High-resolution sediment record from a submarine meandering canyon system in the eastern Atlantic

Based on a high-resolution sediment record from a submarine meandering canyon system offshore the present-day hyperarid Saharan Africa, two phases of turbidity-current activity can be distinguished during the past 13,000 years. Frequent, siliciclastic turbidity currents can be related to deglacial sea-level history, whereas rhythmically recurring fine-grained and carbonate-rich turbidity currents with recurrence times of roughly 900 years are inferred for the Holocene. Various trigger mechanisms can be considered to initiate turbidity currents, but only a few can explain a periodic turbidite activity. A comparison of Holocene turbidite recurrence times and basic cycles of 900 and 1,800 years found in various Holocene paleoclimate studies suggests that a previously unrecognized climate-related coupling may be active.

Chemistry of the massive sulfide deposit at DSDP Hole 63-471

We report here chemical analyses of sulfide and other minerals occurring in the massive sulfide deposit cored at Site 471. Details of the mineralogy and inferred paragenesis of the deposit will be reported elsewhere. The sulfide deposit at Site 471 occurs between overlying pelagic sediment and underlying basalt. The deposit is vertically zoned and consists, from top to bottom, of the following mineral assemblages: (1) pyrite, chalcopyrite, and Zn-sulfide in chert and calcite gangue (about 35 cm thick); (2) a 5-cm-thick metalliferous sediment layer described in detail by Leinen (this volume); and (3) a 4-cm-thick chert layer. The overlying sediment is a calcareous silty claystone that contains middle Miocene coccoliths (Bukry, this volume). The underlying basalt has been extensively chloritized and veined with calcite. In places feldspars are albitized, and calcite occurs as pseudomorphs after olivine. Relict textures suggest that the basalt grades into diabase and gabbro with increasing depth. Neither stock work nor disseminated sulfides was observed in the altered rocks.

Abundance of large protists from the Infrakingdom Rhizaria in the global ocean

The present data set is a worldwide compilation from 11 oceanographic expeditions during which an underwater vision profiler (UVP) was deployed in situ to determine the vertical distribution (abundance) of 10 taxonomic/morphological groups of plankton larger than 600 µm, belonging to the Infrakingdom Rhizaria, including Phaeodaria, Radiolaria, Collodaria and Acantharia.

Environmental context of a compilation about the distribution of large protists from the Infrakingdom Rhizaria in the global ocean

The present data set provides environmental context to a worldwide compilation from 11 oceanographic expeditions during which an underwater vision profiler (UVP) was deployed in situ to determine the vertical distribution plankton larger than 600 µm, belonging to the Infrakingdom Rhizaria.