Annotated record of the detailed examination of Mn deposits from SOMIRMAS cruise stations

The cores and dredges described at this site were taken on the SOMIRMAS cruise from 5 July to 14 August 1990 by the MusÈum National d'Histoire Naturelle from the R/V Marion Dufresne. A total of 30 cores and dredges were recovered and are available at MNHN for sampling and study.

Annotated record of the detailed examination of Mn deposits from SEYMAMA-SHIVA cruise stations

The cores and dredges described at this site were taken on the SEYMAMA-SHIVA cruise from 17 August to 14 September 1990 by the MusÈum National d'Histoire Naturelle from the R/V Marion Dufresne. A total of 33 cores and dredges were recovered and are available at MNHN for sampling and study.

(Table, page 13-59), Annotated record of the detailed examination of Mn deposits from Amphitrite Expedition stations

The cores described in this report were taken on AMPHITRITE Expedition in Decenber 1963 - February 1964 by Scripps Institution of Oceanography from, the R/V Argo. A total of 148 cores were recovered and are available at Scripps for sampling and study. The coring sites, all in the tropical central Pacific. The AMPHITRITE cores are here briefly described to identify visually distinct units based on lithology, color, texture, or other characteristic unique to an interval of sediment. For determination of lithology, the slides prepared from samples of the cores were examined microscopically in conjuction with the visual examination.

Annotated record of the detailed examination of Mn deposits in a core from R/V Hakuho Maru Cruise KH-74-4 station

A sediment core obtained from the northeastern Philippine Sea Basin was analyzed for 232Th, 230Th, 226Ra and 210Pb. Three sheets of Ferro-manganese oxide in a matrix of red clay were included in the 73 m core. Although the concentration of 232Th of land origin is normal as compared with that of the usual red clay or of the sediment obtained at the neighboring station, the concentration of radiogenic 230Th is extremely low and does not decrease with increasing depth. The radioactivity of rather soluble 226Ra at the station is not less than that of 230Th in the surface sediment, showing a tendency different from that observed in usual cores. Some enrichment in the comparatively short-lived 210Pb activity relative to 226Ra activity was found in the top sediment and in the first ferro-manganese sheet at the station. If the excess 210Pb in the ferro-manganese sheet is not due to contamination of the surface sediment, lead should migrate through the sheet. These facts suggest that the core has not been accumulating during the past few hundred thousand years or more.

Ash layers, hyaloclastite, and alteration of basaltic glass at DSDP Leg 65 Holes

Three types of tephra deposits were recovered on Leg 65 of the Deep Sea Drilling Project (DSDP) from three drill sites at the mouth of the Gulf of California: (1) a series of white ash layers at Sites 483, 484, and 485; (2) a layer of plagioclase- phyric sideromelane shards at Site 483; and (3) an indurated, cross-bedded hyaloclastite in Hole 483B. The ash layers in (1) are composed of colorless, fresh rhyolitic glass shards with minor dacitic and rare basaltic shards. These are thought to be derived from explosive volcanoes on the Mexican mainland. Most of the shards in (2) are fresh, but some show marginal to complete alteration to palagonite. The composition of the glass is that of a MORB-type tholeiite, low in Fe and moderately high in Ti, and possibly erupted from off-axis seamounts. Basaltic glass shards occurring in silt about 45 meters above the basement at Site 484 A in the Tamayo Fracture Zone show a distinctly alkalic composition similar to that of the single basement basalt specimen drilled at this site. The hyaloclastite in (3) is made up chiefly of angular sideromelane shards altered to smectite and zeolites (mainly phillipsite) and minor admixtures of terrigenous silt. A very high K and Ba content indicates significant uptake of at least these elements from seawater. Nevertheless, the unusual chemical composition of the underlying massive basalt flow is believed to be reflected in that of the hyaloclastite. This is a powerful argument for interpreting the massive basalt as a surface flow rather than an intrusion. Glass alteration is different in the glassy margins of flows than in thicker glassy pillow rinds. Also, it appears to proceed faster in coarse- than fine-grained sediments.

Annotated record of the detailed examination of Mn deposits from the cruise of the SS Amra in the Maldives

In this volume, Agassiz gives a detailed account of the results of the cruise the steamer "Amra" chartered from the British India Steam Navigation Company. The cruise covered the attols of the Maldives archipelago. The deep sea formations are described in detail.

Annotated record of the detailed examination of Mn deposits from the R/V Galathea II Danish Deep Sea Expedition, 1950-1952

The Danish Expedition of the "Galathea II" around the world brought important results concerning the marine organisms in the deep sea. The "Galathea II" showed not only different organisms of the Abyssal but for the first time of the deepest trenches of the western Pacific. Anton Bruun coined the term Hadal for the region below the Abyssal under 6000 m. Although the "Galathea II" aimed to investigate new deep sea regions beside the routes of former expeditions and to widen the horizon of knowledge relating marine organisms the technical equipment and the methodological approach had partly been developed earlier. The expedition of the "Galathea II" is part of a long tradition of cruises such as that of the British "Challenger", the German "Valdivia" and the Swedish "Albatross" and especially the Danish cruises of the "Dana I" and "Dana II" which happened some years before.

(Table 1) Soil density and concentration of 10Beryllium and 26Aluminium in samples from two ash deposits in the McMurdo Dry Valleys

The McMurdo Dry Valleys, Antarctica (MDV) are among the oldest landscapes on Earth, and some landforms there present an intriguing apparent contradiction such that millions of years old surface deposits maintain their meter-scale morphology despite the fact that measured erosion rates are 0.1-4 m/Ma. We analyzed the concentration of cosmic ray-produced 10Be and 26Al in quartz sands from regolith directly above and below two well-documented ash deposits in the MDV, the Arena Valley ash (40Ar/39Ar age of 4.33 Ma) and the Hart ash (K-Ar age of 3.9 Ma). Measured concentrations of 10Be and 26Al are significantly less than expected given the age of the in situ air fall ashes and are best interpreted as reflecting the degradation rate of the overlying sediments. The erosion rate of the material above the Arena Valley ash that best explains the observed isotope profiles is 3.5 ± 0.41 x 10**-5 g/cm**2/yr (~0.19 m/Ma) for the past ~4 Ma. For the Hart ash, the erosion rate is 4.8 ± 0.21 x 10**-4 g/cm**2/yr (~2.6 m/Ma) for the past ~1 Ma. The concentration profiles do not show signs of mixing, creep, or deflation caused by sublimation of ground ice. These results indicate that the slow, steady lowering of the surface without vertical mixing may allow landforms to maintain their meter-scale morphology even though they are actively eroding.

Annotated record of the detailed examination of Mn deposits from DODO Expedition stations

The cores and dredges described in this report were taken on the DODO Expedition in May 1964 until December 1964 by the Scripps Institution of Oceanography from the R/V Argo. A total of 290 cores and dredges were recovered and are available at Scripps for sampling and study.