US EPA

6880270 

Journal Article 

Marginal basin magmatism in an ancient volcanic arc: Petrology of the Palaeoproterozoic Mala-group basalts, Skellefte district, northern Sweden 

Bergstrom, U; , 

1997 

Yes 

G F F
ISSN: 1103-5897
EISSN: 1432-6264 

TAYLOR & FRANCIS LTD 

ABINGDON 

151-157 

WOS:A1997XH68400013 

A new stratigraphic unit, informally called the Mall group, is tentatively suggested for the interval between the are-related volcanic Skellefte and Arvidsjaur Groups in the western part of the Skellefte District. The Mala group comprises turbiditic greywackes and high-Mg basalts. The basalts vary from sills and lavas in the lower levels to mainly volcaniclastites at the top. The basalts contain characteristic actinolite pseudomorphs after pyroxene. Geochemically the basalts have high contents of Mg, Cr, and Ni and relatively high LIL elements. Tectonic discrimination using trace element geochemistry suggests a volcanic are setting. The geological setting is interpreted as a marginal basin formed at an advanced stage of the development of the Skellefte extensional continental margin are.