Intervention of carbonate components in petrogenesis of the pyroxene nephelinites from the Jbel Saghro (Anti-Atlas, Morocco)

The Jbel Saghro alkaline complex was emplaced close to the eastern edge of the Moroccan Anti-Atlas. Within the northern part, two types of nephelinite were recognized [Ibhi and Nachit, 1999 and lbhi, 2000]. The first type (olivine-rich nephelinite) constitutes the main volcanic mass south of the Bou Gafer granit (fig. 1), where the volcanism had been active at least during 2 Ma, between 9.6 and 7.5 +/- 0.1 Ma [Berrahma et al., 1993]. The second group outcrops in the north (Foum El Kouss). It consists of pyroxene nephelinites which are younger (2.9 +/- 0.1 Ma) [Berrahma et al., 1993], and bears carbonatitic xenoliths, melteigitic pyroxenites and metasomatised peridotite xenoliths. Geochemically, the pyroxene nephelinite is highly enriched in LILE compared with the first one. The mineralogical and geochemical characteristics may be explained by the incorporation of carbonatitic and melteigitic pyroxenite segregates of carbonatitic affinity.

Kaupungit Itä- ja Pohjois-Suomen aluekehitysdynamiikan solmukohtina

English abstract: Urban regions as nodes of regional development in eastern and northeastern Finland

Maantieteellinen tieto ja valtiokehon rakentuminen: autonomian ajan Suomen Kartastot poliittisena toimintana

Abstract: Geographical knowledge and the production of the state body: the Finnish national atlases from the period of autonomy as political action

OECD:n tutkijaryhmä Suomen aikuiskoulutuksesta: Kärjessä kyllä ollaan, mutta epätasa-arvoisesti

Opetusneuvos Jorma Aholan haastattelu