 02 production and climate-induced changes in circulation. The results suggest that waters, especially equatorial shelf bottom waters, remained anoxic and sulfidic until atmospheric O2 increased to 3-5% PAL. Aerobic respiration may have been possible at 25% PAL in surface waters at high latitudes and 45% in the tropics. Dept. of Paleontology, Univ. of Calif., Berkeley, CA 94720, USA. (gsb)
D I S 0 . P a l e o n t o l o g y (see also E-BIOLOGICAL OCEANOGRAPHY) 87:6901 Baumfalk, Y.A., S.R. Troelstra, Gerald Ganssen and M.J.L. Van Zanen, 1987. Phonotyplc variation of G/oborota//a sc/tu/a (Foraminiferida) as a respouse to Plelsh3cone climatic fluctuations. Mar. Geol., 75(1-4):231-240.
Biometric analysis of five populations of G. scitula in Pleistocene piston cores from the eastern Mediterranean show morphologic variations that correlate with salinity fluctuations of the seawater. Increasing pore density of the test shows a remarkable correspondence to increasing 8~sO. Other morphologic
D. Submarine Geology and Geophysics
87:6895 Spanier, Ehud, 1987. A fossil record of shell boring: possible evidence for sea levd changes in the Red Sea. Estuar. coast. Shelf Sci., 24(6):873-879.
An aggregation of fossil shells of the Indo-Pacific muricid snails Chicoreus ramosus was found at a site 7 m above present mean sea level. Radiocarbon dating indicated an age of 1570-+80 yrBP. Some shells had bore-drilled holes, most uncompleted. Such holes were probably drilled by conspecifics in the absence of alternative food after disconnection from the sea. Since there is no evidence of human activity in this part of Tiran, such conditions could be caused only by a physical process that changed the relative water level. The character of the drilled holes and short period in which muricids maintain reproductive aggregates indicate a relatively rapid physical process. Dept. of Maritime Civilizations, Univ. of Haifa, Mount Carmel, Haifa 31999, Israel. 87:6896 Stea, R.R. and D.M. Wightman, 1987. Age of the Five Islands Formation, Nova Scotia, and the deglaclation of the Bay of Fundy. Quat. Res., 27(3):21 !-219.
Atomic mass spectrometry dating of shell material from the bottomset glaciomarine deltaic beds at Spencers Island, which are part of the previously undated Five Islands Formation, yields three ages between 14,300 and 12,600 yrBP, the first direct measurements for the time of deglaciation at the head of the Bay of Fundy. These dates are supported by similar radiocarbon dates obtained on ice margin glaciomarine deposits near St. John (New Brunswick) and imply that the bay became ice free about 14,000 yrBP. Nova Scotia Dept. of Mines and Energy, P.O. Box 1087, Halifax, NS, B3J 2XI, Canada. (hbf) 87:6897 Swift, S.A., 1987. Late Cretacemm-~nozoic development of outer continental m-rgin, southwestern Nova Scotia. Am. Ass. Petrol. Geol. Bull~ 71(6): 678-701.
Seismic stratigraphy and well data show that sediment accumulation was broadly controlled by sea level changes, although changes in sediment supply, morphology, current erosion, and salt tectonics were also significant. A Jurassic-Early Cretaceous carbonate platform controlled the location and steepness of the paleoslope until the Late Miocene, and local erosion of the outer shelf and slope in the Late Paleocene-Early Eocene produced chalky fans on the upper rise. Seaward extensions of Tertiary shelf-edge canyons are poorly defined
1053
except for the Eocene fans. Current eroded unconformities are common, but the only current deposit is a Pliocene interval restricted to the lowermost rise. Pleistocene turbidity currents have caused further erosion. WHOI, Woods Hole, MA 02543, USA. 87:6898 Traverse, Alfred, 1987. Pollen and spores date origin of rift basins from Texas to Nova Scotia as Early Late Triassic. Science, 236(4807):1469-1472. Dept. of Geosci., Pennsylvania State Univ., University Park, PA 16802, USA. 87:6899 Troelstra, S.R., 1987. Late Quaternary sedimentation in the Tyro and Kretheus basins, s o n t h n a of Crete. Mar. Geol~ 75(1-4):77-91. Geomar. Center Amsterdam, Free Univ., P.O. Box 7161, 1007 MC Amsterdam, Netherlands. 87:6900 Wilde, Pat, 1987. Model of progressive ventilation of the Late Preeambrhm-Early Paleozoic ocean. Am. J. Sci., 287(5):442-459.
A quantitative adveetion-diffusion model is described which, in conjunction with Henry's Law, is used to define oceanic redox conditions as a function of atmospheric oxygen content (expressed as % PAL, or Present Atmospheric Level) and climate during a period when the oceans presumably became ventilated as a consequence of photosynthetic 02 production and climate-induced changes in circulation. The results suggest that waters, especially equatorial shelf bottom waters, remained anoxic and sulfidic until atmospheric O2 increased to 3-5% PAL. Aerobic respiration may have been possible at 25% PAL in surface waters at high latitudes and 45% in the tropics. Dept. of Paleontology, Univ. of Calif., Berkeley, CA 94720, USA. (gsb)
D I S 0 . P a l e o n t o l o g y (see also E-BIOLOGICAL OCEANOGRAPHY) 87:6901 Baumfalk, Y.A., S.R. Troelstra, Gerald Ganssen and M.J.L. Van Zanen, 1987. Phonotyplc variation of G/oborota//a sc/tu/a (Foraminiferida) as a respouse to Plelsh3cone climatic fluctuations. Mar. Geol., 75(1-4):231-240.
Biometric analysis of five populations of G. scitula in Pleistocene piston cores from the eastern Mediterranean show morphologic variations that correlate with salinity fluctuations of the seawater. Increasing pore density of the test shows a remarkable correspondence to increasing 8~sO. Other morphologic