RRS Discovery D178
Cruise summary report
|Ship name (ship code)||RRS Discovery (74E3)|
|Cruise period||1988-11-08 — 1988-12-07|
|Port of departure||Viana do Castelo, Portugal|
|Port of return||Gibraltar, Gibraltar|
|Objectives||To investigate the nature and crustal structure of the Madeira-Tores Rise in the vicinity of Josephine Seamount using:
1. A 250km long wide-angle seismic line recorded on six Cambridge digital ocean-bottom seismometers (DOBS), using closely spaced explosve charges and airgun shots.
2. A grid of underway single channel reflection, gravity, magnetic and bathymetry profiles in order to give regional control.
3. A test of the DOBS triggered mode, to monitor micro-earthquake activity on the sea bed.
4. Heat flow profiles.
Work was confined to a small area of international water between Portugal, Madeira and the Azores. Investigations concentrated on the Madeira-Tores Rise, the Horseshoe Abyssal Plain and the Ampere Seamount. Work was confined to a box delineated by 38N 15W, 39N 14W, 35N 12W, 34N 12W, 34N 12.5W, 37N 16W and to international waters within this box. The main DOBS/shot firing line ran between 35 37N 13 17W and 38 11N 14 53W.
|Chief scientist||Penny J Barton (University of Cambridge Department of Earth Sciences)|
|Cruise report||(1.43 MB)|
|General||North East Atlantic Ocean (limit 40W)|
|Specific||Madeira - Tore Rise|
|Bathythermograph||Quantity: number of profiles = 6|
|Other physical oceanographic measurements||Quantity: number of profiles = 1|
Description: sound velocity
|Geology and geophysics|
|Single-beam echosounding||Quantity: track kilometres = 2850|
|Multichannel seismic reflection||Quantity: track kilometres = 1440|
|Seismic refraction||Quantity: track kilometres = 270|
|Gravity measurements||Quantity: track kilometres = 2850|
|Magnetic measurements||Quantity: track kilometres = 1850|
|Other geological/geophysical measurements||Quantity: number of measurements = 24|