On the Heavy Mineral Zones in the Geosyncline Series. Recent Studies in the Northern Apennines, Italy

Abstract

ABSTRACT The order of appearance of the heavy minerals in the arenaceous formations of the Northern Apennines, in the light of the hypotheses by the different authors is here discussed. The gross composition and the texture of the sandstones indicate a provenance and a maturity which show no correlation with the heavy mineral assemblages. The post-depositional loss of the more unstable species, by intrastratal solution, is emphasized by the heavy mineral quantitative trends and corrosion structures. Such loss is only indirectly related to the age of the beds; other factors exert their strong influence, chiefly the burial depth and the stay duration below sea level. The order of appearance is uncomparable in different series, but is of considerable stratigraphic value in a single geosynclinal s ries.