The Morais ophiolite complex, also known as Morais Massif (''in Portuguese, Maciço de Morais''), is located in the northeast of

Portugal Portugal, officially the Portuguese Republic, In recognized minority languages of Portugal: :* mwl, República Pertuesa is a country located on the Iberian Peninsula, in Southwestern Europe, and whose territory also includes the Macaronesian ...

in the

Bragança District Bragança District ( pt, Distrito de Bragança ; mwl, Çtrito de Bergáncia) is a traditional political division of Portugal, in the northeast corner bordering on Spain ( Castile and Leon and Galicia), covering 7.4% of the nation's continental l ...

, with its main core in the

Macedo de Cavaleiros Macedo de Cavaleiros () is a city and municipality in northeastern Portugal, in Bragança District. The population in 2011 was 15,776, in an area of 699.14 km². History During antiquity, the region was occupied by the Celts, then Romans a ...

Municipality. Generally speaking the Morais ophiolite complex is a set of

allochthon upright=1.6, Schematic overview of a thrust system. The hanging wall block is (when it has reasonable proportions) called a window. A klippe is a solitary outcrop of the nappe in the middle of autochthonous material. An allochthon, or an alloc ...

ous units, which include a full range of

ultramafic rock Ultramafic rocks (also referred to as ultrabasic rocks, although the terms are not wholly equivalent) are igneous and meta-igneous rocks with a very low silica content (less than 45%), generally >18% MgO, high FeO, low potassium, and are compose ...

Geological uniqueness

Its uniqueness lies in the fact that, within a radius of about 50 km, it's possible to see the geologic evidences of the continental collision between

Laurussia Laurasia () was the more northern of two large landmasses that formed part of the Pangaea supercontinent from around (Mya), the other being Gondwana. It separated from Gondwana (beginning in the late Triassic period) during the breakup of Pang ...

and

Gondwana Gondwana () was a large landmass, often referred to as a supercontinent, that formed during the late Neoproterozoic (about 550 million years ago) and began to break up during the Jurassic period (about 180 million years ago). The final st ...

with the consequent closure of the

Rheic Ocean The Rheic Ocean was an ocean which separated two major palaeocontinents, Gondwana and Laurussia (Laurentia- Baltica-Avalonia). One of the principal oceans of the Palaeozoic, its sutures today stretch from Mexico to Turkey and its closure result ...

, to form the supercontinent of

Pangaea Pangaea or Pangea () was a supercontinent that existed during the late Paleozoic and early Mesozoic eras. It assembled from the earlier continental units of Gondwana, Euramerica and Siberia during the Carboniferous approximately 335 millio ...

in the Late

Paleozoic The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon. The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838 by combining the Greek words ''palaiós'' (, "old") and ' ...

(

Variscan orogeny The Variscan or Hercynian orogeny was a geologic mountain-building event caused by Late Paleozoic continental collision between Euramerica (Laurussia) and Gondwana to form the supercontinent of Pangaea. Nomenclature The name ''Variscan'', comes ...

). This

Geologic Complex In geology, a complex is a lithodemic unit consisting of two or more lithodemes of more than one genetic class ( metamorphic, igneous or sedimentary). The law of superposition is inapplicable to intrusive, highly deformed, or metamorphic bodies of ...

presents three main units: * the terrains once belonging to the stress edge of the

continent * the

ophiolite An ophiolite is a section of Earth's oceanic crust and the underlying upper mantle that has been uplifted and exposed above sea level and often emplaced onto continental crustal rocks. The Greek word ὄφις, ''ophis'' (''snake'') is found ...

: a complete sequence of

oceanic crust Oceanic crust is the uppermost layer of the oceanic portion of the tectonic plates. It is composed of the upper oceanic crust, with pillow lavas and a dike complex, and the lower oceanic crust, composed of troctolite, gabbro and ultramafi ...

(

obduction Obduction is a geological process whereby denser oceanic crust (and even upper mantle) is scraped off a descending ocean plate at a convergent plate boundary and thrust on top of an adjacent plate. When oceanic and continental plates converge, ...

of the

) * the terrains once belonging to the

continent

Notes

Sources

*Pereira, E., Ribeiro, A., Castro, P.F., 2000 – Carta Geológica de Portugal à escala 1:50.000. Notícia explicativa da Folha 7 - D (Macedo de Cavaleiros). Serv. Geol. de Portugal. *Pereira, E., Ribeiro, A., Castro, P. & De Oliveira, D., 2004 – Complexo Ofiolítico Varisco do Maciço de Morais (NE de Trás-os-Montes, Portugal). In Pereira, E., Castroviejo, R. & *Ortiz, F. (Eds.), “Complejos Ofiolíticos en Iberoamérica – Guías de Exploración para Metales Preciosos”, pp. 265–284. Proyecto XIII.1 – CYTED, Madrid, España. *Pereira, Z., Meireles, C. e Pereira, E., 1999 – Upper Devonian Palynomorphs of NE Sector of Trás-os-Montes (Central Iberian Zone). XV Reun. Geol. Oeste Peninsular, Resumos, pp. 201–206 *Pin, C., Paqette, J.L., Ibarguchi, J.G., Zalduegui, J.F., Aller, J.R. and Cuesta, L.A., 2000 - Geochronological and geochemical constraints on the origin of the ophiolitic units from the Northwestern Iberian Massif. GALICIA 2000, Variscan-Appalachian dynamics: the building of the Upper Paleozoic basement, Abstracts, pp. 146–147. *Rebelo, J.A. e Romano, M., 1986 - A contribution to the lithostragraphy and paleontology of the lower Paleozoic rocks of the Moncorvo region, Northeast of Portugal. Com. Serv. Geol. Portugal, T. 72, fasc.1/2, pp. 45–57. *Ribeiro, A., 1974 - Contribution à l'étude tectonique de Trás-os-Montes Oriental. Serv. Geol. de Portugal, Mem. 24, 168 p. *Ribeiro, A., Marcos, A., Pereira, E., Llana-Fúnez, S., Farias, P., Fernández, F.J., Fonseca, P., Chaminé, H.I. and Rosas, F., 2003 - 3-D strain distribution in the Ibero-Armorican Arc: a review. VI Cong. Nac. Geologia, Lisboa, Actas: D63-D64; Ciências da Terra (UNL), nº esp V, CD-Rom, D63-D64. *Ribeiro, A., Pereira, E. and Dias, R., 1990 - Structure in the NW of the Iberia Peninsula (Alloctonous sequences). In: Dallmeyer, R.D. and Martinez Garcia, E. (Eds.): Pre- Mesozoic Geology of Iberia, Springer-Verlag, p. 220-236. *Ribeiro, A., Silva, J.B., Dias, R., Pereira, E., Oliveira, J.T., Rebelo, J.A., Romão, J. e Silva, A.F., 1991 – Sardic inversion tectonics in the Centro-Iberian Zone. III Congr. Nac. Geol., Resumos, Coimbra, p. 71. *Ribeiro, M. L, 1986 - Geologia e Petrologia da região a Sw de macedo de Cavaleiros (Trás-os-Montes). Tese, Fac.Cienc. Univ. Lisboa, 202 p. *Rodrigues, J., Pereira, E. e Ribeiro, A., 2006 – Estrutura interna do Complexo de Mantos Parautóctones, sector de Murça-Mirandela (NE de Portugal). In: Dias, R & Araújo, A.(Eds.) Geologia de Portugal no Contexto da Ibéria. Universidade de Évora, pp. 63–84. *Sá, A.A., 2006 – A sucessão do Ordovícico superior de Trás-os-Montes (Zona Centro-Ibérica,Portugal) e sua correlação com Valongo e Buçaco. VII Cong. Nac.de Geologia, Univ. Évora, Livro de Resumos II, pp. 621–624. *Sousa, M. B., 1982 - Litostratigrafia e Estrutura do Complexo xisto grauváquico ante-Ordovícico - Grupo do Douro (NW de Portugal). Tese Univ. Coimbra, 222 p. *Teixeira, C. e Pais, J., 1973 - Sobre a presença de Devónico na região de Bragança (Guadramil e Mofreita) e de Alcañices (Zamora). Bol. Soc. Geol. Portugal, 18, pp. 199–202

External links

GePortal.LNEG.pt: InicioAzibo.org: Azibo Reservoir Protected Landscape website
{{DEFAULTSORT:Morais Ophiolite Complex Geology of Portugal Carboniferous Europe Permian System of Europe Geologic formations of Europe Ophiolites Suture zones

Geological uniqueness

See also

Notes

Sources

External links