Annotated record of the detailed examination of Mn deposits from DSDP Site 38, Leg 5 (Cores 5-38-6)

The nonfossiliferous nature of most of the thin sediment sequence at Site 37 had provided little biostratigraphic information for the northern end of the proposed section of sites along 140°W longitude. In an attempt to provide a biostratigraphically more meaningful hole as the high latitude terminus of the meridional section, an additional site (Site 38) was drilled between the Mendocino and Pioneer Fracture Zones.

Annotated record of the detailed examination of Mn deposits from JOIDES Preliminary Cruise with M/V Caldrill I on the Blake Plateau

In May 1964 the Institute of Marine Science (University of Miami), Scripps Institution of Oceanography (University of California), Woods Hole Oceanographic Institution, and Lamont Geological Observatory (Columbia University) joined in the establishment of the JOINT OCEANOGRAPHIC INSTITUTIONS DEEP EARTH SAMPLING (JOIDES) program. The long range purpose of this organization is to obtain continuous core samples of the entire sedimentary column from the floors of the oceans. It was decided that initial efforts would be limited to water depths of less than 1000 fathoms (6000 feet), and tentative locations were selected for drilling operations off the eastern, western and Gulf coasts of the United States. Near the end of December 1964 it was found that the M/V Caldrill I, a drilling vessel capable of working to depths of 6000 feet, was to engage in drilling operations on the Grand Banks of Newfoundland during the summer of 1965 for the Pan American Petroleum Corporation. Thus it was agreed to organize a drilling program along the track of Caldrill between California and the Grand Banks. Selection was made of an area on the continental shelf and the Blake Plateau off Jacksonville, Florida. Based upon many previous geological and geophysical investigations by the participating laboratories, a considerable body of knowledge had been gained about this region of the continental-oceanic border. For this initial program of JOIDES, the Lamont Geological Observatory was chosen as the operating institution with J. L. Worzel as principal investigator, and C. L. Drake and H. A. Gibbon as program planners.

Annotated record of the detailed examination of Mn deposits from Hudson-70, Phase VII cruise (CNAV Endeavour) stations

A geophysical survey was conducted off Vancouver and Queen Charlotte Islands over a four-week period (July 12 to August 5, 1970) as part of HUDSON-70 expedition. The HUDSON-70 expedition was organized as part of the Canadian contribution to the International Decade of Oceanographic Exploration. The geophysical survey was conducted to study the subsurface structure across the continental margin off the British Columbia coast and in the deep ocean basins. The present report contains descriptions of the various measurements made during this cruise and the data collected.

Annotated record of Mn deposits from R/V Anton Bruun, Cruise 17 Expedition stations

Station 678E (29°22'S. latitude, 80WW. longitude) is roughly midway between San Felix and Juan Fernandez Islands, and approximately 700 km west of the coast of Chile. The sample at Station 678E was collected in a Riedl Dredge with a finer net sewn into the cod end of the 500 JJ mesh bag. The change in depth during the dredging operation indicated a rather rapid shelving. The bottom was a red clay with some volcanic ash. Manganese nodules were present (rock dredge sample).

Annotated record of the detailed examination of Mn deposits from R/V Moana Wave Cruise Mn-74-01 stations

Cruise MN-74-01 of the R/V Moana Wave was the first part of the field work of the NSF-IDOE Inter-University Ferromanganese Research Program in 1974. This program was designed to investigate the origin, growth, and distribution of copper/nickel-rich manganese nodules in the Pacific Ocean. The field effort was designed to satisfy sample requirements of the 15 principal investigators, while increasing general knowledge of the copper/nickel-rich nodule deposits of the equatorial Pacific. This report is the first of a series of cruise reports designed to assist sample requests for documented nodules, sediment, and water samples so the laboratory results can be realistically compared and related to the environment of nodule growth.

Annotated record of the detailed examination of Mn deposits from the R/V Argo ZETES Expedition in the Pacific Ocean

The cores and dredges described are taken during the R/V Argo ZETES Expedition from March until August 1966 by the Scripps Institute of Oceanography. A total of 53 cores and dredges were recovered and are available at Scripps Institute of Oceanography for sampling and study.

Annotated record of the detailed examination of Mn deposits from DSDP Site 24, Leg 4 (Core 4-24-1)

The drilling objectives at this site were to complete the cored section begun at Site 23 in accordance with the recommendations of the JOIDES Atlantic Advisory Panel, presented in the Site 23 report. The location coincides with a position on the southeastern side of the elevated portion of basement in this area.

Annotated record of the detailed examination of Mn deposits from DSDP Site, Leg 4 (Cores 4-27-1 and 4-27A-1)

The northern margin of the Demerara Abyssal Plain is bordered by a low ESE-WNW trending rise known as the Barracuda Ridge. North of South America, the eastern margin of the Demerara Abyssal Plain is formed by the Barbados Ridge. An extensive sedimentary section of the Barbados Ridge is exposed on the island of Barbados and consists of a series of radiolarian to planktonic foraminiferal and calcareous nannofossil biogenic sediments interlayered with ash beds. To determine the nature of the sediments and "basement," Site 27 was selected on the northern margin of the Demerara Abyssal Plain, south of the Barracuda Ridge.

Annotated record of the detailed examination of Mn deposits from DSDP Site 25, Leg 4 (Core 4-25A-1)

At the Leg 4 pre-cruise meeting in Miami, Florida, in January 1969, the Ridge site was proposed as an additional site to be investigated, if possible. Since the water depth and sediment thickness at this site were both minimal (2000 meters and less than 100 meters, respectively) and the location was not far from the track between initially planned sites, the shipboard party decided, upon completion of work at Site 24, to make a 24-hour drilling effort on the North Brazilian Ridge. The drilling objectives at this location were to sample and date the sediments atop the Ridge crest and to determine the nature, age and origin of the consolidated material beneath the thin mantle of sediment.

Annotated record of the detailed examination of Mn deposits from DSDP Site 26, Leg 4 (Core 4-26-1)

Site 26 was selected on the crest of the Mid-Atlantic Ridge between 15°N and 5°S is offset to the east nearly 4000 kilometers through a series of fracture zones. One of the most prominent of these is the Vema Fracture Zone, a narrow east-west trending trough which cuts through the Mid-Atlantic Ridge at latitude 11°N.

Annotated record of the detailed examination of Mn deposits from DSDP Site 29, Leg 4 (Hole 4-29B)

The southern Caribbean basins are thought to be part of a relatively old and geologically stable crustal plate. Although surrounded by belts of high earthquake activity, the central Caribbean is seismically quiet. The region also constitutes a quiet magnetic zone and appears to have resisted all of the surrounding forces related to ocean floor spreading. In addition to providing considerable information on the general geologic history of the Caribbean region, paleontologic studies on cores at Site 29 were expected to provide valuable data on phylogenetic trends within the planktonic foraminifera and calcareous nannoplankton, furnishing more accurate criteria for intercontinental stratigraphic correlation. The work reported here is a biostratigraphic summary of available samples. only the most important and biostratigraphically significant components of the faunas have been noted. No attempt has been made to give an exhaustive faunal analysis of the samples seen.

Heavy Minerals in Soils from the Athabasca Basin and the Implications for Exploration Geochemistry of Uranium Deposits at Depth

The Centennial deposit is a high grade (~8% U3O8), deeply buried (~950m), unconformity-related U deposit located in the south-central region of the Athabasca Basin in northern Saskatchewan, Canada. The mineral chemistry of fine fractions (<63 μm) of soils from grids above the Centennial deposit were examined to understand possible controls on the geochemistry and radiogenic 207Pb/206Pb ratios measured in the clay-size (<2 μm) fractions used for exploration. Soil samples distal and proximal to the deposit projection to the surface and geophysically defined structures were selected. Mineral abundances were determined using the scanning electron microscope and Mineral Liberation Analysis. Zircon was the only U-rich mineral identified with modal abundances >0.02% by weight. Monazite, which can be U-rich, was identified, but not in significant abundances. The source of the zircon and other heavy minerals is interpreted to be from sub-cropping sources that are >100 km up-ice from Centennial. Trace element analysis using laser ablation inductively coupled plasma mass spectrometry of hydroseparated zircon grains indicate that zircon abundances and zircon Pb concentrations in surficial samples have minimal effect on the radiogenic 207Pb/206Pb ratios in the clay-fraction of the samples, with the dominant source of radiogenic Pb being clay mineral surfaces that trapped Pb during secondary dispersion from the Centennial uranium deposit through faults and fractures to the surface. The REE patterns indicate HREE enrichment in the clay-fractions of samples that have higher abundances of zircon in the <20 μm fraction. Immobile elements such as HREE that are concentrated in zircon can be used as indicators of radiogenic Pb being sourced from minerals at the surface rather than being sourced from secondary dispersion from deeply buried U deposits.

Upper-Pleistocene terrace deposits in Mediterranean climate: geomorphological and source-rock control on mineral and geochemical signatures (Betic Cordillera, SE Spain)

Mineral and chemical composition of alluvial Upper-Pleistocene deposits from the Alto Guadalquivir Basin (SE Spain) were studied as a tool to identify sedimentary and geomorphological processes controlling its formation. Sediments located upstream, in the north-eastern sector of the basin, are rich in dolomite, illite, MgO and KB2BO. Downstream, sediments at the sequence base are enriched in calcite, smectite and CaO, whereas the upper sediments have similar features to those from upstream. Elevated rare-earth elements (REE) values can be related to low carbonate content in the sediments and the increase of silicate material produced and concentrated during soil formation processes in the neighbouring source areas. Two mineralogical and geochemical signatures related to different sediment source areas were identified. Basal levels were deposited during a predominantly erosive initial stage, and are mainly composed of calcite and smectite materials enriched in REE coming from Neogene marls and limestones. Then the deposition of the upper levels of the alluvial sequences, made of dolomite and illitic materials depleted in REE coming from the surrounding Sierra de Cazorla area took place during a less erosive later stage of the fluvial system. Such modification was responsible of the change in the mineralogical and geochemical composition of the alluvial sediments.