(Table 1) Paleomagnetic properties of specimens from DSDP Holes 69-504B and 70-504B

Paleomagnetic and rock magnetic measurements of basalt specimens from DSDP Hole 504B, associated with the Costa Rica Rift, have a mean natural remanence intensity (Jn) between 5 and 10 x 10**-3 gauss, consistent with the presence of a magnetized layer that is 0.5 to 1 km thick, which produces the observed magnetic anomalies. A mean Koenigsberger ratio (Qn) greater than 10 indicates that the remanence dominates the magnetic signal of the drilled section. The susceptibility (x) increases with depth, and the median demagnetizing field (MDF) decreases with increasing depth in Hole 504B, congruent with the downhole increase in the relative abundance of massive flow units. Hole 504B is composed of at least 12 units with distinct stable average inclinations (Is), which probably represent extrusion at times of different geomagnetic field directions and possibly also the effects of faulting. The thickness of basalt associated with these inclination units varies from less than 9 meters to possibly as much as 160 meters. Two relatively thick magnetic units (40 m and 45 m, separated by 100 m) have anomalously high Is values of -53° and -63°, in contrast with the near zero inclinations expected for the equatorial latitude of Site 504. For this reason and because the average inclination of all the magnetic units is skewed to a negative value, it might be that the entire section at Hole 504B was tilted by approximately 30°.

(Table 1) Sulfur isotopes and description of anhydrite in DSDP Holes 70-504B and 83-504B

Anhydrite occurs in veins in hydrothermally altered basalts recovered from Hole 504B during Leg 83 of the Deep Sea Drilling Project. Sulfur isotopic data indicate that the anhydrites formed from fluids with sulfur isotopic compositions similar to seawater sulfate. Anhydrite probably formed as a pulse of relatively unreacted seawater was heated when it entered a relatively hot hydrothermal system containing evolved fluids. Reheating and continued evolution of the system followed anhydrite deposition. Preservation of anhydrite in Hole 504B was probably favored by the high temperatures and by the low permeability that resulted from the sealing of cracks with secondary minerals. Evidence also indicates that anhydrite was partly replaced by laumontite and prehnite at relatively high temperatures, and possibly by calcite at lower temperatures.

Performance characteristics of automotive engines in the United States. First series-- report no. 14. 1975 Mazda Rotary 70 CID (1.1 liters), 4V. Interim report.

Transportation Systems Center, Cambridge, Mass.

Notturno : per orchestra, op. 70, n. 1 /

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Digest of the Lawyers reports annotated, volumes 1-70 ... with full index to annotation.

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