- About
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The Global ETD Search service is a free service for researchers
to find electronic theses and dissertations. This service is
provided by the
Networked Digital Library of Theses and Dissertations.
Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
Search results
Showing 291 to 300 of 463 (0.008 seconds)| 291 |
Sedimentological studies in the late precambrian upper vadsø group and lower tanafjord group of east Finnmark, north NorwayJohnson, H. D. January 1975 (has links)
No description available.
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| 292 |
Sedimentation of the Clastic Portions of The Underset and Little Limestone Cyclothems in Northern EnglandBin-Jantan, A. January 1978 (has links)
No description available.
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| 293 |
A comparative study of caledonian volcanics in wales and West NorwayFurnes, H. January 1978 (has links)
No description available.
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| 294 |
Petrogenesis and tectonic evolution of Yarlung Tsangpo ophiolites, south TibetChan, Heung Ngai January 2008 (has links)
Ophiolite complexes emplaced onto the Indian passive margin sequence in southwest Tibet represent the largest thrust sheet of the Neo-Tethyan oceanic crust and mantle that is preserved along the Yarlung Tsangpo Suture Zone (YTSZ). Field observations, petrological, geochemical and geochronological studies have revealed the supra-subduction zone (SSZ) type ophiolitic rocks formed in two different time frames, c. 127-124 Ma and c. ?4 Ma. The Early Cretaceous suite comprises voluminous mantle rocks, with subordinate mafic and ultramafic intrusions, while plutonic rocks are exposed locally. A shear zone complex probably representing a transform fault zone is also present. Geochemical analysis shows that the crustal rocks evolved from MORB-like to IAT to boninitic magmatism. The Late Cretaceous suite is represented by limited exposures of basaltic lavas, which have MORB-like geochemical compositions. Petrographic and geochemical evidence indicates that the majority of the mantle rocks are residues after extraction of MORB-type magma, which subsequently reacted with boninitic melts in a SSZ. Sub-ophiolite melange zones contain diverse rock types set in a serpentinte or mudstone matrix. Amongst a variety of lithologies, mid Jurassic and mid Cretaceous radiolarian cherts are exposed. Alkaline seamount volcanic rocks of inferred mid Cretaceous age were also found interbedded with cherts or overlain by limestones. Ophiolitic tholeiitic rocks were also included in the melange zones, two of which have 4°Ar_39Ar whole rock ages of c. 86 and 106 Ma. Evidence from the ophiolites and associated melange zones suggests that an intra-oceanic subduction zone initiated in the Early Cretaceous in this part of Neo-Tethyan Ocean. This SSZ system continued at least for c. 40 Ma, from the Early Cretaceous to Late Cretaceous.
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| 295 |
Origin of bedded cherts overlying ophiolitic rocks in the Italian north apennines, and implications of the ophiolite-pelagic sediment sequences for seafloor processesBarrett, T. J. January 1979 (has links)
No description available.
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| 296 |
Isotope and trace element studies of some basic igneous rocksHamilton, P. Jo January 1975 (has links)
No description available.
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| 297 |
Structural and Metamorphic Studies of Eclogites and Associated Rocks in the Central Tauern Region of the Eastern AlpsHolland, T. J. B. January 1977 (has links)
No description available.
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| 298 |
The roundstone ultrabasic complex connemara IrelandBremner, D. L. January 1977 (has links)
No description available.
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| 299 |
Petrography and Geochemistry of a Limestone-Shale Sequence with Early and Late Lithification: The Middle Purbeck of Dorset, EnglandEl-Shahat, A. January 1977 (has links)
No description available.
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| 300 |
Ultrasonic Velocity Measurements on Limestones from the Portland Group Correlation with Porosity and other Lithological FactorsCole, D. I. January 1975 (has links)
No description available.
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