Footwall rotation in an oceanic core complex quantified using reoriented Integrated Ocean Drilling Program core samples

Integrated Ocean Drilling Program (IODP) Expedition 340T returned to the 1.4-km-deep Hole U1309D at Atlantis Massif to carry out borehole logging including vertical seismic profiling (VSP). Seismic, resistivity, and temperature logs were obtained throughout the geologic section in the footwall of this oceanic core complex. Reliable downhole temperature measurements throughout and the first seismic coverage of the 800–1400 meters below seafloor (mbsf) portion of the section were obtained. Distinct changes in velocity, resistivity, and magnetic susceptibility characterize the boundaries of altered, olivine-rich troctolite intervals within the otherwise dominantly gabbroic se-quence. Some narrow fault zones also are associated with downhole resistivity or velocity excursions. Small deviations in temperature were measured in borehole fluid adjacent to known faults at 750 mbsf and 1100 mbsf. This suggests that flow of seawater remains active along these zones of faulting and rock alteration. Vertical seismic profile station coverage at zero offset now extends the full length of the hole, including the uppermost 150 mbsf, where detachment processes are expected to have left their strongest imprint. Analysis of wallrock properties, together with alteration and structural characteristics of the cores from Site U1309, highlights the likely interplay between lithology, structure, lithospheric hydration, and core complex evolution. doi:<a href="http://dx.doi.org/10.2204/iodp.sd.15.04.2013" target="_blank">10.2204/iodp.sd.15.04.2013</a>

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Seismic slip propagation to the updip end of plate boundary subduction interface faults: Vitrinite reflectance geothermometry on Integrated Ocean Drilling Program NanTro SEIZE cores

Geology ◽

10.1130/g31642.1 ◽

2011 ◽

Vol 39 (4) ◽

pp. 395-398 ◽

Cited By ~ 116

Author(s):

A. Sakaguchi ◽

F. Chester ◽

D. Curewitz ◽

O. Fabbri ◽

D. Goldsby ◽

...

Keyword(s):

Vitrinite Reflectance ◽

Plate Boundary ◽

Ocean Drilling Program ◽

Seismic Slip ◽

Ocean Drilling ◽

Integrated Ocean Drilling Program

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IODP Expedition 318: From Greenhouse to Icehouse at the Wilkes Land Antarctic Margin

Scientific Drilling ◽

10.5194/sd-12-15-2011 ◽

2011 ◽

Vol 12 ◽

pp. 15-23 ◽

Cited By ~ 16

Author(s):

C. Escutia ◽

H. Brinkhuis ◽

A. Klaus ◽

Keyword(s):

Middle Eocene ◽

Second Phase ◽

Last Deglaciation ◽

Ocean Drilling Program ◽

Ocean Drilling ◽

Integrated Ocean Drilling Program ◽

Tectonic History ◽

Wilkes Land ◽

History Of

Integrated Ocean Drilling Program (IODP) Expedition 318, Wilkes Land Glacial History, drilled a transect of sites across the Wilkes Land margin of Antarctica to provide a long-term record of the sedimentary archives of Cenozoic Antarctic glaciation and its intimate relationships with global climatic and oceanographic change. The Wilkes Land drilling program was undertaken to constrain the age, nature, and paleoenvironment of the previously only seismically inferred glacial sequences. The expedition (January–March 2010) recovered ~2000 meters of high-quality middle Eocene–Holocene sediments from water depths between 400 m and 4000 m at four sites on the Wilkes Land rise (U1355, U1356, U1359, and U1361) and three sites on the Wilkes Land shelf (U1357, U1358, and U1360). These records span ~53 million years of Antarctic history, and the various seismic units (WL-S4–WL-S9) have been successfully dated. The cores reveal the history of the Wilkes Land Antarctic margin from an ice-free “greenhouse” Antarctica, to the first cooling, to the onset and erosional consequences of the first glaciation and the subsequent dynamics of the waxing and waning ice sheets, all the way to thick, unprecedented "tree ring style" records with seasonal resolution of the last deglaciation that began ~10,000 y ago. The cores also reveal details of the tectonic history of the Australo-Antarctic Gulf from 53 Ma, portraying the onset of the second phase of rifting between Australia and Antarctica, to ever-subsiding margins and deepening, to the present continental and ever-widening ocean/continent configuration. doi:<a href="http://dx.doi.org/10.2204/iodp.sd.12.02.2011" target="_blank">10.2204/iodp.sd.12.02.2011</a>

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IODP Expedition 335: Deep Sampling in ODP Hole 1256D

Scientific Drilling ◽

10.5194/sd-13-28-2012 ◽

2012 ◽

Vol 13 ◽

pp. 28-34 ◽

Cited By ~ 10

Author(s):

D. A. H. Teagle ◽

B. Ildefonse ◽

P. Blum ◽

Keyword(s):

Theoretical Models ◽

Spreading Rate ◽

Ocean Crust ◽

Ocean Drilling Program ◽

Drill Cuttings ◽

Ocean Drilling ◽

Ocean Ridges ◽

Integrated Ocean Drilling Program ◽

Geological Conditions ◽

Ocean Lithosphere

Observations of the gabbroic layers of untectonized ocean crust are essential to test theoretical models of the accretion of new crust at mid-ocean ridges. Integrated Ocean Drilling Program (IODP) Expedition 335 ("Superfast Spreading Rate Crust 4") returned to Ocean Drilling Program (ODP) Hole 1256D with the intention of deepening this reference penetration of intact ocean crust a significant distance (~350 m) into cumulate gabbros. Three earlier cruises to Hole 1256D (ODP 206, IODP 309/312) have drilled through the sediments, lavas, and dikes and 100 m into a complex dike-gabbro transition zone. Operations on IODP Expedition 335 proved challenging throughout, with almost three weeks spent re-opening and securing unstable sections of the hole. When coring commenced, the comprehensive destruction of the coring bit required further remedial operations to remove junk and huge volumes of accumulated drill cuttings. Hole-cleaning operations using junk baskets were successful, and they recovered large irregular samples that document a hitherto unseen sequence of evolving geological conditions and the intimate coupling between temporally and spatially intercalated intrusive, hydrothermal, contact-metamorphic, partial melting, and retrogressive processes. Hole 1256D is now clean of junk, and it has been thoroughly cleared of the drill cuttings that hampered operations during this and previous expeditions. At the end of Expedition 335, we briefly resumed coring before undertaking cementing operations to secure problematic intervals. To ensure the greatest scientific return from the huge efforts to stabilize this primary ocean lithosphere reference site, it would be prudent to resume the deepening of Hole 1256D in the nearest possible future while it is open to full depth. doi:<a href="http://dx.doi.org/10.2204/iodp.sd.13.04.2011" target="_blank">10.2204/iodp.sd.13.04.2011</a>

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North Atlantic Paleoceanography from Integrated Ocean Drilling Program Expeditions (2003–2013)

Earth and Life Processes Discovered from Subseafloor Environments - A Decade of Science Achieved by the Integrated Ocean Drilling Program (IODP) - Developments in Marine Geology ◽

10.1016/b978-0-444-62617-2.00014-1 ◽

2014 ◽

pp. 359-393

Author(s):

James E.T. Channell ◽

David A. Hodell

Keyword(s):

North Atlantic ◽

Ocean Drilling Program ◽

Ocean Drilling ◽

Integrated Ocean Drilling Program

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The magnetization of oceanic crust: contribution to knowledge from the Troodos, Cyprus, ophiolite

Canadian Journal of Earth Sciences ◽

10.1139/e91-161 ◽

1991 ◽

Vol 28 (11) ◽

pp. 1812-1826 ◽

Cited By ~ 6

Author(s):

James M. Hall ◽

Charles C. Walls ◽

Jing-Sui Yang ◽

S. Lata Hall ◽

Abdul Razzak Bakor

Keyword(s):

Lower Limit ◽

Oceanic Crust ◽

Drill Hole ◽

Extensive Study ◽

Drill Core ◽

Average Depth ◽

Ocean Drilling Program ◽

Ocean Drilling ◽

Core Samples ◽

Key Questions

An extensive study of a segment of the Troodos, Cyprus, ophiolite using both outcrop and drill-core samples, and extending from the sediment–extrusive interface through sheeted dikes to cumulate ultramafics, has allowed a number of key questions regarding the magnetization of oceanic crust to be addressed. These include the number of strongly magnetized intervals with depth, their lateral variability and controls on their occurrence. Comparison has also been made with the section in Ocean Drilling Program (ODP) hole 504B, and a reinterpretation of its constructional setting is offered.Two strongly magnetized intervals occur in the area studied. The upper is in the extrusive sequence, extends on average from 0.2 to 0.6 km depth, and has a thickness of ~0.4 km. Here magnetization is dominated by remanence. The lower interval extends from the lowest level at which flows occur with dikes (average depth = 0.9 km) into the Sheeted Complex (average depth = 1.2 km) and has a thickness of 0.3 km. Here magnetization is dominantly induced. No other strongly magnetized intervals occur in the section. The extent of dike intrusion is closely related to the position of the lower limit of the high-remanence layer and to the occurrence of the high induced magnetization layer. In both cases the replacement of primary magnetite, which can carry a strong remanence, by magnetically soft secondary magnetite appears to be the controlling process.Comparison of the Troodos and hole 504B magnetization profiles shows close similarity in the upper, remanence-dominated magnetic interval. The absence of the deeper interval of high induced magnetization in the hole 504B profile is interpreted as meaning that sheeted dikes have not been penetrated by the drill hole.

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High resolution CO2 record of the great Plio-Pleistocene glaciations using boron isotopes

10.5194/egusphere-egu2020-10925 ◽

2020 ◽

Author(s):

Rachel Brown ◽

Thomas Chalk ◽

Paul Wilson ◽

Eelco Rohling ◽

Gavin Foster

Keyword(s):

High Resolution ◽

Northern Hemisphere ◽

Large Scale ◽

Boron Isotope ◽

Ocean Drilling Program ◽

Proxy Record ◽

Ocean Drilling ◽

Integrated Ocean Drilling Program ◽

Great Transition ◽

Adequate Test

The intensification of Northern Hemisphere glaciation (iNHG) at 3.4-2.5 million years ago (Ma) represents the last great transition in Cenozoic climate state with the development of large scale ice sheets in the Northern Hemisphere that waxed and waned with changes in insolation. Declining atmospheric CO2 levels are widely suggested to have been the main cause of iNHG but the CO2 proxy record is too poorly resolved to provide an adequate test of this hypothesis. The boron isotope-pH proxy, in particular, has shown promise when it comes to accurately estimating past CO2 concentrations and is very good at reconstructing relative changes in CO2 on orbital timescales. Here we present a new orbitally resolved record of atmospheric CO2 (1 sample per 3 kyr) change from Integrated Ocean Drilling Program Site 999 (12.74&#730;N, -78.74 &#730;E) spanning ~2.6&#8211;2.4&#160;Ma based on the boron isotope (&#948;11B) composition of planktic foraminiferal calcite, Globingerinoides ruber (senso stricto, white). &#160;We find that &#948;11B values of G. ruber show clear glacial-interglacial cycles with a magnitude that is similar to those of the Mid-Pleistocene at the same site and elsewhere.&#160; This new high-resolution view of CO2 during the first large glacial events of the Pleistocene confirms the importance of CO2 in amplifying orbital forcing of climate and offers new insights into the mechanistic drivers of natural CO2 change.&#160;

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