Explanatory notes

,

doi:10.2973/odp.proc.ir.155.104.1995

Cited by 5 publications

(3 citation statements)

References 59 publications

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“…However, it is IODP practice to discard physical properties data from the top and bottom of core sections to avoid such end effects. In addition, drill holes through the core liner can affect the core itself, by forming small indents and more pervasive deformation of the sediments, and locally depleting the sediments from very fine grains [Flood et al, 1995]. In very rare and extreme cases, for instance where fully liquefied sands are present in the lower part of a core that experienced partial stroke, the core sections have to be stood vertically to separate sediments from water by gravity ( Figure 9f) before sectioning can be undertaken.…”

Section: Deformation Due To Core Recovery and Transport On Deckmentioning

confidence: 99%

“…Depressurization of core, with expansion and escape of gas (particularly methane in continental settings) from muddy sediments, can occur for hours after the core arrives on deck [Flood et al, 1995]. Striking examples occurred when sectioning cores on the cat walk during Expedition 340.…”

Section: Other Disturbancesmentioning

confidence: 99%

“…In addition, the presence of firm mud at the bottom of certain cores acted like a plug in the core catchers, preventing unconsolidated sand from escaping. This study does not discuss disturbances during XCB (Extended Core Barrel) and RCB (Rotary Core Barrel) drilling [e.g., Piper, 1975;Kidd et al, 1978;Francis et al, 1982;Flood et al, 1995;Huey, 2009].…”

Section: Introductionmentioning

confidence: 99%

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Coring disturbances in IODP piston cores with implications for offshore record of volcanic events and the Missoula megafloods

Jutzeler

White

Talling

et al. 2014

Geochem. Geophys. Geosyst.

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Piston cores collected from IODP drilling platforms (and its predecessors) provide the best long-term geological and climatic record of marine sediments worldwide. Coring disturbances affecting the original sediment texture have been recognized since the early days of coring and include deformation resulting from shear of sediment against the core barrel, basal flow-in due to partial stroke, loss of stratigraphy, fall-in, sediment loss through core catchers, and structures formed during core recovery and on-deck transport. The most severe disturbances occur in noncohesive (sandy) facies, which are particularly common in volcanogenic environments and submarine fans. Although all of these types of coring disturbances have been recognized previously, our contribution is novel because it provides an easily accessible summary of methods for their identification. This contribution gives two specific examples on the importance of these coring disturbances. We show how suck-in of sediments during coring artificially created very thick volcaniclastic sand layers in cores offshore Montserrat and Martinique (Lesser Antilles). We then analyze very thick, structureless sand layers from the Escanaba Trough inferred to be a record of the Missoula megafloods. These sand layers tend to coincide with the base of core sections, and their facies suggest coring disturbance by basal flow-in, destroying the original structure and texture of the beds. We conclude by outlining and supporting IODP-led initiatives to further reduce and identify coring disturbances and acknowledge their recent successes in drilling challenging sand-rich settings, such as during IODP Expedition 340.

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Section: Deformation Due To Core Recovery and Transport On Deckmentioning

confidence: 99%

Section: Other Disturbancesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Coring disturbances in IODP piston cores with implications for offshore record of volcanic events and the Missoula megafloods

Jutzeler

White

Talling

et al. 2014

Geochem. Geophys. Geosyst.

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Paleomagnetic record determined in cores from deep research wells in the Quaternary Santa Clara basin, California

Mankinen

Wentworth

2016

Geosphere

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Paleomagnetic study of cores from six deep wells provides an independent temporal framework for much of the alluvial stratigraphy of the Quaternary basin beneath the Santa Clara Valley. This stratigraphy consists of 8 upward-fining cycles in the upper 300 m of section and an underlying 150 m or more of largely fine-grained sediment. The eight cycles have been correlated with the marine oxygen isotope record, thus providing one means of dating the section. The section has also proved to contain a rich paleomagnetic record despite the intermittent sedimentation characteristic of alluvial environments. Each well was designed to reach a depth of ~300 m, although 2 were terminated at shallower depth where bedrock was encountered and one (GUAD) was deepened to bedrock at 407.2 m. Cores were taken at intermittent intervals in most of the wells, composing ~20%-25% of their depths. In GUAD an attempt was made to core the entire upper 300 m, with core recovery of 201.8 m (67%). The paleomagnetic framework ranges from the 32 ka Mono Lake excursion near the top of the second sedimentary cycle to below the 780 ka Brunhes-Matuyama geomagnetic reversal beneath the eighth cycle. These ages nicely fit those assigned to the section based on correlation with the marine oxygen isotope record. Several episodes of anomalous magnetic inclinations were also found within the cyclic section in some of the wells. Some of the episodes of anomalous magnetic inclinations are only separated by short normal intervals in a pattern similar to that described for some welldocu mented excursions. We consider that a geomagnetic excursion was likely only if the anomalous inclinations were found at approximately the same stratigraphic position in more than one drill hole. A deeper time constraint is provided by the upper boundary (990 ka) of the Jaramillo Normal Polarity Subchron recognized at a depth of 302 m in one deeply penetrating well (GUAD). Approximately 100 m of normal Jaramillo section is evident below that in wells GUAD and EVGR. The reversal that we identify as the 780 ka Brunhes-Matuyama boundary, found at depths of 291-303 m in three wells, indicates an average rate of deposition in this upper section of ~37 cm/k.y. In GUAD, the top of the underlying normally polarized section, which we assign to the upper part of the Jaramillo Normal Polarity Subchron, was found between 301.8 and 304.5 m. The resultant 10 m of reversed polarity section above the Jaramillo seems anomalously short for this 210 k.y. part of the Matuyama Chron, during which several times that thickness of section probably should have accumulated. This observation indicates that a significant unconformity should be present in that short section between the Jaramillo Subchron and the Brunhes-Matuyama boundary. Deeper cores in two wells (GUAD and EVGR) all have normal polarity and seem to represent much of the Jaramillo Subchron, although no base for that subchron was found. The resultant minimum rate of sedimentation for this lower section beneath the unconformity is 170 cm/k....

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Expedition 353 methods

Clemens¹,

Kuhnt²,

LeVay³

et al. 2016

Proceedings of the International Ocean Discovery Program

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Explanatory notes

Abstract: The separate sections of the site chapters were written by the following shipboard scientists (authors are listed in alphabetical order; no seniority is implied):

Cited by 5 publications

References 59 publications

Coring disturbances in IODP piston cores with implications for offshore record of volcanic events and the Missoula megafloods

Coring disturbances in IODP piston cores with implications for offshore record of volcanic events and the Missoula megafloods

Paleomagnetic record determined in cores from deep research wells in the Quaternary Santa Clara basin, California

Expedition 353 methods

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