Analysis of Manganese nodules from Sonne cruises SO06/1 and /2, "Hawaii-Tahiti-Transect", Teilprojekt ICIME

Manganese nodules research has focused on the area between the Clarion Fracture Zone to the North and the Clipperton Fracture Zone to the South where significant concentrations were found ni Ni-Cu. During the CCOP/SOPAC-IOC/IDOE International workshop on the "Geology Mineral Resources and Geophysics of the South Pacific" held in Fiji in September 1975, a working group on manganese nodules was formed by scientists from: CNEXO, Brest, the Institute of Oceanography, New Zealand, Imperial College, London and the Technical University of Aachen. A draft project was presented in July 1976 by J. Andrews, University of Hawaii and G. Pautot, Cnexo on a joint survey under the name of: "Hawaii-Tahiti Transect program". Further details were worked on in September 1976 during the International Geological Congress in Sydney with the participation of D. Cronan, Imperial College, Glasby, New Zealand Geological Survey and G. Friedrich, Aachen TU. The scientific final program was established in July 1977, planning on the participation of three research vessels: the Suroit (CNEXO), the Kana Keoki (U. of Hawaii) and the Sonne (Aachen TU). Several survey areas were selected across the Pacific Ocean (Areas A, B, C, D, E, F, G and H) with about the same crustal age (about 40 million years) and a similar water depths. Being near large fault zones, the ares would be adequate to study the influences of biological productivity, sedimentation rate and possibly volcanic activity on the formation and growth of manganese nodules. The influnece of volcanic activity study would particularly apply to area G being situated near the Marquesas Fracture Zone. The cruise from R/V Sonne started in August 1978 over areas C, D, F, G K. The R/V suroit conducted a similar expedition in 1979 over areas A, B, C, D, E, H and I. Others cruises were planned during the 1979-1980 for the R/V Kana Keoki. The present text relates the R/V Sonne Cruises SO-06/1 and SO-06/2 held within the frame work of this international cooperative project.

Slow-sinking particle export measured in the North Atlantic during the M87/1 cruise in April 2012

Slow-sinking particles were sampled using the Marine Snow Catcher (MSC). For a full description of the MSC and flux calculations see Riley et al. (2012). The MSC was deployed at four depths between 50 - 650 m during four visit at Stations 1 (63°3' N 11°0' W) and three visits at Station 2 (62°5' N 2°3' W) to obtain depth profiles of slow-sinking material. The MSC was further deployed at 50 m during two visits at Station 3 (60°2' N 1°0' E). A total of 33 MSC were deployed. Slow-sinking particles were analysed for particulate organic carbon (POC), particulate inorganic carbon (PIC), biogenic silica (BSi), and Chlorophyll a (total, >10 µm).

Raw grain-size distributions of the sediment trap time series CB 14 upper, CB 15 lower, CB 16 lower, CBi 1 upper, CBi 2 upper and CBi 3 upper

in preparation

(Supplementary Table 1) Proportions of methane (C1) to ethane (C2) and the stable isotope composition of methane (d13CCH4) of gas and oil collected by gas bubble sampler during cruise M 114 in the southern Gulf of Mexico

Hydrocarbon seepage is a widespread process at the continental margins of the Gulf of Mexico. We used a multidisciplinary approach, including multibeam mapping and visual seafloor observations with different underwater vehicles to study the extent and character of complex hydrocarbon seepage in the Bay of Campeche, southern Gulf of Mexico. Our observations showed that seafloor asphalt deposits previously only known from the Chapopote Knoll also occur at numerous other knolls and ridges in water depths from 1230 to 3150 m. In particular the deeper sites (Chapopopte and Mictlan knolls) were characterized by asphalt deposits accompanied by extrusion of liquid oil in form of whips or sheets, and in some places (Tsanyao Yang, Mictlan, and Chapopote knolls) by gas emission and the presence of gas hydrates in addition. Molecular and stable carbon isotopic compositions of gaseous hydrocarbons suggest their primarily thermogenic origin. Relatively fresh asphalt structures were settled by chemosynthetic communities including bacterial mats and vestimentiferan tube worms, whereas older flows appeared largely inert and devoid of corals and anemones at the deep sites. The gas hydrates at Tsanyao Yang and Mictlan Knolls were covered by a 5-to-10 cm-thick reaction zone composed of authigenic carbonates, detritus, and microbial mats, and were densely colonized by 1-2 m-long tube worms, bivalves, snails, and shrimps. This study increased knowledge on the occurrences and dimensions of asphalt fields and associated gas hydrates at the Campeche Knolls. The extent of all discovered seepage structure areas indicates that emission of complex hydrocarbons is a widespread, thus important feature of the southern Gulf of Mexico.

(Table 1) Isotopic and geochemical parameters of gas phase from underground fluids of the Baikal rift and its framing

Results of studying isotopic composition of helium in underground fluids of the Baikal-Mongolian region during the last quarter of XX century are summarized. Determinations of 3He/4He ratio in 139 samples of gas phase from fluids, collected at 104 points of the Baikal rift zone and adjacent structures are given. 3He/4He values lie within the range from 1x10**-8 (typical for crustal radiogenic helium) to 1.1x10**-5 (close to typical MORB reservoir). Repeated sampling in some points during more than 20 years showed stability of helium isotopic composition in time in each of them at any level of 3He/4He values. There is no systematic differences of 3He/4He in samples from surface water sources and deeper intervals of boreholes in the same areas. Universal relationship between isotopic composition of helium and general composition of gas phase is absent either, but the minimum 3He/4He values occurred in methane gas of hydrocarbon deposits, whereas in nitrogen and carbon dioxide gases of helium composition varied (in the latter maximum 3He/4He values have been measured). According to N2/Ar_atm ratio nitrogen gases are atmospheric. In carbonic gas fN2/fNe ratio indicates presence of excessive (non-atmogenic) nitrogen, but the attitude CO2/3He differs from one in MORB. Comparison of helium isotopic composition with its concentration and composition of the main components of gas phase from fluids shows that it is formed under influence of fractionation of components with different solubility in the gas-water system and generation/consumption of reactive gases in the crust. Structural and tectonic elements of the region differ from the spectrum of 3He/4He values. At the pre-Riphean Siberian Platform the mean 3He/4He = (3.6+/-0.9)x10**- 8 is very close to radiogenic one. In the Paleozoic crust of Khangay 3He/4He = (16.3+/-4.6)x10**-8, and the most probable estimate is (12.3+/-2.9)x10**-8. In structures of the eastern flank of the Baikal rift zone (Khentei, Dauria) affected by the Mz-Kz activization 3He/4He values range from 4.4x10**-8 to 2.14x10**-6 (average 0.94x10**-6). Distribution of 3He/4He values across the strike of the Baikal rift zone indicates advective heat transfer from the mantle not only in the rift zone, but also much further to the east. In fluids of the Baikal rift zone range of 3He/4He values is the widest: from 4x10**-8 to 1.1x10**-5. Their variations along the strike of the rift zone are clearly patterned, namely, decrease of 3He/4He values in both directions from the Tunka depression. Accompanied by decrease in density of conductive heat flow and in size of rift basins, this trend indicates decrease in intensity of advective heat transfer from the mantle to peripheral segments of the rift zone. Comparing this trend with data on other continental rift zones and mid-ocean ridges leads to the conclusion about fundamental differences in mechanisms of interaction between the crust and the mantle in these environments.