Geology topics

Research about France

Source-linked reports with geographic coverage including France.

42 records · Page 3Linked to original sources

USGS1988

A test of uranium-series dating of fossil tooth enamel: Results from Tournal Cave, France

A series of well preserved mammal bones and horse teeth was analyzed from archaeological levels of Tournal Cave (Magdalenian, Aurignacian, and Mousterain) to test the hypothesis that well-crystallized enamel behaves more as a closed system than does whole bone. The isotopic composition of bones and tooth enamels from this deposit meet criteria for confidence, and gave no reasons to suspect contamination or open-system behavior. Two samples for which 231 Pa could be analyzed showed internal concordance with the respective 230 Th ages. In spite of the favourable isotopic criteria, however, comparison of the U-series ages of the bones and the tooth enamel with stratigraphic position and 14 C control indicated the dates were not meaningful. In general, both bones and tooth enamels gave ages too young, although some were clearly too old. Neither group showed any systematic increase of age with stratigraphic depth. Tooth enamel, therefore, shows no advantage over bone for U-series dating for this site. In Tournal cave both bones and enamel are apparently open to U, which is probably cycling as a consequences of post-depositional groundwater movement.

Applied Geochemistry↗

USGS1970

Paleomagnetic secular variation study of lavas from the Massif central, France

The angular standard deviation of virtual geomagnetic poles determined from a paleomagnetic study of 31 Brunhes-age lava flows from France has been obtained. The value, referred to the axial dipole (geographic axis), is 15.2° with 95% confidence limits of 18.4° and 12.9°. This value is not significantly different from that obtained in similar studies of lavas from other midlatitude localities (Western United States and New Zealand).

Earth and Planetary Science Letters↗

USGS1954

Contribution to the study of the physico-chemical structure of Clais

The Cormeilles-en-Parisis hill shows one of the best geologic sections of the Paris region. The 80 meter high working face of the quarry exposes the complete section of the "Ludian" [the youngest beds of the Eocene] with its alternations of the marl and gypsum. Above is the sequence of supra-gypseous marls of the [lower oligocene] Sannosian stage, overlain by a very complex series of alternation brackish water and lacustrine layers, from blue marls to Brie limestone, up through the white Pantin marls, brown marls containing the pelecypod genus Cyrena and green marls. These strata overlain by the [Middle Oligocene] Stampian beds represented by the Fontainebleau sands and Ostrea-bearing marls.

Cormeilles-en-Parisis↗

USGS1954

The landslide of Sainte-Adresse cliff

The Sainte-Adresse Cliff in the neighborhood of Le Havre was subject in the past to repeated movements of greater of lesser scope which in 1944 have become markedly accentuated because of works on the "Atlantic Wall" and bomb and mine explosions. The situation became dangerous and required a complete study including geological and geotechnical surveys with borings and search of slip planes. The study enabled us to explain the mechanism of the observed movements and to establish a program of consolidating works.

Sainte-Adresse Cliff↗

USGS1953

Measurement of earth pressure in the iron-ore mines of eastern France

The purpose of the tests, which will be reported later, is to measure as precisely as possible the tangential stresses exerted on the periphery of a gallery cut in the Lorraine iron ore. The values of the tangential stresses along the periphery being known, they will be compared with the values that would be given by the computations based on various hypotheseses, that of elasticity, perfect plasticity, masses with internal friction, irreversibility of stresses, stratified masses, etc.

Open-File Report↗

USGS1949

Fourth special report of the Hawaiian Volcano Observatory of the U.S. Geological Survey and the Hawaiian Volcano Research Association: Steam blast volcanic eruptions: A study of Mount Pelée in Martinique as type volcano

The investigation is concerned with the author's expedition to Martinique and St. Vincent in 1902 and comparison of the experience of investigators and sufferers with that of others in so-called "explosive" eruptions. The Hawaiian mechanism is reviewed with special reference to rifts, underground water, intrusion furnace, wedge rupture, and lowering of magma. These features of structure are applied to Martinique, St. Vincent, Kilauea, Tarawera, Sakurajima, Katmai, Taal and Tomboro as a series of steam blasts old and new. The comparison is found to be applicable and the analogy with Hawaii considered as fundamentally magmatic for gas and basaltic slag, brings out the contrast that lies in steam eruptions. For all volcanoes they are believed features of ground water and of collapse. Ground water stimulates lava eruptions. The Pelée disaster at St. Pierre May 8, 1902, followed by a dacite dome with spines, which renewed activity in 1929, is examined for paroxysms of downblast. These are distinguished sharply from the Carib migratory upblasts along valley fissures which are not uncommon elsewhere. The valleys are on rifts recognized as deep fumaroles. The Ghyben-Herzberg laws of ground water are applicable. Geyser rhythm was followed by Pelée, Soufriére of St. Vincent, and Kilauea in their sequence of paroxysms. Structure sections are drawn to scale, and the structural reactions of intrusion, rifts, boiler, gas effervescence, heat, and timing are thus outlined. The bearing of this machinery on volcanism in general, on world ignisepta and on reaction of magma is suggested. It is contended that steamblast is a climax of eruption in the water zone and should be sharply delimited from the rising and intrusion of fundamental earth magma, and from the high pressure water reactions of ocean bottoms. Rising magma is considered an age-long elevatory force along volcanic lines, modified by cyclical yielding. Compared with oceanic volcanism continental irruption in sediments is a separate science in experimental field geophysics. Every locality supramarine or submarine of warm ground and steep thermal gradient is a subject for volcanology, if pulsating ground water is critically, thermally and chemically measured. Authors are referred to herein by names and dates in parentheses, as listed in the appendices.

Martinique↗