TECHNO encrustation description and analysis

The distribution of radioactivities in a large polymetallic encrustation (TECHNO) sampled from the Pacific sea floor has been studied in great detail. The study includes measurements of the long-lived U and Th decay series isotopes, alpha-particle tracks and SUP-10 Be and SUP-26 Al (Results on the latter two cosmonuclides have been reported by Guichard, Reyss and Yokoyama, 1978). The data are discussed in terms of their implication on age dating of the sample. Two interpretations of the data are presented leading to vastly different time scales for the formation of the sample. Here the opinion is divided among the authorship. One group, as well as Guichard et al (1978), favours the million-years scale and the other favors scale measured in thousands of years. The principal pros-and-cons aspects of the two views are mentioned.

European lobsters (Homarus gammarus) captured around the rocky island of Helgoland (German Bight, North Sea) from 2005 to 2015 - A mark-recapture program -

European lobsters were captured by employees of the Marine Biological Station and local fishermen from the rocky subtidal zone around the island of Helgoland (North Sea, 54°11.3'N, 7°54.0'E) and from the Helgoland Deep Trench, located south west of the island. The animals were captured by pots, traps, trawl and divers. All measured lobsters were tagged and released. A tagged lobster was classified by the absence or presence of colour tag and/or T-bar tag. Data of lobsters contains capture date, fresh weight, carapace lengths, sex and the information if lobsters were egg-bearing and tagged. Furthermore, data of commercial landed lobsters are included.

Average compositions and analyses range for clinopyroxene, olivines, orthopyroxene, and spinel from the MARK area at DSDP Site 45-395A, and ODP Site 153-920

Mineral compositions of residual peridotites collected at various locations in the Mid-Atlantic Ridge south of the Kane transform (MARK area) are consistent with generally smaller degrees of melting in the mantle near the large offset Kane transform than near the other, small offset, axial discontinuities in the area. We propose that this transform fault effect is due to along-axis variations in the final depth of melting in the subaxial mantle, reflecting the colder thermal regime of the ridge near the Kane transform. Calculations made with a passive mantle flow regime suggest that these along-axis variations in the final depth of melting would not produce the full range of crustal thickness variations observed in the MARK area seismic record. It is therefore likely that the transform fault effect in the MARK area is combined with other mechanisms capable of producing crustal thickness variations, such as along-axis melt migration, the trapping of part of the magma in a cold mantle root beneath the ridge, or active mantle upwelling.