Recognizable primary volcanic and sedimentary features in a low-strain domain of the highly deformed, oldest known (approximate to 3.7-3.8 Gyr) Greenstone Belt, Isua, West Greenland

A low-strain domain has been identified in the metamorphosed, mostly highly deformed volcanic and sedimentary rocks of the early Archaean Isua supracr ustal belt. This domain contains well-preserved volcanic and sedimentary fe atures, including basaltic pillow lavas, pillow breccia, heterogeneous volc anic breccia, amygdules in metabasalt, and polymict conglomerate dominated by recrystallized chert and volcanic clasts. The low-strain domain is bound ed by highly deformed rocks mostly derived from basalt, chert, and banded i ron formation. These discoveries demonstrate that some primary features hav e escaped the pervasive metasomatism dominant in other parts of the belt an d, furthermore, strengthen the characterization of the Isua supracrustals a s a typical greenstone belt.