O'Regan, A. Matthew (2007): Data report; Log-adjusted depth scales for Cretaceous black shale deposits from Demerara Rise

Leg/Site/Hole:
ODP 207
ODP 207 1257
ODP 207 1258
ODP 207 1259
ODP 207 1260
ODP 207 1261
Identifier:
2007-087733
georefid

10.2973/odp.proc.sr.207.113.2007
doi

Creator:
O'Regan, A. Matthew
University of Rhode Island, Graduate School of Oceanography, Narragansett, RI, United States
author

Identification:
Data report; Log-adjusted depth scales for Cretaceous black shale deposits from Demerara Rise
2007
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
Texas A&M University, Ocean Drilling Program, College Station, TX, United States
207
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.
English
Coverage:Geographic coordinates:
North:9.2800
West:-54.4400East: -54.1100
South:9.0200

Stratigraphy; Applied geophysics; Atlantic Ocean; boreholes; continental margin; cores; corrections; correlation; Cretaceous; data processing; Demerara Rise; density; depth; downhole methods; electrical methods; Equatorial Atlantic; French Guiana; gamma-ray methods; gamma-ray spectra; geophysical methods; high-resolution methods; Leg 207; lithostratigraphy; Mesozoic; North Atlantic; Northwest Atlantic; Ocean Drilling Program; ODP Site 1257; ODP Site 1258; ODP Site 1259; ODP Site 1260; ODP Site 1261; physical properties; reconstruction; resistivity; South America; spatial variations; spectra; stratigraphic gaps; Surinam; well logs; western Equatorial Atlantic;

.