Golovchenko, Xenia; O'Connell, Suzanne B; Jarrard, Richard D (1990): Milankovitch frequency peaks of ODP Site 113-693 (Table 3) [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.754301, Supplement to: Golovchenko, X et al. (1990): Sedimentary response to paleoclimate from downhole logs at Site 693, Antarctic Continental Margin. In: Barker, PF; Kennett, JP; et al. (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 113, 239-251, https://doi.org/10.2973/odp.proc.sr.113.191.1990
Always quote citation above when using data! You can download the citation in several formats below.
Abstract:
The first well logs collected below the Antarctic circle were obtained during Leg 113 at Site 693 on the Dronning Maud Land Margin (Antarctica) in the Weddell Sea. Gamma-ray, resistivity, and sonic logs were collected between 108.0 and 439.0 mbsf. The downhole logs show good agreement with the data collected from cores and provide a continuous measurement of the sedimentary record. These continuous log records show that the rather uniform Tertiary lithology seen in cores is characterized by high-frequency variability in the log data. Several thin hard streaks are identified, the largest of which coincides with a major Miocene hiatus. Associated with this hiatus is a change to lower illite content (and correspondingly lower gamma-ray counts) and to a significant increase in diatom content.
Spectral analysis of the logs was performed on the lower Pliocene through upper Oligocene interval (108.0-343.0 mbsf). Between 108.0 and 245.0 mbsf, average sedimentation rates (50 and 26 m/m.y.) are high enough to show that variance is present in the orbital eccentricity (~95 k.y.) and obliquity (~41 k.y.) bands. Between 253.0 and 343.0 mbsf, the sedimentation rate (8 m/m.y.) is too low to resolve high frequency variations. The Milankovitch frequencies are best developed in the resistivity logs. Resistivity is responding to changes in porosity, which in these sediments is controlled by the abundance of biosiliceous sediments, particularly diatoms. The orbital forcing suggested by the Milankovitch frequencies may be influencing diatom productivity by inducing oscillations in upwelling, ice coverage, pack ice, and/or polynya. Although variations in diatom abundance were observed in the cores, they were not attributed to a Milankovitch signal, and therefore in this environment, downhole logs are an important contribution to the detection and understanding of orbitally influenced changes in sedimentation.
Project(s):
Ocean Drilling Program (ODP)
Coverage:
Latitude: -70.832000 * Longitude: -14.573950
Date/Time Start: 1987-01-30T00:00:00 * Date/Time End: 1987-02-07T00:00:00
Minimum DEPTH, sediment/rock: 127.5 m * Maximum DEPTH, sediment/rock: 225.5 m
Event(s):
113-693 * Latitude: -70.832000 * Longitude: -14.573950 * Date/Time Start: 1987-01-30T00:00:00 * Date/Time End: 1987-02-07T00:00:00 * Elevation: -2371.0 m * Penetration: 885.1 m * Recovery: 305.7 m * Location: Weddell Sea * Campaign: Leg113 * Basis: Joides Resolution * Method/Device: Composite Core (COMPCORE) * Comment: 69 cores; 651.3 m cored; 0 m drilled; 46.9% recovery
Comment:
Quality of interval frequency is determined by the presence or absence of the top or near top of an amplitude peak within ± 0.5 m.y. of the predicted frequency. Correlation: G = good, M = moderate, P = poor.
Parameter(s):
| # | Name | Short Name | Unit | Principal Investigator | Method/Device | Comment |
|---|---|---|---|---|---|---|
| 1 | DEPTH, sediment/rock | Depth sed | m | Geocode | ||
| 2 | Depth, top/min | Depth top | m | Golovchenko, Xenia | ||
| 3 | Depth, bottom/max | Depth bot | m | Golovchenko, Xenia | ||
| 4 | Sedimentation rate | SR | cm/ka | Golovchenko, Xenia | ||
| 5 | Interval frequency | Interval freq | Golovchenko, Xenia | 410 ka | ||
| 6 | Interval frequency | Interval freq | Golovchenko, Xenia | 95 ka | ||
| 7 | Interval frequency | Interval freq | Golovchenko, Xenia | 41 ka | ||
| 8 | Interval frequency | Interval freq | Golovchenko, Xenia | 23 ka | ||
| 9 | Interval frequency | Interval freq | Golovchenko, Xenia | 19 ka | ||
| 10 | Sample comment | Sample comment | Golovchenko, Xenia |
License:
Creative Commons Attribution 3.0 Unported (CC-BY-3.0)
Size:
90 data points