Rock- and Paleomagnetism of Deep Sea Drilling Project Leg 54 BasaltsEast Pacific Rise and Galapagos Rift

Petersen, N.; Roggenthen, William

doi:10.2973/dsdp.proc.54.140.1980

Cited by 10 publications

(11 citation statements)

References 12 publications

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“…The high saturation magnetization (J s ) of Holes 506G, 507B, and 508B suggests that the content of magnetic minerals is high. Data from Sites 424 and 425, which are located on an area of high heat flow, show high J s (Petersen and Roggenthen, 1980). On the other hand, the J s of samples from Hole 510, which was located on an area of normal heat flow, has a wide range and a lower mean J s value, suggesting one of the following: (1) that the content of magnetic minerals is very similar to that of the high J s holes, but that weathering has decreased the J s values or (2) that the concentration of magnetic minerals is normal and similar in content to that of other submarine basalts.…”

Section: Discussionmentioning

confidence: 99%

“…It is well known that the x-value of titanomagnetite in submarine basalts has limited variation and that it is about 0.6 (e.g., Johnson and Hall, 1978;Ryall and Hall, 1980;Petersen and Roggenthen, 1980). Although there are not enough samples to discuss the x-value of titanomagnetite, some data do show a different value from normal submarine basalts.…”

Section: Discussionmentioning

confidence: 99%

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Magnetic Properties of Basalts from the Galapagos Spreading Center: A Correlation between Basalts from the Galapagos Rift and the Costa Rica Rift

Furuta¹

1983

Initial Reports of the Deep Sea Drilling Project

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Magnetic Properties of Basalts from the Galapagos Spreading Center: A Correlation between Basalts from the Galapagos Rift and the Costa Rica Rift

Furuta¹

1983

Initial Reports of the Deep Sea Drilling Project

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“…The inclinations, which during the latest Eocene and early Oligocene are expected to reflect a southerly latitude of some 7 to 10°, do not allow the identification of polarity sequences. The NRM 0 intensities of the six basalt samples measured have a mean of 3.7 ± 2.7 × 10~4 G, which is typical of such material (Petersen and Roggenthen, 1980). The magnetostratigraphies developed for the uppermost parts of Holes 573 and 573A are shown in Figure 6.…”

Section: Site 573mentioning

confidence: 91%

Paleomagnetism of Deep Sea Drilling Project Leg 85 Sediments: Neogene Magnetostratigraphy and Tectonic History of the Central Equatorial Pacific

Weinreich¹,

Theyer²

1985

Initial Reports of the Deep Sea Drilling Project

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On Leg 85, 16 holes were cored at five sites. Thirteen of the holes were cored with the hydraulic piston corer (HPC) or the variable-length hydraulic piston corer (VLHPC) or both; the remainder were rotary drilled. Partially duplicating stratigraphic sections were successfully recovered by hydraulic piston coring at Sites 572 to 575. Sub-bottom penetration was deepest (about 210 m) at HPC Hole 575A, which bottomed in lower Miocene sediments. Penetration by hydraulic piston coring was limited at all sites not by the failure of the corer to stroke out but by the excessive force (overpull) necessary to retrieve the core barrel from the hole. The sediments recovered are relatively uniform siliceous-calcareous oozes to calcareous ooze-chalks. Paleomagnetic measurements were made at all stratigraphic levels, but magnetostratigraphic sequences could be resolved only for the Pleistocene-Pliocene and for brief upper, middle, and lower Miocene sections.In the younger and less consolidated sediments, the declination often shows large-scale azimuthal rotations downcore. These smooth trends vary from core to core, indicating either rotation between the sediment and the core liner or the rotation of the core barrel during the coring or retrieval process. Thus, azimuthal orientation of the samples was impossible even though a Kuster azimuthal orientation tool was used during the hydraulic piston coring.At all sites, the downhole shift from mainly siliceous to mainly calcareous ooze-chalk coincided with a decrease in NRM intensity of at least one order of magnitude, to 1.0 × 10 ~8 ò. Diagenesis is the probable reason for this behavior, although the dilution of magnetic carriers as the result of higher accumulation rates may also be a factor. A tectonic analysis using data from samples with stable remanence indicates a northward plate motion of about 0.3°/m.y. during the last 18 m.y., a rate that agrees with most previous reconstructions of Pacific Plate motion.

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“…From their data they derived a time constant of T = 5 x 10 7 yr. Using a much larger number of data from various DSDP drill holes, Petersen and Roggenthen (1980) (Fig. 6A).…”

Section: Age-estimate Of 648b Hole Basaltsmentioning

confidence: 99%

Titanomagnetite Oxidation State and Age of Basalts from ODP Hole 648B

Petersen¹,

Vali²

1990

Proceedings of the Ocean Drilling Program

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The titanomagnetite oxidation state of "zero age" ocean floor basalts was investigated. For this purpose the oxidation parameter, z, of Hole 648B basalts was determined by SEM observation of "shrinkage cracks" in individual titanomagnetite grains and by Curie temperature measurements. A mean z-value of 0.1 has been deduced for the Hole 648B basalts.Assuming a linear relationship between titanomagnetite low-temperature oxidation state and age of the oceanic basalt, an age of 0.7 m.y. is deduced for Hole 648B.

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Rock- and Paleomagnetism of Deep Sea Drilling Project Leg 54 BasaltsEast Pacific Rise and Galapagos Rift

Cited by 10 publications

References 12 publications

Magnetic Properties of Basalts from the Galapagos Spreading Center: A Correlation between Basalts from the Galapagos Rift and the Costa Rica Rift

Magnetic Properties of Basalts from the Galapagos Spreading Center: A Correlation between Basalts from the Galapagos Rift and the Costa Rica Rift

Paleomagnetism of Deep Sea Drilling Project Leg 85 Sediments: Neogene Magnetostratigraphy and Tectonic History of the Central Equatorial Pacific

Titanomagnetite Oxidation State and Age of Basalts from ODP Hole 648B

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Rock- and Paleomagnetism of Deep Sea Drilling Project Leg 54 BasaltsEast Pacific Rise and Galapagos Rift

Cited by 10 publications

References 12 publications

Magnetic Properties of Basalts from the Galapagos Spreading Center: A Correlation between Basalts from the Galapagos Rift and the Costa Rica Rift

Magnetic Properties of Basalts from the Galapagos Spreading Center: A Correlation between Basalts from the Galapagos Rift and the Costa Rica Rift

Paleomagnetism of Deep Sea Drilling Project Leg 85 Sediments: Neogene Magnetostratigraphy and Tectonic History of the Central Equatorial Pacific

Titanomagnetite Oxidation State and Age of Basalts from ODP Hole 648B

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Rock- and Paleomagnetism of Deep Sea Drilling Project Leg 54 BasaltsEast Pacific Rise and Galapagos Rift