O'Regan, A. Matthew (2007): Data report; Log-adjusted depth scales for Cretaceous black shale deposits from Demerara Rise. Texas A&M University, Ocean Drilling Program, College Station, TX, United States, In: Mosher, David C., Erbacher, Jochen, Malone, Mitchell J., Berti, Debora, Bice, Karen L., Bostock, Helen, Brumsack, Hans-Juergen, Danelian, Taniel, Forster, Astrid, Glatz, Christine, Heidersdorf, Felix, Henderiks, Jorijntje, Janecek, Thomas R., Junium, Christopher, Le Callonnec, Laurence, MacLeod, Kenneth G., Meyers, Philip A., Mutterlose, H. Joerg, Nishi, Hiroshi, Norris, Richard D., Ogg, James G., O'Regan, A. Matthew, Rea, Brice, Sexton, Philip, Sturt, Helen, Suganuma, Yusuke, Thurow, Juergen W., Wilson, Paul A., Wise, Sherwood W., Jr., Proceedings of the Ocean Drilling Program; scientific results; Demerara Rise; equatorial Cretaceous and Paleogene paleoceanographic transect, western Atlantic; covering Leg 207 of the cruises of the Drilling Vessel JOIDES Resolution; Bridgetown, Barbados, to Rio de Janeiro, Brazil; sites 1257-1261; 11 January-6 March 2003, 207, georefid:2007-087733

Abstract:
Multiple copies of Cretaceous black shales extending from the early Cenomanian to the end of the Santonian were recovered at five sites on Demerara Rise during Leg 207 of the Ocean Drilling Program. These sediments are primarily composed of laminated organic-rich claystones interbedded with coarser, lightly laminated foraminferal-bearing packstones and wackestones. The black shales represent the local expression of widespread organic-rich sedimentation in the Atlantic during the mid-Cretaceous. However, incomplete recovery prevented construction of continuous composite sections, resulting in uncertainties concerning the correct stratigraphic placement of individual cores. By combining high-resolution measurements of bulk density collected shipboard on the multisensor track with continuous downhole measurements of formation resistivity using the Formation MicroScanner, an equivalent logging depth scale was constructed for black shales recovered from Sites 1258, 1260, and 1261. The integrated depths approach centimeter-scale resolution and are supported by comparisons of coarser resolution natural gamma ray emissions collected on cores and through downhole logging operations. The new depths highlight the extent of both intra- and intercore gaps and provide an opportunity to further constrain temporal and spatial paleoceanographic changes captured in proxy records from these sediments.
Coverage:
West: -54.4400 East: -54.1100 North: 9.2800 South: 9.0200
Relations:
Expedition: 207
Site: 207-1257
Site: 207-1258
Site: 207-1259
Site: 207-1260
Site: 207-1261
Data access:
Provider: SEDIS Publication Catalogue
Data set link: http://sedis.iodp.org/pub-catalogue/index.php?id=10.2973/odp.proc.sr.207.113.2007 (c.f. for more detailed metadata)
Data download: application/pdf
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