Robertson, Alastair H. F. (2007): Geochemical evidence for the sedimentary and diagenetic development of the Mesozoic-early Cenozoic Newfoundland rifted margin, Northwest Atlantic (Ocean Drilling Program Leg 210, Site 1276). Texas A&M University, Ocean Drilling Program, College Station, TX, United States, In: Tucholke, Brian E., Sibuet, Jean-Claude, Klaus, Adam, Arnaboldi, Michela, Delius, Heike, Engstrom, Anna V., Galbrun, Bruno, Gardin, Silvia, Hiscott, Richard N., Karner, Garry D., Ladner, Bryan C., Leckie, R. Mark, Lee, Chao-Shing, Manatschal, Gianreto, Marsaglia, Kathleen M., Pletsch, Thomas K., Pross, Joerg, Robertson, Alastair H. F., Sawyer, Dale S., Sawyer, Derek E., Shillington, Donna J., Shirai, Masaaki, Shryane, Therese, Stant, Sharon Audra, Takata, Hiroyuki, Urquhart, Elspeth, Wilson, Chris, Zhao, Xixi, Proceedings of the Ocean Drilling Program; scientific results; drilling the Newfoundland half of the Newfoundland-Iberia transect; the first conjugate margin drilling in a nonvolcanic rift; covering Leg 210 of the cruises of the Drilling Vessel JOIDES Resolution; St. Georges, Bermuda, to St. John's, Newfoundland; sites 1276 and 1277; 6 July-6 September 2003, 210, georefid:2007-087761

Abstract:
Inorganic chemical composition and downhole variation of major and trace elements yields useful insights into the sediment provenance and paleoceanography of deep-sea sediments of deepwater continental margins. Here, fine-grained sediments were chemically analyzed at approximately 10-m intervals from the Eocene to Albian section at Site 1276. These sediments represent a time when background hemipelagic sedimentation was continuously beneath, or near, the calcite compensation depth (CCD). Additional samples were analyzed from the upper Paleocene-middle Eocene time interval to determine whether a volcaniclastic component is present, as suggested by petrographic studies of the coarser size fraction. Sediments recovered near the bottom of the hole show the effects of contact metamorphism adjacent to a sill of alkaline basalt. The overlying thick ( approximately 700 m) Albian succession (lithologic Unit 5) is indicative of a dominantly terrigenous source. Redox-sensitive trace elements (e.g., Cu, Ni, V, and Cr) are concentrated in organic-rich layers (black shales) that can be partially correlated with oceanic anoxic Events 1a-1d and 2. Beginning around the Cenomanian/Turonian boundary, a profound change took place to more oxidizing, slowly depositing sediments throughout the North Atlantic, characterized by relative enrichment in Fe, Mn, and related trace metals (e.g., Cu, Ni, and Cr). Similar background conditions persisted until the Eocene when local conditions at Site 1276 became more reducing, as indicated by more subdued colors and lower MnO contents. Moderate upwelling along the Newfoundland continental margin during the Eocene is suggested by the presence of relatively high values of silica coupled with opaline silica. Phosphate and associated trace elements (e.g., Ce and Y) are locally enriched, suggesting relatively high primary productivity. However, productivity was lower than on the conjugate Iberia margin at Deep Sea Drilling Project Site 398. Fine-grained terrigenous sediments at Site 1276 probably were mainly derived from the Grand Banks (e.g., Avalon uplift) and finally accumulated in deep water below the CCD mainly as mud turbidites and hemipelagites.
Coverage:
West: -44.4700 East: -44.4700 North: 45.2400 South: 45.2400
Relations:
Expedition: 210
Site: 210-1276
Expedition: 47
Site: 47-398
Data access:
Provider: SEDIS Publication Catalogue
Data set link: http://sedis.iodp.org/pub-catalogue/index.php?id=10.2973/odp.proc.sr.210.105.2007 (c.f. for more detailed metadata)
Data download: application/pdf
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