Plattform Platform	Reise-Nr. Cruise-No.	Zeitraum Period	Projekt Project	Arbeitsgebiet Working area
Meteor	M193	08.09.2023 - 06.10.2023	REPLENISH	Red Sea

Fahrtleiter Chief Scientist	Institut Institute	Auslaufhafen Port of departure	Einlaufhafen Port of return	Stationskarte Station map	Schiffsroute Trackchart
Ludmann Thomas	UNI HAMBURG	Limassol	Jiddah

Ziel der Reise / Objectives of Cruise:

Although the Red Sea is situated within the Saharo-Arabian desert belt, a key-area for palaeoclimatic and palaeoanthropological research, its marine realm, including climate archives, is only locally and sporadically studied. Therefore, the cruise M193 aims to investigate whether and how Pleistocene humidity-aridity phases are recorded in marine sediments; how these periods affected the development of shallow- and deep-water carbonate systems along offshore western Saudi Arabia; and where unique warm-water (>20?C) high-salinity deep-sea corals assemblages with an unclear taxonomy thrive. Based on recent seafloor mapping and gravity coring, we are investigating the Al Wajh carbonate platform area that hosts a deep-sea fan fed by one of the largest onshore drainage systems on the Arabian Peninsula during Pleistocene pluvial phases, several isolated mini basins related to salt tectonics, and dozens of deep-sea coral habitats and drowned shallow-water reefs. While seismic measurements are planned to investigate the evolution of the Late Pliocene to Pleistocene marginal sediment system under sea-level and climatic change, gravity coring of isolated and communicating sediment basins will allow high-resolution studies of Upper Pleistocene humidity-aridity phases. Mapping and sampling of the largely unstudied deep-water coral habitats via ROV, and taxonomy studies will round up our survey. The cruise started at the 8th September from the port of Limassol (Cyprus). After the passage of the Suez Canal the study area was reached at the 12th September. It is located in front and north of the Al Wajh carbonate Platform and extended from the inner shelf to the center of the Red Sea Basin in the Saudi Arabian sector. It has an extend of 13,206 km² and was subdivided into three subareas (A, B and C). The research work commenced on the 12th September at 21:50 LT in area A, north of the Al Wajh platform. Here, we executed three ROV dives of which two had to be aborted because of technical problems with the ROV. The multi-channel seismic block in area A comprised 456 nm and started on the 15th September at 12:30 LT and ended on the 19th September at 01:30 LT. The profiling was several times interrupted because of compressor malfunction due to overheating of the control unit. At each ROV station, a CTD was run and box core as well as grab samples were taken along the ROV track. In addition, four gravity core stations where selected, three in mini-basins and one on a local high. The recovery was at each location about 12 m. The work in area B started on the 22nd September at 06:00 LT with multi-channel seismics. The acquisition lasted 4 days and finished on the 26th September at 10:00 LT. Afterwards, three ROV dives where successfully conducted at a submarine volcano in the Mabahiss Deep, a submarine canyon off the Al Wajh Platform and at the flank of a shallow plateau north of the platform. At each ROV location CTD, grab samples and box cores where obtained. In the Mabahiss Deep, an 18 m gravity core was deployed with about 12 m recovery. The research in area C started on the 30th September at 09:00 LT with a ROV dive in the south of the Al Wajh Platform at detached carbonate block. Another three dives followed, two at submerged carbonate blocks and one near a brine pool. All dives lasted 8-10 hours and were accompanied by grab and box core sampling as well as CTD casts. The streamer and air pulsers were deployed at 18:37 LT on the 30th of September and profiling were completed at the 1st October, at 10:00 LT. In area C, tow gravity cores were taken, one on top of a sediment covered salt uplift and the second in a brine pool. After that we steamed back to area B where we retrieved a gravity core in a small basin in front of a lowstand delta. In general, hydroacoustic date were collected during seismic profiling at night between the ROV dives, to fill the gaps between the seismic lines.

Messungen / Measurements