Lithology, mineralogy and geochemistry of ODP Hole 118-735B and 176-735B respectively

Ocean Drilling Program (ODP) Hole 735B, located on Atlantis Bank on the Southwest Indian Ridge, penetrated 1508 meters below seafloor with an average recovery of 87%, providing a nearly continuous sample of a significant part of oceanic Layer 3. Based on variations in texture and mineralogy, 12 major lithologic units are recognized in the section, ranging from 39.5 to 354 m thick. The principal lithologies include troctolite, troctolitic gabbro, olivine gabbro and microgabbro, gabbro, gabbronorite and Fe-Ti oxide gabbro, gabbronorite, and microgabbro. Highly deformed mylonites, cataclasites, and amphibole gneisses are locally present, as are small quantities of pyroxenite, anorthositic gabbro, and trondhjemite. Downhole variations in mineral composition, particularly for olivine and clinopyroxene, show a number of cyclic variations. Plagioclase compositions show the widest variations and correspond to different degrees of deformation and alteration as well as primary processes. Downhole chemical variations correspond reasonably well with variations in mineral compositions. Iron and titanium mainly reflect the presence of Fe-Ti oxide gabbros but show some cyclical variations in the lower part of the core where oxide gabbros are sparse. CaO is highly variable but shows a small but consistent increase downhole. MgO is more uniform than CaO and shows a very small downward increase. Sulfur and CO2 contents are generally low, but S shows significant enrichment in lithologic Unit IV, which consists of Fe-Ti oxide gabbro, reflecting the presence of sulfide minerals in the sequence. The lithologic, mineralogical, and geochemical data provided here will allow detailed comparisons with ophiolite sections as well as sections of in situ ocean crust drilled in the future.

(Appendix) Late Cretaceous calcareous nannofossils of DSDP Holes 80-549 and 80-551

he early late Cretaceous (Cenomanian-early Turonian) is thought to have been one of the warmest periods of the Phanerozoic. This period was characterised by tropical sea surface temperatures of up to 36 °C and a pole-to-equator-gradient of less than 10 °C. The subsequent Turonian-Maastrichtian was characterised by a continuous climatic cooling, peaking in the Maastrichtian. This climatic cooling and the resulting palaeoceanographic changes had an impact on planktic primary producer communities including calcareous nannofossils. In order to gain a better understanding of these Cenomanian-Maastrichtian palaeoceanographic changes, calcareous nannofossils have been studied from the proto North Atlantic (Goban Spur, DSDP Sites 549, 551). In order to see potential differences between open oceanic and shelf dwelling nannofossils, the data from Goban Spur have been compared to findings from the European shelf (northern Germany). A total of 77 samples from Goban Spur were studied for calcareous nannofossils revealing abundant (mean 6.2 billion specimens/g sediment) and highly diverse (mean 63 species/sample) nannofossil assemblages. The dominant taxa are Watznaueria spp. (mean 30.7%), Prediscosphaera spp. (mean 18.3%), Zeugrhabdotus spp. (mean 8.3%), Retecapsa spp. (mean 7.2%) and Biscutum spp. (mean 6.6%). The Cenomanian assemblages of both Goban Spur (open ocean) and Wunstorf (shelf) are characterised by elevated abundances of high fertility taxa like Biscutum spp., Zeugrhabdotus spp. and Tranolithus orionatus. Early Turonian to Maastrichtian calcareous nannofossil assemblages of Goban Spur are, however, quite different to those described from European sections. Oceanic taxa like Watznaueria spp., Retecapsa spp. and Cribrosphearella ehrenbergii dominate in Goban Spur whereas the fertility indicators Biscutum spp. and T. orionatus are more abundant in the European shelf assemblages. This shift from a homogeneous distribution of calcareous nannofossils in the Cenomanian towards a heterogeneous one in the Turonian-Maastrichtian implies a change of the ocean circulation. The "eddy ocean" system of the Cenomanian was replaced by an oceanic circulation similar to the modern one in the Turonian-Maastrichtian, caused by the cooling. The increased pole-to-equator-gradients resulted in an oceanic circulation similar to the modern one.

El cantar de las hijas del Cid (fragmento de gesta)

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Performance characteristics of automotive engines in the United States. First series--report no. 12. 1975 Perkins diesel 247 CID (4.0 liters), F.I. Interim report.

Transportation Systems Center, Cambridge, Mass.

Performance characteristics of automotive engines in the United States. First series--report no. 13. 1975 American Motors 258 CID (4.2 liters), 1V. Interim report.

Transportation Systems Center, Cambridge, Mass.

Performance characteristics of automotive engines in the United States. Second series--report no. 1. 1976 Chevrolet Vega 140 CID (2.3 liters), 2V. Interim report.

Transportation Systems Center, Cambridge, Mass.

Performance characteristics of automotive engines in the United States. Second series--report no. 2. 1976 Chevrolet 305 CID (5.0 liters), 2V. Interim report.

Transportation Systems Center, Cambridge, Mass.

Performance characteristics of automotive engines in the United States. Second series--report no. 3. 1977 Chrysler 225 CID (3.7 liters), 2V. Interim report.

Transportation Systems Center, Cambridge, Mass.

Performance characteristics of automotive engines in the United States. First series--report no. 16. 1975 Volvo 121 CID (2.0 liters), F.I. Interim report.

Transportation Systems Center, Cambridge, Mass.

Performance characteristics of automotive engines in the United States. First series--report no. 17. 1975 Buick 455 CID (7.5 liters), 4V. Interim report.

Transportation Systems Center, Cambridge, Mass.National Highway Traffic Safety Administration, Office of Research and Development, Washington, D.C.

Performance characteristics of automotive engines in the United States. First series--report no. 18. 1976 Ford 400 CID (6.6 liters), 2V. Interim report.

Transportation Systems Center, Cambridge, Mass.

Performance characteristics of automotive engines in the United States. First series--report no. 19. 1975 Ford Windsor 351 CID (5.7 liters), 2V. Interim report.

Transportation Systems Center, Cambridge, Mass.

Performance characteristics of automotive engines in the United States. First series--report no. 20. 1975 Chevrolet 350 CID (5.7 liters) with Dresser variable - area Venturi system. Interim report.

Transportation Systems Center, Cambridge, Mass.

Performance characteristics of automotive engines in the United States. Second series--report no. 4. 1976 Chevrolet 85 CID (1.4 liters), 1V. Interim report.

Transportation Systems Center, Cambridge, Mass.

Performance characteristics of automotive engines in the United States. Second series--report no. 6. 1976 Nissan diesel 198 CID (3.2 liters), F.I. Interim report.

Transportation Systems Center, Cambridge, Mass.