depositional environments of the 3.0 ga. finlayson and lumby lake greenstone belts, superior province, ontario, canada
abstract
the finlayson and lumby lake greenstone behs are located approximately
200km west of thunder bay, ontario, nom of atikokan, ontario.
within both the finlayson lake and lumby lake grsenstom belts two distinct
sequences af sedimentary rocks are present. €a& of the belts contains an upper and a
lower sedimentary rocù sequence which differ in age and chernical composition-
the lower sequence of the finlayson lake greenstone belt is represented by
the little falls lake metasedimentary rocks and the laterally equivalent lower finlayson
lake rnetasedimentary rocks. these rocks consist of coarse-grained sandstones,
conglomerates, and lesser interbedded mafic detritusiich metasedimentary rocks and
are iaterally continwus with felsic volcanic rocks to the south. deposition of these
sedimentary rocks was by highdensity turbidity ainent processes. their chemical
composition is distinct from that of the upper finlayson lake metasedimentary rocks
and suggests a single felsic volcanic source with composition similar to that of the
steep rock upper felsic unit and the old tonalite unit.
collections
- retrospective theses [1604]