Secondary mineral assemblages in a volcanic sequence of ODP Hole 104-642E

Mineralogical and geochemical analyses of alteration products from upper and lower volcanic series recovered during ODP Leg 104 reveal variations both in composition and order of crystallization of clay minerals vesicles and voids filling and replacing glass. These results provide information about successive alteration stages of rocks and interlayered volcaniclastic sediments. The first stage, related to initial basalt-seawater interaction, is characterized by development of Fe-smectites, especially Fe-rich saponite. A second stage of intermittently superimposed subaerial weathering is marked by iron-oxides-halloysite-kaolinite formation. The third episode, interpreted as hydrothermal on the basis of O-isotopic data, is defined by postburial coprecipitation of Fe-poor, Mg-rich saponite and celadonite. A distinct final and pervasive hydrothermal stage, occurring mainly in the lower series and dominated by Al-smectites-zeolites assemblage, indicates changes toward a more reducing alteration environment.

Tab. 1: Meerfelder Maar Drilling B4, stratigraphy and sequence of the lake sediments (pdf 215 kB)

A core from Meerfelder Maar, with a basal age of 29,000 years, provides a continuous sedimentary sequence from Late-Glacial times to the present. It includes the stratigraphical marker of the Laach Pumice Tuff. Sedimentological, geochemical, palynological, palaeobiological, palaeomagnetic and palaeontological analyses permit reconstructions of the history of the lake and its catchment area, and hence of the climate of the region, to be made. The discovery of Middle Oligocene marine, detrital fossils in the maar sediments provides insights into the palaeogeography of the Eifel region during Tertiary times.

(Table 1) Permanent currents in the Campeche Bank area based on data of 24-hour stations

Data of twenty buoy stations were used to compile a new chart of permanent currents in the surface layer (10 m depth) for the region of the Yucatan shelf (Campeche Bank). It was found that vertical variations in direction of the currents are insignificant within the shallow plateau of the banks.

Table 6 Generalised properties of Utsira caprocks, based on analysis of cuttings (page 79)

Executive Summary: Carbon dioxide capture and storage (CCS) is one option for mitigating atmospheric emissions of carbon dioxide and thereby contributes in actions for stabilization of atmospheric greenhouse gas concentrations. The Bellona Foundation is striving to achieve wide implementation of carbon dioxide (CO2) capture and storage both in Norway and internationally. Bellona considers CCS as the only viable large scale option to close the gap between energy production and demand in an environmentally sound way, thereby ensuring that climate changes and acidification of the oceans due to increased CO2 concentrations in the atmosphere will be stabilised. ff