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Continental margin brine seeps: their geological consequences
OLR(1987)34 (12)
D. SubmarineGeologyand Geophysics
1045
87:6846 Verhoef, Jacob, John Woodside and Ron Macnab, 1987. Geophysical mapping over the offshore region of eastern Canada. Eos, 68(24):577-579.
during lowstands of sea level. Elf Aquitaine Petroleum, 1000 Louisiana, Houston, TX 77002, USA.
Major collections of gravity and magnetic data have recently been compiled and combined with land data. Novel display techniques have been applied to these combined data sets, and the resulting maps are aiding in assessing regional geological relationships and helping define areas of specific interest for further quantitative interpretation. Bedford Inst. of Oceanogr., Dartmouth, Canada.
Paull, C.K. and A.C. Neumann, 1987. Continental margin brine seeps: their geological conseqnenoss. GeoloD,, geol. Soc. Am., 15(6):545-548.
D60.
Geomorphology(fans,
canyons, etc.) 87:6847
Flood, R.D. and J.E. Damuth, 1987. Quantitative characteristics of sinuous distributary channels on the Amazon Deep-Sea Fan. Geol. Soc. Am. Bull., 98(6):728-738. Analysis of GLORIA data on the middle and lower Amazon Fan demonstrates that relationships between meander wavelength and both channel width and meander radius are similar to those of large rivers, although channel width and depth decrease with distance down channel, and the slope along the channel axis decreases smoothly down fan. The data imply a dynamic relationship between valley and channel sinuosity, but it is not clear whether the meander pattern developed quickly during the early evolution of the system or more slowly as the system itself evolved. Lamont-Doherty Geol. Observ., Palisades, NY 10964, USA. (hbf)
87:6849
It is suggested that dissolved sulfides contained in brines seeping from the base of the escarpment corrode the limestone exposed there, resulting in the undercutting and steepening of the carbonate platform margins, which are 'among the steepest largescale features on Earth.' Bacterial chemosynthesis and sulfide mineralization have produced carbon and sulfide deposits found along the surface separating the buried escarpment from the onlapping sediments. Dept. of Geol., Univ. of North Carolina, Chapel Hill, NC 27514, USA. (hbf)
D70. Coasts, beaches, marshes 87:6850
Allen, J.R.L., 1987. Desiccation of mud in the temperate Intertidal zone. Studies from the Severn Estuary and eastern England. Phil. Trans. R. Soc., (B)315(1171):127-156. Dept. of Geol., The Univ., Reading RG6 2AB, UK. 87:6851 Allen, J.R.L., 1987. Late Flandrian shoreline oscillations in the Severn Estuary. The Rumney Formation at its typesite (Cardiff area). Phil. Trans. R. Soc., (B)315(1171):157-174. Dept. of Geol., The Univ., Reading, RG6 2AB, UK.
87:6848 Kolla, V. and F. Coumes, 1987. Morphology, internal structure, seismic stratigraphy, and sedimentation of Indus Fan. Am. Ass. Petrol. Geol. Bull., 71(6):650-677.
Bird, E.C.F., 1987. Viewpoint. The modern prevalenee of beach erosion. Mar. Pollut. Bull., 18(4): 151-157.
Seismic records reveal at least three canyon complexes on the shelf, each of which gave rise to leveed channels on the fan. The canyons and channels migrated extensively across the fan; channel abandonment and avulsion were common. Seismically, the canyon fill consists of several reflection-free zones overlain by inclined reflections of moderate amplitude, suggesting coarse-grained basal deposits fining upward to the top of the channel fill. The channels are flanked by wedge-shaped concaveupward reflection packages characteristic of leveeoverbank deposits. Sedimentation was primarily by channelized turbidity currents with overbank deposition on the upper fan and by both unchannelized and channelized turbidity currents on the lower fan
Surveys between 1972 and 1984 (by the International Geographical Union's Commission on the Coastal Environment) found that erosion has become prevalent on the sandy beaches that make up about one-fifth of the world's coastline. Although no single, simple explanation for the onset of beach erosion was found, fourteen factors contributing to the initiation or acceleration of erosion on sandy coastlines were identified. The Commission also investigated the processes which have led to progradation on the limited sectors where beaches have been built up and the responses made by coastal management agencies. The findings also apply, with minor exceptions and modifications, to the much less extensive shingle and gravel beaches of the
87:6852
D. SubmarineGeologyand Geophysics
1045
87:6846 Verhoef, Jacob, John Woodside and Ron Macnab, 1987. Geophysical mapping over the offshore region of eastern Canada. Eos, 68(24):577-579.
during lowstands of sea level. Elf Aquitaine Petroleum, 1000 Louisiana, Houston, TX 77002, USA.
Major collections of gravity and magnetic data have recently been compiled and combined with land data. Novel display techniques have been applied to these combined data sets, and the resulting maps are aiding in assessing regional geological relationships and helping define areas of specific interest for further quantitative interpretation. Bedford Inst. of Oceanogr., Dartmouth, Canada.
Paull, C.K. and A.C. Neumann, 1987. Continental margin brine seeps: their geological conseqnenoss. GeoloD,, geol. Soc. Am., 15(6):545-548.
D60.
Geomorphology(fans,
canyons, etc.) 87:6847
Flood, R.D. and J.E. Damuth, 1987. Quantitative characteristics of sinuous distributary channels on the Amazon Deep-Sea Fan. Geol. Soc. Am. Bull., 98(6):728-738. Analysis of GLORIA data on the middle and lower Amazon Fan demonstrates that relationships between meander wavelength and both channel width and meander radius are similar to those of large rivers, although channel width and depth decrease with distance down channel, and the slope along the channel axis decreases smoothly down fan. The data imply a dynamic relationship between valley and channel sinuosity, but it is not clear whether the meander pattern developed quickly during the early evolution of the system or more slowly as the system itself evolved. Lamont-Doherty Geol. Observ., Palisades, NY 10964, USA. (hbf)
87:6849
It is suggested that dissolved sulfides contained in brines seeping from the base of the escarpment corrode the limestone exposed there, resulting in the undercutting and steepening of the carbonate platform margins, which are 'among the steepest largescale features on Earth.' Bacterial chemosynthesis and sulfide mineralization have produced carbon and sulfide deposits found along the surface separating the buried escarpment from the onlapping sediments. Dept. of Geol., Univ. of North Carolina, Chapel Hill, NC 27514, USA. (hbf)
D70. Coasts, beaches, marshes 87:6850
Allen, J.R.L., 1987. Desiccation of mud in the temperate Intertidal zone. Studies from the Severn Estuary and eastern England. Phil. Trans. R. Soc., (B)315(1171):127-156. Dept. of Geol., The Univ., Reading RG6 2AB, UK. 87:6851 Allen, J.R.L., 1987. Late Flandrian shoreline oscillations in the Severn Estuary. The Rumney Formation at its typesite (Cardiff area). Phil. Trans. R. Soc., (B)315(1171):157-174. Dept. of Geol., The Univ., Reading, RG6 2AB, UK.
87:6848 Kolla, V. and F. Coumes, 1987. Morphology, internal structure, seismic stratigraphy, and sedimentation of Indus Fan. Am. Ass. Petrol. Geol. Bull., 71(6):650-677.
Bird, E.C.F., 1987. Viewpoint. The modern prevalenee of beach erosion. Mar. Pollut. Bull., 18(4): 151-157.
Seismic records reveal at least three canyon complexes on the shelf, each of which gave rise to leveed channels on the fan. The canyons and channels migrated extensively across the fan; channel abandonment and avulsion were common. Seismically, the canyon fill consists of several reflection-free zones overlain by inclined reflections of moderate amplitude, suggesting coarse-grained basal deposits fining upward to the top of the channel fill. The channels are flanked by wedge-shaped concaveupward reflection packages characteristic of leveeoverbank deposits. Sedimentation was primarily by channelized turbidity currents with overbank deposition on the upper fan and by both unchannelized and channelized turbidity currents on the lower fan
Surveys between 1972 and 1984 (by the International Geographical Union's Commission on the Coastal Environment) found that erosion has become prevalent on the sandy beaches that make up about one-fifth of the world's coastline. Although no single, simple explanation for the onset of beach erosion was found, fourteen factors contributing to the initiation or acceleration of erosion on sandy coastlines were identified. The Commission also investigated the processes which have led to progradation on the limited sectors where beaches have been built up and the responses made by coastal management agencies. The findings also apply, with minor exceptions and modifications, to the much less extensive shingle and gravel beaches of the
87:6852