caa a22 4500 386401675 CHVBK 20180307112201.0 cr unu---uuuuu 161130e198911 xx s 000 0 eng 10.1017/S0016756800006944 doi S0016756800006944 pii (NATIONALLICENCE)cambridge-10.1017/S0016756800006944 The Adola Fold and Thrust Belt, southern Ethiopia: a re-examination with implications for Pan-African evolution [Elektronische Daten] The Adola Fold and Thrust Belt of Ethiopia is a late- Precambrian, north-south trending belt of volcanic-sedimentary and ophiolite-like units overlying ‘basement rocks' (gneisses and granitic gneisses). Detailed structural analysis and data from microfabrics have documented two thrusting events (D1, D5) and three folding phases (F2, F3, F4). All deformations have affected both the rocks of the Adola Fold and Thrust Belt and the ‘older basement'. The structural history is recorded as follows: (1) formation of ductile shear zones (Dl); (2) progressive development of recumbent folds (F2); (3) a superimposed north-south trending, tight to isoclinal, upright penetrative folding phase (F3), which imparted the dominant structure of the region; (4) F3 was later gently affected, at right angles to F3, by the last folding event (F4). Metamorphic conditions during this deformational cycle reached highest greenschist to medium amphibolite facies conditions. Close to major thrust contacts imbrication produced metamorphic discontinuities. Marked retrograde metamorphism in narrow horizons indicates a continuation of minor movements along the major thrusts, postdating the metamorphic peak. Evidence of a second thrusting/faulting episode (D5) is only recorded at the mesoscale. This latter event was accompanied by very low to low grade metamorphic conditions. In accepting the previously reported age of 1030±40 Ma for the volcanic-sedimentary unit of the Adola Fold and Thrust Belt, and the interpretation of these units as an immature island arc, a possibly early Pan-African oceanic accretion is postulated. Copyright © Cambridge University Press 1989 "Beraki W. H. Ethiopian Institute of Geological Surveys Training Project, UNDP ETH 86/034, P.O.BOX 5580, Addis Ababa, Ethiopia Bonavia F. F. Cooperazione Italiana Universitaria, c/o Department of Geology, Addis Ababa University, Addis Ababa, Ethiopia Getachew T. Ethiopian Institute of Geological Surveys Training Project, UNDP ETH 86/034, P.O.BOX 5580, Addis Ababa, Ethiopia Schmerold R. Ethiopian Institute of Geological Surveys Training Project, UNDP ETH 86/034, P.O.BOX 5580, Addis Ababa, Ethiopia Tarekegn T. Ethiopian Institute of Geological Surveys Training Project, UNDP ETH 86/034, P.O.BOX 5580, Addis Ababa, Ethiopia Geological Magazine Cambridge University Press 126/6(1989-11), 647-657 0016-7568 126:6<647 1989 126 GEO https://doi.org/10.1017/S0016756800006944 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1017/S0016756800006944 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- "Beraki W. H. Ethiopian Institute of Geological Surveys Training Project, UNDP ETH 86/034, P.O.BOX 5580, Addis Ababa, Ethiopia NATIONALLICENCE 700 1- Bonavia F. F. Cooperazione Italiana Universitaria, c/o Department of Geology, Addis Ababa University, Addis Ababa, Ethiopia NATIONALLICENCE 700 1- Getachew T. Ethiopian Institute of Geological Surveys Training Project, UNDP ETH 86/034, P.O.BOX 5580, Addis Ababa, Ethiopia NATIONALLICENCE 700 1- Schmerold R. Ethiopian Institute of Geological Surveys Training Project, UNDP ETH 86/034, P.O.BOX 5580, Addis Ababa, Ethiopia NATIONALLICENCE 700 1- Tarekegn T. Ethiopian Institute of Geological Surveys Training Project, UNDP ETH 86/034, P.O.BOX 5580, Addis Ababa, Ethiopia NATIONALLICENCE 773 0- Geological Magazine Cambridge University Press 126/6(1989-11), 647-657 0016-7568 126:6<647 1989 126 GEO CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge