During METEOR-Westafrica cruise 46, leg 1, geophysical measurements were carried out off Morocco between 31°30'N and 32°30'N in the time period from the 8th October to the 5th November 1977. Altogether 1,855 km of 24-fold reflection seismic data were collected on lines ME46-02 to ME46-11 and on lines ME46-14 to ME46-19. For the purpose of planning the programme, the reflection seismic data were processed (12-fold stack) aboard. 3,465 km of magnetic, gravimetric and bathymetric data were collected on lines ME46-01 to ME46-26 using the new BGR digital recording system. Along lines ME46-101 and ME46-102 with a total length of 209 km refraction seismic measurements were carried out with 6 moored telemetric buoys. A total of 164 shots with charges of 5 kg up to 200 kg were fired along the two lines in distances of about 1.5 km. A distinct fault zone was discovered in the area of investigation which is associated with a positive magnetic anomaly. The fault zone strikes NNE-SSW and probably marks the ocean-continent boundary. Beside diapiric structures (salt) allochthonous structures - thrust structures - are widespread features east of the discovered fault zone and below the lower continental slope. The seismic data indicate that the evolution of the old continental margin of the East Atlantic was also controlled by large scale gravity tectonics.
In the period from February 13th to March 2nd 1980 4,037 km of magnetic, gravity and bathymetric lines and 1,195 km of digital reflection seismic lines were recovered on the 2nd leg of METEOR cruise no. 53. Heat flow measurements have been performed on 13 stations; on two stations sonobuoy refraction measurements and dredging have been carried out. From a preliminary interpretation of the seismic monitor records the Mazagan Plateau is part of the Moroccan Meseta. Seawards of this stable swell lies the 75 km wide, downfaulted rift graben characterized by salt diapirs. A submarine body, 150 square kilometres large, lying at the foot of the Mazagan Escarpment in water depths of 3000 m - 3800 m beneath sea level, from which western flank few granitic fragments were retrieved, is interpreted as a subsided and tilted block of the Mazagan Plateau. The north-trending magnetic anomalies, discovered during METEOR cruise no. 46 within the Essaouira continental margin segment have also been recognized within the Tafelney Plateau segment, situated between latitudes 30°45'N and 31°30'N off Morocco. Two neo-volcanic zones were found west of the Conception Bank and west of the Betancuria Massif/Fuerteventura Is. The Mesozoic and Tertiary depositional sequences are highly deformed by small piercement structures interpreted as dykes within these zones.
The area of the 1st leg of METEOR cruise no. 67 lies off the Moroccan coast between longitudes 32.5°N and 35°N and latitude 12°W. Within this continental margin segment multichannel reflection seismic measurements were carried out in parallel with magnetic and gravimetric measurements on 22 lines with a total length of 4,378 km during the period from January 20th to February 13th 1984, with the research objectives: i) to collect new geophysical data for a better understanding of magmatic-volcanic and tectonic processes during the initial drifting phase, and ii) to search for suitable positions for deep drilling sites of the "Ocean Drilling Programme" in the transition zone between continental and oceanic crust. A distinct and sharp reflection seismic boundary running from about 31°30'N/11°W in the south to 34°30'N/10°25'W in the north separates flat-lying Mesozoic sediments overlying slightly structured basement of the Jurassic "Magnetic Quiet Zone" from the complex Moroccan piercement zone in the east. A prominent magnetic anomaly, called S1, is nearly coincident with the sharp reflection seismic boundary, and is thought to represent most probably the initial drifting zone. The Moroccan piercement zone is interpreted to represent the eastern part of a pre-Jurassic rift-basin which conjugated western part lies off Nova Scotia/Canada. Subsidence associated with small-scale rotational block-faulting was time-transgressive in the Moroccan piercement zone, e.g. it started in Triassic time in the central part of the rift-basin and affected successively its landward parts apparently due to successively cooling of the stretched and thinned crust. Weak magnetic anomalies trending approximately NE-SW were recorded within the Jurassic "Magnetic Quiet Zone" lying west of magnetic anomaly S1. These anomalies can be correlated over distances of up to 300 km. They are interpreted to represent either variations of the geomagnetic field intensity or field reversals during a time of weak geomagnetic field.
The METEOR cruise M20/3 from 4th February to 13th March 1992 had two scientific objectives: One research topic was to study the variability of the Mesozoic oceanic crust along two flow-line profiles located north of the Kane and Hayes Fracture Zones. The other research topic was the investigation of the weak magnetic anomalies in the Jurassic magnetic quiet zone north of the Canary Islands. Seismic data with a coverage of 2,400 % were acquired together with magnetic, gravimetric and hydroacoustic data along the two flow-line profiles with a total length of 1,595 km. Magnetic, gravimetric and hydroacoustic measurements were carried out on 31 profiles with a total length of 6,069 km in the Jurassic quiet zone north of the Canary Islands. On 10 of these lines multichannel seismic reflection data (2,138 km) have been acquired.
In the period from September 25th to October 19th 1979 5,260 km of magnetic, gravity and bathymetric lines and 3,567 km of reflection seismic lines were recovered on the first leg of the VALDIVIA Westafrica-cruise 1979 with the research objective to study similarities and differences in the geological development of physiographically different Northwest African continental margin segments. Test measurements have been carried out during this cruise with an “implosive" seismic sound source. The software for acquisition, calculation and presentation of gravity, magnetic and bathymetric data has been developed so that onboard presentation of free-air anomalies, Bouguer anomalies, anomalies of the earth's magnetic field and of the bathymetry could be achieved. Differences within the regional geological development of the Northwest African continental margin has been confirmed. Parts of the Moroccan continental margin are modified by a Cretaceous epirogenic uplift associated with block—faulting and halokinesis. Tertiary folding of the Western High Atlas extends into the shelf of the Tafelney Plateau segment.