Unknown
PANGAEA
In:
Supplement to: Jones, E J W; Laughton, Anthony S; Hill, M N; Davies, D (1976): A geophysical study of part of the western boundary of the Madeira-Cape Verde Abyssal plain. Deep Sea Research and Oceanographic Abstracts, 13(5), 889-907, https://doi.org/10.1016/0011-7471(76)90909-8
Publication Date:
2023-08-28
Description:
The results are discussed of a geophysical survey undertaken by R.R.S. Discovery II early in 1962 in an area centred on 29° 15'N, 25° 5'W at the western extremity of the Madeira-Cape Verde Abyssal Plain. Seismic investigations show that the sediments are underlain by an intermediate layer about 2 km in thickness of velocity 4.1-5.4 km/sec which overlies a deep layer 5.2-km thick of velocity 6.3-6.8 km/sec. Refracted arrivals on the longest seismic line give a depth of 13.2 km to the M discontinuity.
Magnetic results indicate that the topography of the abyssal hills in the western part of the area is probably continued eastwards as sub-bottom relief beneath the sediments of the abyssal plain. They also support the hypothesis that the intermediate seismic layer (layer 2) is composed predominantly of volcanic rocks. Examination of a well-defined magnetic anomaly over one topographic feature ("The Madcap Volcano") shows it to be composed of magnetized rocks (I = 8.4 × 10**-3 e.m.u./cm**3) having a direction of magnetization which points upwards at 25° with an azimuth of 305°. Measurements at ten heat flow stations show that the average geothermal flux in this region is 1.20 (±0.11) µcal/cm**2/sec.
Keywords:
Atlantic Ocean; D4810; D4814; Deposit type; DEPTH, sediment/rock; Description; Discovery II (1929); Event label; File name; Identification; MADCAP_62; NOAA and MMS Marine Minerals Geochemical Database; NOAA-MMS; Photo/Video; Position; PV; Quantity of deposit; Sediment type; Substrate type; Uniform resource locator/link to image; Visual description
Type:
Dataset
Format:
text/tab-separated-values, 26 data points
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