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Sea level changes in the past 600 years: possible archelogical significance
Oceanographic Abstracts
631
SERPOIANU GH. and V. CHIRILA,1963. Quelques particularit6s des conditions hydrologiques darts la r6gion nord-ouest de la Mer Noire. Rapp. Prec. Verb. Rdunions, Comm. Int., Exp. Sci., Met Mdd., Monaco, 17 (3): 917-922. Los auteurs exposent les r6sultats des recherehes hydrologiques effectu6es dans le r6gion nord-ouest de la Mer Noire, dans les mois de mai et juillet 1959 et juillet 1960. Ils mettent en 6vidence les partieularit6s sp6cifiques de cette r6gion marine, qui dans sa partie centrale pr6sente un caract/~re plus marin. Pour mettre en 6vidence ces particularit6s on expose en parall~le les donn6es obtenues en meme temps, dans la zone de Constantza. D'apr/:s les observations faites, il r6sulte que darts la r6gion 6tudi6e, bien qu'elle reqoive une grande quantit6 d'eau deuce--plus que dans d'autres secteurs de la Mer Noire--influence des eaux deuces est toutefois r6duite, surtout dans sa partie centrale. Cette chose s'explique par le syst~me des courants marins qui, d'apr~s les rechercbes de Knipovici, poussent les eaux deuces dans la r6gion e6ti~re. Dans la partie centrale de cette r6gion, on a trouv6 des valeurs de transparence et de salinit6 qui ressemblent aux valeurs maxima signal6es dans la Mer Noire. Los grandes valeurs de la salinit6 superficielle et les petites profondeurs--d'habitude moins de 50 m--permettent une bonne circulation vertieale entre les eaux de surface et celles du fond. Ainsi est assur6 le circuit normal des substances min6rales et biog~,nes, fait qui a une influence positive sur la productivit6 de cette r6gion marine. SHAW W. N. and J. A. MCCANN,1963. Comparison of growth of four strains of oysters raised in Taylors pond, Chatham, Massachusetts. U. S. Fish. Wild. Sere., Fish. Ball., 63 (1): 11-18. Former buyers of Wareham River, Massachusetts, seed oysters claim that these oysters are slow growing and have a high mortality rate. The purpose of this experiment was to determine whether Wareham River oysters are truly slow growing. Seed oysters from Wareham River, Mill Creek, Massachusetts; Long Island Sound, Connecticut; and James River, Virginia, were suspended side by side from a Fiberglas raft in Taylors Pond, Chatham, Mass. from autumn 1958 to autumn 1960. The growth rates for all strains were determined and then compared. At the end of 1958 the Mill Creek oyster strain was significantly larger than the other three strains. During 1959 the growth rate of the Wareham River strain was significantly slower than those of the Long Island Sound and Mill Creek strains. During 1960 the growth rates of all strains were significantly similar. At the end of 1960 the oysters from Wareham River were significantly smaller than those from Mill Creek and Long Island Sound. The study demonstrates that in a single environment the Wareham River oysters grow slower than oysters from Long Island Sound and Mill Creek. Further studies are necessary to determine the reasons for this apparent slow growth. SrmPARO F. P., 1964. Sea level changes in the past 6000 years: possible archeological significance.
Science, 143 (3606): 574--576. Evidence from many stable areas indicates that sea level has risen slowly during the past 6000 yr, with a total change of about 6 m. Since the same period is also important in the history of man, the rise in sea level explains the widespread submergence o f building sites and other h u m a n relics along coasts where ancient man lived. SHEPARD FRANCIS P., 1964. Sea-floor valleys of Gulf o f California. In: Marine geology of the Gulf of California, a symposium. Amer. Ass. Petrol. Geol., Memoir, (Edited by VAN ANDEL T. and GEORG~ G. SHOR JR.), 3: 157-192. Valleys of various types have been found in the G u l f of California. Of these the most impressive is the series of deeply incised canyons that extend down the slopes around the lower end of Baja California. Crystalline rocks together with sedimentary formations of Miocene and Pliocene age have been dredged from the steep walls of these canyons. The canyons head near the shore and wind outward with many dendritic tributaries terminating at depths from about 900 to 1300 fm. Narrow vertical to overhanging walled gorges at the head o f some of these canyons, very different from local land canyons, are probably being excavated at the present time by the sand flows and other gravity-induced movements which have been observed along their steep courses. Sand with underlying gravel and rock fragments found in cores and box samples have been taken from the canyon axes over a wide range of depths. These indicate that a scouting action is working on the canyon floor. Despite these evidences of present-day marine erosion it seems likely that the pattern of the valleys was established by old, deeply submerged stream valleys that have been considerably modified by marine processes, especially as they sank below sea level. Some valleys of the G u l f floor are the result of tectonism and it is possible that such movements may have helped form the canyons. In one place a canyon appears to have been cut off by faulting, and in another place a narrow gorge cuts through what appears to be a fault scarp. Other valleys owe their origin entirely to slumping and other types of mass movements on the steep slopes. This last group, like the tectonic valleys, is very distinct in character from the eroded canyons. A problem of considerable interest is the explanation of the deeply weathered granitic rocks found on the walls of several of the canyons.
631
SERPOIANU GH. and V. CHIRILA,1963. Quelques particularit6s des conditions hydrologiques darts la r6gion nord-ouest de la Mer Noire. Rapp. Prec. Verb. Rdunions, Comm. Int., Exp. Sci., Met Mdd., Monaco, 17 (3): 917-922. Los auteurs exposent les r6sultats des recherehes hydrologiques effectu6es dans le r6gion nord-ouest de la Mer Noire, dans les mois de mai et juillet 1959 et juillet 1960. Ils mettent en 6vidence les partieularit6s sp6cifiques de cette r6gion marine, qui dans sa partie centrale pr6sente un caract/~re plus marin. Pour mettre en 6vidence ces particularit6s on expose en parall~le les donn6es obtenues en meme temps, dans la zone de Constantza. D'apr/:s les observations faites, il r6sulte que darts la r6gion 6tudi6e, bien qu'elle reqoive une grande quantit6 d'eau deuce--plus que dans d'autres secteurs de la Mer Noire--influence des eaux deuces est toutefois r6duite, surtout dans sa partie centrale. Cette chose s'explique par le syst~me des courants marins qui, d'apr~s les rechercbes de Knipovici, poussent les eaux deuces dans la r6gion e6ti~re. Dans la partie centrale de cette r6gion, on a trouv6 des valeurs de transparence et de salinit6 qui ressemblent aux valeurs maxima signal6es dans la Mer Noire. Los grandes valeurs de la salinit6 superficielle et les petites profondeurs--d'habitude moins de 50 m--permettent une bonne circulation vertieale entre les eaux de surface et celles du fond. Ainsi est assur6 le circuit normal des substances min6rales et biog~,nes, fait qui a une influence positive sur la productivit6 de cette r6gion marine. SHAW W. N. and J. A. MCCANN,1963. Comparison of growth of four strains of oysters raised in Taylors pond, Chatham, Massachusetts. U. S. Fish. Wild. Sere., Fish. Ball., 63 (1): 11-18. Former buyers of Wareham River, Massachusetts, seed oysters claim that these oysters are slow growing and have a high mortality rate. The purpose of this experiment was to determine whether Wareham River oysters are truly slow growing. Seed oysters from Wareham River, Mill Creek, Massachusetts; Long Island Sound, Connecticut; and James River, Virginia, were suspended side by side from a Fiberglas raft in Taylors Pond, Chatham, Mass. from autumn 1958 to autumn 1960. The growth rates for all strains were determined and then compared. At the end of 1958 the Mill Creek oyster strain was significantly larger than the other three strains. During 1959 the growth rate of the Wareham River strain was significantly slower than those of the Long Island Sound and Mill Creek strains. During 1960 the growth rates of all strains were significantly similar. At the end of 1960 the oysters from Wareham River were significantly smaller than those from Mill Creek and Long Island Sound. The study demonstrates that in a single environment the Wareham River oysters grow slower than oysters from Long Island Sound and Mill Creek. Further studies are necessary to determine the reasons for this apparent slow growth. SrmPARO F. P., 1964. Sea level changes in the past 6000 years: possible archeological significance.
Science, 143 (3606): 574--576. Evidence from many stable areas indicates that sea level has risen slowly during the past 6000 yr, with a total change of about 6 m. Since the same period is also important in the history of man, the rise in sea level explains the widespread submergence o f building sites and other h u m a n relics along coasts where ancient man lived. SHEPARD FRANCIS P., 1964. Sea-floor valleys of Gulf o f California. In: Marine geology of the Gulf of California, a symposium. Amer. Ass. Petrol. Geol., Memoir, (Edited by VAN ANDEL T. and GEORG~ G. SHOR JR.), 3: 157-192. Valleys of various types have been found in the G u l f of California. Of these the most impressive is the series of deeply incised canyons that extend down the slopes around the lower end of Baja California. Crystalline rocks together with sedimentary formations of Miocene and Pliocene age have been dredged from the steep walls of these canyons. The canyons head near the shore and wind outward with many dendritic tributaries terminating at depths from about 900 to 1300 fm. Narrow vertical to overhanging walled gorges at the head o f some of these canyons, very different from local land canyons, are probably being excavated at the present time by the sand flows and other gravity-induced movements which have been observed along their steep courses. Sand with underlying gravel and rock fragments found in cores and box samples have been taken from the canyon axes over a wide range of depths. These indicate that a scouting action is working on the canyon floor. Despite these evidences of present-day marine erosion it seems likely that the pattern of the valleys was established by old, deeply submerged stream valleys that have been considerably modified by marine processes, especially as they sank below sea level. Some valleys of the G u l f floor are the result of tectonism and it is possible that such movements may have helped form the canyons. In one place a canyon appears to have been cut off by faulting, and in another place a narrow gorge cuts through what appears to be a fault scarp. Other valleys owe their origin entirely to slumping and other types of mass movements on the steep slopes. This last group, like the tectonic valleys, is very distinct in character from the eroded canyons. A problem of considerable interest is the explanation of the deeply weathered granitic rocks found on the walls of several of the canyons.