RV Farnella 4/81

Cruise summary report

Cruise Info. 
Ship name (ship code)RV Farnella (74AE)
Cruise identifier4/81
Cruise period1981-11-28 — 1981-12-19
Port of departurePonta Delgada, Portugal
Port of returnBelem, Brazil
Objectives1. To lay tide gauges at seven locations along the Mid-Atlantic Ridge between the Azores and South America.
2. To run GLORIA and other geophysical equipment between the tide-gauge deployments, with the following objectives:
(a) To determine the separation direction of the North American and African plates at several points along the Mid-Atlantic Ridge by mapping the precise locations and directions of several large-offset transform faults,
(b) To measure the ratio of inward to outward facing fault scarps near the Mid-Atlantic Ridge.
(c) To investigate the extension of Fifteen Twenty fracture zone and the possible North America/South America plate boundary west of the Mid-Atlantic Ridge.
(d) To study how fracture zone morphology is affected by spreading direction changes.
(e) To obtain some GLORIA runs over Vema fracture zone.
All the aims were successfully achieved with the exception of (d) and (e).
Chief scientistRoger C Searle (Institute of Oceanographic Sciences Wormley Laboratory)
Cruise reportRV Farnella 4/81 cruise report farnella4_81.pdf (0.45 MB) 
Ocean/sea areas 
GeneralNorth West Atlantic Ocean (limit 40W)
Caribbean Sea
Track chartsRV Farnella 4/81 cruise track — trk2897.html
Physical oceanography 
Sea level (inc. bot. press., inverted echosounder)Quantity: 7
Description: 7 deepsea tide gauges between 3066 and 4850 m
Geology and geophysics 
Multi-beam echosoundingQuantity: track kilometres = 6482
Long/short range side scan sonarQuantity: track kilometres = 5556
Single channel seismic reflectionQuantity: track kilometres = 1482
Gravity measurementsQuantity: track kilometres = 8334
Magnetic measurementsQuantity: track kilometres = 5926.4