The late Pliocene pollen record of ODP Site 108-658 off Cape Blanc, Atlantic Ocean

A 200 m long marine pollen record from ODP Site 658 (21°N, 19°W) reveals cyclic fluctuations in vegetation and continental climate in northwestern Africa from 3.7 to 1.7 Ma. These cycles parallel oxygen isotope stages. Prior to 3.5 Ma, the distribution of tropical forests and mangrove swamps reached Cape Blanc, 5°N of the present distribution. Between 3.5 and 2.6 Ma, forests occurred at this latitude during irregular intervals and nearly disappeared afterwards. Likewise, a Saharan paleoriver flowed continuously until isotope Stage 134 (3.35 Ma). When river discharge ceased, wind transport of pollen grains prevailed over fluvial transport. Pollen indicators of trade winds gradually increased between 3.3 and 2.5 Ma. A strong aridification of the climate of northwestern Africa occurred during isotope Stage 130 (3.26 Ma). Afterwards, humid conditions reestablised followed by another aridification around 2.7 Ma. Repetitive latitudinal shifts of vegetation zones ranging from wooded savanna to desert flora dominated for the first time between between 2.6 and 2.4 Ma as a response to the glacial stages 104, 100 and 98. Although climatic conditions, recorded in the Pliocene, were not as dry as those of the middle and Late Pleistocene, latitudinal vegetation shifts near the end of the Pliocene resembled those of the interglacial-glacial cycles of the Brunhes chron.

Changes in the vegetation and trade winds in equatorial Northwest Africa 140,000-70,000 yr B.P., as deduced from two marine pollen records

The deep-sea cores M 16415-2 and M 16416-2 at about 9°N off Sierra Leone were analysed palynologically for the time interval 140,000-70,000 yr B.P. Results were presented in absolute (pollen concentration and pollen influx) and relative diagrams (pollen percentage). In a previous study it was evidenced that in northwest Africa pollen is mainly transported to the Atlantic by wind, so that the efficiency of aeolian pollen transport (pollen flux) could be used to evaluate changes in the intensity of the northeast trade winds. The glacial episodes (represented by the oxygen isotope stages 6 and 4) are characterized by strong northeast trade winds, whereas the last interglacial (stage 5) is characterized by weak trade winds. The pollen influx diagram shows that the intensity of the trade winds increased slightly during the relatively cool intervals of stage 5 (viz. 5.4 and 5.2). Tropical forest had maximally expanded around 124,000 yr B.P. (stage 5.5), around 98,000 yr B.P. (transition of stage 5.3 to 5.2), and around 70,000 yr B.P. (first part of stage 4): an increasing delay of the response of tropical forest to global intervals with maximum temperature is apparent during the last interglacial. As tropical forests need continuous humidity, the record of tropical forest monitors changes in climatic humidity south of the Sahara. During the last interglacial, the southern boundary of the Sahara shifted only little: expansions and contractions of the tropical forest area are correlated with contra-oscillations of the grass-dominated savanna zone. Great latitudinal shifts of the desert savanna boundary, on the contrary, occurred during the penultimate glacial interglacial transition (around 128,000 yr B.P.) to the north, and during the last interglacial-glacial transition (around 65,000 yr B.P.) to the south.

Geochemistry of sediments from the upwelling off Morocco

The high-productive upwelling area off Morocco is part of one of the four major trade-wind driven continental margin upwelling zones in the world oceans. While coastal upwelling occurs mostly on the shelf, biogenic particles derived from upwelling are deposited mostly at the upper continental slope. Nutrient-rich coastal water is transported within the Cape Ghir filament region at 30°N up to several hundreds of kilometers offshore. Both upwelling intensity and filament activity are dependent on the strength of the summer Trades. This study is aimed to reconstruct changes in trade wind intensity over the last 250,000 years by the analysis of the productivity signal contained in the sedimentary biogenic particles of the continental slope and beneath the Cape Ghir filament. Detailed geochemical and geophysical analyses (TOC, carbonate, C/N, delta13Corg, delta15N, delta13C of benthic foraminifera, delta18O of benthic and planktic foraminifera, magnetic susceptibility) have been carried out at two sites on the upper continental slope and one site located further offshore influenced by the Cape Ghir filament. A second offshore site south of the filament was analyzed (TOC, magnetic susceptibility) to distinguish the productivity signal related to the filament signal from the general offshore variability. Higher productivity during glacial times was observed at all four sites. However, the variability of productivity during glacial times was remarkably different at the filament-influenced site compared to the upwelling-influenced continental slope sites. In addition to climate-related changes in upwelling intensity, zonal shifts of the upwelling area due to sea-level changes have impacted the sedimentary productivity record, especially at the continental slope sites. By comparison with other proxies related to the strength and direction of the prevailing winds (Si/Al ratio as grain-size indicator, pollen) the productivity record at the filament-influenced site reflects mainly changes in trade-wind intensity. Our reconstruction reveals that especially during glacial times trade-wind intensity was increased and showed a strong variability with frequencies related to precession.

Trade with Cuba. Hearings before the Committee on Interstate and Foreign Commerce, House of Representatives, Eighty-seventh Congress, first session, on H. R. 8465, a bill to prohibit the shipment in interstate or foreign commerce of articles imported into the United States from Cuba, and for other purposes (and identical bills); H.R. 8866, a bill tp prohibit the shipment in interstate or foreign commerce of articles imported into the United States from Cuba, to provide penalties for such shipment, and for other purposes. August 29 and September 1, 1961.

Mode of access: Internet.

Virgin Islands trade study : an economic analysis /

Oct. 1979.

Trade preferences: Latin America and the Caribbean.

Includes bibliographical references.

World trade information service.

Issued in pts.: 1954- pt. 1. Economic reports; pt. 2. Operation reports; pt. 3. Statistical reports; pt. 4. Utilities abroad; and 1955- pt. 5. Fairs and exhibitions.

The Eurocurrency market control act of 1979 : hearings before the Subcommittee on Domestic Monetary Policy and the Subcommittee on International Trade, Investment, and Monetary Policy of the Committee on Banking, Finance, and Urban Affairs, House of Representatives, Ninety-sixth Congress, first session, on H.R. 3962 ... June 26, 27, and July 12, 1979.

"Serial no. 96-23."

Amending the Export-import bank act of 1945 with respect to credit to Communist countries : hearings before the Subcommittee on International Trade, Investment, and Monetary Policy of the Committee on Banking, Finance, and Urban Affairs, House of Representatives, Ninety-sixth Congress, first session, on H.R. 1908 ... July 23 and 24, 1979.

"Serial no. 96-24."

Monetary policy : goals and conduct for the 1980's : hearings before the Subcommittee on Domestic Monetary Policy and the Subcommittee on International Trade, Investment, and Monetary Policy of the Committee on Banking, Finance, and Urban Affairs, House of Representatives, Ninety-sixth Congress, first session, November 13, 27, and December 4, 1979.

Mode of access: Internet.

Report of Joint committee of enquiry into the Anglo-Argentine meat trade ...

George Schuster, chairman.

Future developments in the food industry and their implications for the Federal Trade Commission /

"July 1980."

The development and structure of the U.S. electric lamp industry : staff report of the Federal Trade Commission /

Cover title: Staff report on the development and structure of the U.S. electric lamp industry.

Advertising for over-the-counter drugs : public record 215-51, 16 CFR part 450 : report of the presiding officer on proposed trade regulation rule /

Cover title.

Appendices C through F to the Hearing aid industry staff report : final report to the Federal Trade Commission and proposed trade regulation rule (16 CFR, part 440) /

Mode of access: Internet.