Paleomagneitc of early Cretaceous sediments from the western Central Atlantic

Drilling at Sites 534 and 603 of the Deep Sea Drilling Project recovered thick sections of Berriasian through Aptian white limestones to dark gray marls, interbedded with claystone and clastic turbidites. Progressive thermal demagnetization removed a normal-polarity overprint carried by goethite and/or pyrrhotite. The resulting characteristic magnetization is carried predominantly by magnetite. Directions and reliability of characteristic magnetization of each sample were computed by using least squares line-fits of magnetization vectors. The corrected true mean inclinations of the sites suggest that the western North Atlantic underwent approximately 6° of steady southward motion between the Berriasian and Aptian stages. The patterns of magnetic polarity of the two sites, when plotted on stratigraphic columns of the pelagic sediments without turbidite beds, display a fairly consistent magnetostratigraphy through most of the Hauterivian-Barremian interval, using dinoflagellate and nannofossil events and facies changes in pelagic sediment as controls on the correlations. The composite magnetostratigraphy appears to include most of the features of the M-sequence block model of magnetic anomalies from Ml to Ml ON (Barremian-Hauterivian) and from M16 to M23 (Berriasian-Tithonian). The Valanginian magnetostratigraphy of the sites does not exhibit reversed polarity intervals corresponding to Ml 1 to M13 of the M-sequence model; this may be the result of poor magnetization, of a major unrecognized hiatus in the early to middle Valanginian in the western North Atlantic, or of an error in the standard block model. Based on these tentative polarity-zone correlations, the Hauterivian/Barremian boundary occurs in or near the reversed-polarity Chron M7 or M5, depending upon whether the dinoflagellate or nannofossil zonation, respectively, is used; the Valanginian/Hauterivian boundary, as defined by the dinoflagellate zonation, is near reversed-polarity Chron M10N.

Late Eocene to Recent deep-sea benthic foraminifera from the Central equatorial Pacific Ocean

Benthic foraminifers were studied in upper Eocene to Recent core-catcher samples from DSDP Sites 573, 574, and 575. The sites are on a north-south transect from the equator to about 05°N at about 133°W, water depth 4300 to 4600 m. At Site 574 additional samples were used to study the Eocene/Oligocene boundary in detail. About 200 specimens were counted per sample. The fauna is highly diverse (about 50 to 70 species per sample) and is of low dominance. The diversity is not related to age or sub-bottom depth. Many species are cosmopolitan and probably have wide environmental tolerances. Fluctuations in frequency of some taxa (e.g., Nuttallides umbonifera, Epistominella exigua, and Uvigerina spp.) cannot be correlated from one site to another. Several common species (e.g. Oridorsalis umbonatus and Globocassidulina subglobosa) range from late Eocene to Recent. First and last appearances are generally difficult to define precisely because many species are rare. For some species these datums differ from one site to another, but several datum levels are within 1 m.y. at all sites. First and last appearances are most numerous in two intervals, the late Eocene to early Oligocene (about 32 to 37 Ma) and the early to middle Miocene (about 13 to 18.5 Ma). Isotopic events occur within each of these periods of benthic faunal change, but the isotopic events have a shorter duration and start after the initiation of the changes in the fauna. Changes in deep-sea benthic faunal composition are not directly related to short-term oceanographic changes as expressed in isotopic records.

Foreign aid : questions on the Central American regional program need to be resolved : report to the Honorable Patrick Leahy, United States Senate /

"B-221422"--P. [1].

Central America aid : status of the Trade Credit Insurance Program : fact sheet for the Honorable Patrick Leahy, U.S. Senate /

"B-221422"--1st. prelim. p.

Central American refugees : regional conditions and prospects and potential impact on the United States : report to the Congress of the United States /

Item 546-D (microfiche)

Central America : conditions of refugees and displaced persons : report to congressional requesters /

"B-233434"--p.[1]

Central America : conditions of Guatemalan refugees and displaced persons : report to congressional requesters /

Cover title.

Refugees and U.S. asylum seekers from Central America : statement of Nancy R. Kingsbury, Director, Foreign Economic Assistance Issues, National Security and International Affairs Division; before the Subcommittee on Immigration, Refugees, and International Law, Committee on the Judiciary, House of Representatives.

"For release ... March 9, 1989."

National Highway Traffic Safety Administration's 1980-81 workshop series on alcohol and occupant restraints - central states. Final report.

National Highway Traffic Safety Administration, Office of Driver and Pedestrian Programs, Washington, D.C.

Biodetoxification of RCRA, Superfund, and other toxic wastes using resources of central wastewater treatment plants.

Mode of access: Internet.

Convention between the United Kingdom and France respecting commercial relations between France and the British Protectorates of East Africa, Central Africa, and Uganda.

"Signed at London, February 23, 1903. (Ratifications exchanged at London, March 27, 1905.)"

National training course, emergency medical technician - paramedic. Instructor's lesson plans. Module VII: central nervous system.

Mode of access: Internet.

Photovoltaic central power plants : some new evaluations on the basis of revised insolation data /

"July 1978."

Central receiver solar thermal system : phase 1 /

"Work Performed Under Contract No. EY-76-C-03-1108."

Laboratory studies on the effects of laboratory simulated earthquake loadings on cohesive soil strength, San Luis Dam and Canal, San Luis Unit Central Valley Project, California.

"Report no. EM-715."