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Showing papers in "Earth and Planetary Science Letters in 1981"


Journal ArticleDOI
TL;DR: In this paper, the mass assimilation rate is an arbitrary fraction(r) of the fractional crystallization rate, where r < 1 is a combination of zone refining and fractional scaling.

3,033 citations


Journal ArticleDOI
TL;DR: In this article, 16 sets of apatite/liquid partition coefficients (Dap/liq) for the rare earth elements (REE; La, Sm, Dy, Lu) and six values for Sr were experimentally determined in natural systems ranging from basanite to granite.

450 citations


Journal ArticleDOI
TL;DR: Lead concentrations were determined by isotope dilution mass spectrometry in 34 surface and deepwater samples collected in the northeast Pacific between Hawaii and California and off the California coast using a deep-water sampler protected against fouling by contamination from the ship and hydrowire.

416 citations


Journal ArticleDOI
TL;DR: In the later part of the Pleistocene, variations in global ice volume have been dominated by an approximate 100,000-year cycle as discussed by the authors, and this is true only for the last 900,000 years.

408 citations


Journal ArticleDOI
TL;DR: In this paper, the authors concluded that the most prominent layering in the crust is not compositional but metamorphic, and that the continental crust is characterized by lateral and vertical heterogeneities of varying scale which are the apparent cause of the complex seismic reflections recorded by COCORP.

376 citations


Journal ArticleDOI
TL;DR: The concentrations of cadmium, zinc, copper and barium have been determined on 2-mg samples of single-species foraminifera populations Cleaning techniques were tested using North Atlantic core tops, and followed by a detailed downcore study for the last 30,000 years in South Atlantic core V22-174 as discussed by the authors.

372 citations


Journal ArticleDOI
TL;DR: In this paper, the mineralogy of the samples has been determined by X-ray diffractometry, scanning electron microscopy, and Xray energy dispersive analysis from eight active and inactive vent sites along the East Pacific Rise at 21°N during the RISE expedition of April 1979.

332 citations


Journal ArticleDOI
TL;DR: In this paper, a plot of isochron slope versus intercept was used to show that the points describing each island's Pb-Pb array all lie very near a single straight line.

330 citations


Journal ArticleDOI
TL;DR: The tectonic history of Afghanistan appears to be the result of successive accretion of fragments of Gondwana to the active margin of Laurasia since the end of the Paleozoic.

287 citations


Journal ArticleDOI
TL;DR: In this paper, 40Ar/39Ar age spectrum analyses of samples from Broken Hill, New South Wales, indicate that the region has experienced a complex thermal history following high-grade metamorphism, 1660 Ma ago.

279 citations


Journal ArticleDOI
TL;DR: In this paper, gas hydrates were brought up for the first time from two holes (497, 498A) drilled during Leg 67 of the DSDP in water depths of 2360 and 5500 m, respectively.

Journal ArticleDOI
TL;DR: In this article, the authors present evidence for recent normal faulting in the Cordillera Blanca of Peru along planes trending approximately N40°W, parallel to the chain.

Journal ArticleDOI
TL;DR: In this article, a high-precision tree-ring record of the atmospheric 14C levels between 1820 and 1954 is presented, and good agreement is obtained between measured and model calculated 19th and 20th century atmospheric Δ14C levels when both fossil fuel CO2 release and predicted natural variations in 14C production are taken into account.

Journal ArticleDOI
TL;DR: In this article, the authors developed a model which included a dissolved-particulate transformation as well as parameters of the scavenging model and applied it to the vertical distributions of total and GEOSECS particulate Th isotopes ( 230 Th and 234 Th).

Journal ArticleDOI
TL;DR: In this paper, it was shown that ascent beneath the arc axial chain of a line of diapirs of MORB-source mantle interferes with processes of arc magma generation and arc magmatism wanes.

Journal ArticleDOI
TL;DR: In this article, it is estimated that ca. 1 × 10 10 moles of strontium are cycled in the hydrothermal systems of mid-oceanic ridges, thereby affecting the 87 Sr/86 Sr budget of seawater.

Journal ArticleDOI
TL;DR: In this paper, the concentrations and isotopic composition of helium in oceanic basaltic glass both by melting and by crushing in vacuo were determined and a significant fraction of the helium was released by crushing, confirming that it resides within the vesicles.

Journal ArticleDOI
TL;DR: The dominance of volcanic processes and the importance of vertical tectonics in the geological evolution of the Pacific Basin has been recognised since the time of Charles Darwin this article, and data gathered on several legs of Deep Sea Drilling Project (DSDP) and numerous marine expeditions in the past decade have confirmed Menard's postulate that the Pacific basin was the scene of volcanism on an enormous scale in Mesozoic time.

Journal ArticleDOI
TL;DR: In this article, the equivalence points of the carbonic acid system on this titration curve were developed in 1971 but have not previously been published, and applied to the GEOSECS program by computer-controlled potentiometric titration technique.

Journal ArticleDOI
TL;DR: In this paper, the relationship between magnetic susceptibility anisotropy, finite strain, and progressive deformation has been studied in Permian red shales and slates of the Maritime Alps (southeastern France).

Journal ArticleDOI
TL;DR: In this article, the authors show that the oceanic crust alters in four distinct stages characterized by formation of palagonite, smectite and calcite (Stages I, II and III, respectively).

Journal ArticleDOI
TL;DR: The unusual petrological diversity of abyssal lavas erupted along some segments of the Galapagos spreading center is a direct consequence of the propagation (elongation) of these segments into older oceanic crust as discussed by the authors.

Journal ArticleDOI
TL;DR: In this article, the geochemistry of Lewisian amphibolite-facies gneisses from northwest Scotland is described with particular reference to the rare earth elements (REE) and compared with the geochemical properties of the Lewisian granulite-fa-susceptible granulites.

Journal ArticleDOI
TL;DR: In this paper, the mineralogy and isotopic composition of sulfur found in hydrothermal deposits associated with five groups of vents along the ridge axis of the East Pacific Rise near 21 deg N latitude are investigated.

Journal ArticleDOI
TL;DR: In this paper, it was shown that the Aleutian arc magmas could not have been derived directly from homogeneous MORB-type mantle, or fresh or altered MORB subducted beneath the arc.

Journal ArticleDOI
TL;DR: In this article, a plate tectonic model was proposed to explain the Early/Middle Ordovician erosional unconformity observed along much of the western margin of the Appalachian orogen.

Journal ArticleDOI
TL;DR: In this article, the rotation age of Sardinia relative to Europe within a rather short time span of 1.5 Ma between 20.5 and 19 Ma was established by correlation of the results with the geomagnetic time scale.

Journal ArticleDOI
TL;DR: In this article, the magnetic grains isolated from magnetococcoid bacterial cells were studied by means of transmission electron microscopy, electron diffraction and electron microprobe analysis, which supported the contention that the magnetic bacterial grains are single-domain crystals capable of producing a natural remanent magnetization in sediments.

Journal ArticleDOI
TL;DR: In this paper, two older granitic rocks and some selected Quaternary volcanic rocks from the Japanese Islands were analyzed in a reconnaissance study for the purpose of examining the relationships between Nd and Sr isotopic abundances and the megatectonic structure around the Japanese islands.