ODP927: Marine record ODP927

In mcrucifix/pleistocene: Datasets of glacial cycles (ice and ocean)

Description

Benthic forams in Marine record ODP927 from Leg 154, Ceara Rise, Hole C

Usage

data(ODP927)

Format

	A data frame on the following variables.
Site	Site Number (here 927)
Hole	Hole Number (here A)
Core	Core Number (here 1)
Type
Sect
Top
mcd	mean sample core depth
d18O	d18O (per mil)
d13C	d13C (per mil)
species	benthic species only
Age	Age model according to Bickert et al., (see ref. below)

Details

HOLE 927B Date occupied: 1 March 1994 Date departed: 2 March 1994 Time on hole: 23 hr, 15 min Position: 5d27.774'N, 44d28.836'W Bottom felt (drill-pipe measurement from rig floor, m): 3326.5 Distance between rig floor and sea level (m): 11.3 Water depth (drill-pipe measurement from sea level, m): 3315.2 Total depth (from rig floor, m): 3588.0 Penetration (m): 261.5 Number of cores (including cores having no recovery): 28 Total length of cored section (m): 261.5 Total core recovered (m): 267.53 Core recovery (%): 102.3 Oldest sediment cored: Depth (mbsf): 261.5 Nature: nannofossil ooze with clay and foraminifers and clayey nannofos- sil ooze Age: middle Miocene Measured velocity (km/s): 1.9 Curry, W.B., Shackleton, N.J., Richter, C, et al., 1995. Proc. ODP, Ink. Repts., 154: College Station, TX (Ocean Drilling Program). 2 Shipboard Scientific Party is as given in the list of participants preceding the contents. Principal results: Site 927 is the second shallowest of the depth transect of sites on the Ceara Rise and also the site closest to the modern Amazon River. The site is located beneath warm surface waters having a mean temperature around 27dC. The seafloor at a depth of 3315 m is bathed by North Atlantic Deep Water (NADW) well above the present-day carbonate lysocline. The site was chosen to provide material for investigating the geologic history of surface- and deep-water properties in the region. Three holes were drilled at Site 927. Hole 927A was cored with the Af C to 312.5 mbsf. Hole 927B was cored with the APC from the mud line to 261.5 mbsf. Hole 927C was cored with the APC from the mud line to 228 mbsf and extended with the XCB to 266.7 mbsf. Hole 927C was deepened to 358 mbsf to enable the whole of the cored section to be logged, which it subse- quently was with the Quad combination tool. Detailed comparisons between the magnetic susceptibility records generated on the MST, and high-resolution color reflectance generated using a handheld Minolta color analyzer, demon- strated complete recovery of the sedimentary sequence to 266 mbsf. The recovered sedimentary sequence at Site 927 spans the interval from the early middle Miocene to the Holocene without any stratigraphic break detected, except for a clear hiatus between about 13 and 15 Ma. The entire sequence is characterized by rhythmic sedimentary cycles, and a preliminary evaluation suggests that these are chiefly related to the orbital precession cycle. These sedimentary cycles were well recorded by mag- netic susceptibility, color, and natural gamma-ray emission, and closely resemble the coeval cycles recorded in Sites 925 and 926. All these three parameters were shown to record variations in the ratio of terrigenous material to biogenic carbonate in the sediments. Because of a pervasive magnetic overprint, it proved impossible to obtain any magnetostrati- graphic data for the site. Biostratigraphic age control was provided by calcareous nannofossils and foraminifers throughout.

Source

Courtesy of F. Bassinot.

References

Shipboard Scientific Party, 1995. Site 927. In Curry, W.B., Shackleton, N.J., Richter, C., et al., Proc. ODP, Init. Repts., 154: College Station, TX (Ocean Drilling Program), 233-279 doi:10.2973/odp.proc.ir.154.106.1995 See http://www-odp.tamu.edu/publications/citations/cite154.html for complete list of scientific-result citations and references, and for notification of use of the present data.

Time scale: T. Bickert, W.B. Curry, and G. Wefer , 16. Late Pliocene to Holocene (2.6-0 ma) western equatorial atlantic deep-water circulation: inferences from benthic stable isotopes, in Shackleton, N.J., Curry, W.B., Richter, C., and Bralower, T.J. (Eds.), 1997 Proceedings of the Ocean Drilling Program, Scientific Results , Vol. 154 , pp. 239–253, http://www-odp.tamu.edu/publications/154_SR/16_CHAP.PDF

Examples

data(ODP927)
with(ODP927,plot(Age,d18O))

mcrucifix/pleistocene documentation built on May 22, 2019, 3:20 p.m.