Poseidon Berichte - Paphsanias Volcano Cruise POS512, 25.04.2017 – 06.05.2017, Heraklion (Griechenland) – Heraklion (Griechenland)

Summary Cruise POS512 was scheduled for ten working days from 25.4. to 6.5.2017 in order to (1) produce a bathymetric map of the Epidavros Basin near the peninsula of Methana, (2) survey the volcanic structures of the Paphsanias Volcanic Field with the ROV PHOCA, and (3) sample the volcanic rocks. The Paphsanias Volcanic Field was found in 1987 but only one rock sample had been recovered and the size, age and composition of the lavas were unknown. Historic reports suggested an eruption on Methana and potentially off the coast some 2000 years ago. The bathymetric survey showed that six volcanic structures form the volcanic field ranging from simple lava flows on the seafloor, small cone-like structures to relatively complex crater-like structures with small volcanic domes. The largest volcanoes are about 200 m high and have diameters of about 2 km. The northern two complex Volcanoes 1 and 2 are relatively young and consist of steep lava flows and dome-like structures with little sediment. No indication of very young volcanism and hydrothermal activity was found. In contrast, the four southern structures are mostly sediment-covered and outcrops of volcanic rocks are rare and often covered by thick carbonate and MnOOH crusts. These four edifices are older than the northern two. Lava samples range from olivine-bearing basalts to plagioclase-amphibole-biotite-phyric andesites and dacites. All lavas appear to be fresh but few show signs of submarine extrusion and quenching. Volcaniclastic material was rarely observed and sampled indicating that explosive volcanic activity did not occur. During cruise POS512 13 ROV dives recovered 163 samples including 131 fresh lavas from four different volcanoes of the Paphsanias Volcanic Field and 427 nm of bathymetric survey was carried out

Detailed Mapping and Sampling of the Reykjanes Ridge, Cruise No. MSM75, 29 June 2018 - 8 August 2018, Reykjavik - Reykjavik, REYKJANES

Hotspot-influenced spreading axes are characterized by a shallow axis, thickened crust, and possibly by higher-than-normal eruption frequency, all signs of an excess of magma and heat being supplied to such ridges by the hotspot. Despite this, these ridges are also characterized by an apparently lower-than-average incidence of high-temperature hydrothermal venting, raising questions about their thermal budget. The type example for hotspot-ridge interaction is the Reykjanes Ridge south of Iceland, which shows abnormally shallow bathymetry between the Reykjanes Peninsula at ca. 63°N and the Charlie Gibbs Fracture Zone at 53°N.The seafloor surrounding the present spreading axis is also characterized by V-shaped bathymetric ridges, thoughtto be produced by regions of excess melting migrating along the axis through time. Cruise MSM75aimed to produce geological maps of four key areas along the ridge -one with thickened crust where a V-shaped ridge intersects the present-day axis, one with thickened crust but no on-axis V-shaped ridge anomaly, a third with more normal crustal thickness and an axial valley and a fourth at the only known, but up to present unsampled, Reykjanes hydrothermal site Steinaholl. This geological mapping is to be usedto investigate questions of variations in eruption size or frequency away from Iceland, the interplay between magmatism and tectonism, the axial volcanology of V-shaped ridges and how thick crust is cooled in the apparent paucity of high-temperature vent fields

Report and preliminary results of R/V SONNE Cruise SO251 - Extreme events Archived in the GEologial Record of JAPAN's subduction margins (EAGER-JAPAN)

Leg A SO251-1, Yokohama - Yokohama, 04.10.2016 - 15.10.2016, Leg B SO251-2, Yokohama - Yokohama, 18.10.2016 - 02.11.201

GEOMAR TV: Folge 1

Mit der Serie GEOMAR TV berichtet das GEOMAR über seine aktuellen Forschungsthemen Folge 1 widmet sich der SONNE-Ausfahrt zum Manihiki-Plateau im Westpazifik, dem Langzeit-Experiment zur Ozeanversauerung mit den KOSMOS Mesokosmen in Westschweden und Forschungsarbeiten zur Auswirkungen des Klimawandels auf Lebewesen am Boden der Ostsee mit den Kieler Benthokosmen. Außerdem wird JAGO vorgestellt - Deutschlands einziges bemanntes Forschungstauchboot. Weitere News: ROV HYBIS und der Bildband über den Sonderforschungsbereich zu Subduktionszonen "Am Puls der Erde

Black Smokers: Ore Factories of the Deep = Schwarze Raucher: Erzfabriken der Tiefsee

At the bottom of the sea, in a depth of several thousand metres, black smokers bring up valuable raw materials from inside the earth. Their metre-high vents seem to give off smoke like under water industrial chimneys. Am Meeresboden, in mehreren tausend Metern Wassertiefe befördern Schwarze Raucher wertvolle Rohstoffe aus dem Erdinneren herauf. Ihre meterhohen Schlote scheinen wie unterseeische Industrieschornsteine zu qualmen

Updated seafloor topography and T phase seismicity at Monowai, northern Kermadec Arc

Monowai is an active submarine volcanic centre in the Kermadec Arc, Southwest Pacific Ocean. Multi-beam data acquired during expedition SO225 aboard R/V SONNE in December 2012 indicates that the topography of the main stratocone has evolved significantly since the last survey in June 2011. Bathymetric measurements of the edifice reveal differences of up to 42 m in seafloor depth and indicate a net volume increase of ∼0.037 km3 across the summit area. Explosive volcanism observed onsite during the SO225 mapping campaign could be linked to a 20h-long swarm of unusually coherent T phase arrivals, suggesting that Monowai is a prime source of broadband seismic noise in the Southwest Pacific region during times of activity. Our findings further document the dynamic nature of volcanic processes at Monowai and have implications for future expedition planning

GEOMAR: Von der Tiefsee bis zur Atmosphäre = GEOMAR: From the Deep Sea to the Atmosphere

Das GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel ist eine der weltweit führenden Einrichtungen auf dem Gebiet der Meeresforschung. Wissenschaftler des GEOMAR untersuchen die chemischen, physikalischen, biologischen und geologischen Prozesse im Ozean und ihre Wechselwirkung mit dem Meeresboden und der Atmosphäre. GEOMAR Helmholtz Centre for Ocean Research Kiel is one of the world’s leading institutes in the field of marine sciences. GEOMAR scientists investigate the chemical, physical, biological and geological processes of the seafloor, oceans and ocean margins and their interactions with the atmosphere