Pál Molnár, Elemér

English

During the ISO years the syenite massif of Ditró has been examined by excellent mineralogists and petrographer s like HERBICH (1872); KOCH (1880); BERWERTH (1905); REINHARDT (1911); MAURITZ (1909-25) ; JANOVICI (1932,1934,1970) ; STRECKEISEN (1931-74) ; CODARCEA etal. (1957); ANASTASIU and CONSTANTINESCU (1979-81) ; JAKAB (1976,1982,1986) . Magmatic mass of the massif penetrates the metamoiphic rocks of the Tölgyes Series and the Rebra-Barnar Series and the Bretila Series (i.e. Rarau Gneisses and Hagymás Granitoides). Certain parts of the massif are covered by Pliocene limnic sediments (JEKEL1US 1923), Late Pliocene-Early Quaternary gravels (STRECKEISEN 1952) and agglomerates and tuffs as well as the lava layer of the Kelemen-Hargita volcanic range (JANOVICI 1934; SAVUL and KRAUTNER 1937; RADULESCU et al. 1973 ) {Fig. 1). According to our present knowledge the age of the Ditró syenite massif is between 150—160 and 120—13 0 My . (BAGDASARIAN 1972 ; STRECKEISEN and HUNZDCER 1974 ; MINZATU 198 2 and JAKAB 1982). On the basis of their spatial setting and structure and their petrochemistry as well as relationships to each other, the rocks of the Ditró syenite massif can be divided into several groups. A wide range of variety of the rocks located into a fairly small area suggests different intrusions. Their alkaline character can be attributed to the results of several alkaline-metasomatic phases which touched not only the magmatic-metamorphic complexes found within the massif, but the surrounding rocks, too. Outcropping of the homblendites in the basin of the Orotva creek (northern part of the massif) takes a distinctive importance among these groups of rocks. According to the recent — but not proved — theory (JAKAB 1986) the homblendites are originated by Fe and Mg metasomatism of earlier crystalline rocks which elements derived from the adjacent alkaline environment. It is obvious that further petrological investigations need for the correct genetical estimation of the Orotva creek homblendites

Pál Molnár Elemér

University of Szeged

Petrographical characteristics of Ditro (Orotva) hornblendites, Eastern Carpathians, Transylvania (Romania) : a preliminary description

http://acta.bibl.u-szeged.hu/24803/1/mineralogica_033_067-080.pdf

Petrographical characteristics of Ditro (Orotva) hornblendites, Eastern Carpathians, Transylvania (Romania) : a preliminary description

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University of Szeged