Kanimblan Orogeny Kanimblan Orogeny The Kanimblan orogeny was a mountain-building event in eastern Australia toward the end of Early Carboniferous time (about 318 million years ago). It was a terminal orogenic episode forming the Lachlan Fold Belt, which was also known as the Lachlan Geosyncline before the advent of the plate tectonics theory. Uplift and deformation occurred in a 1,000 km belt extending from Tasmania to Cape York. However the original width was 2,000 to 3,000 km wide, with the excess size absorbed by folding and thrust faulting. The Kanimblan orogeny also affected the Tasman Geosyncline, which is aligned parallel with the
Sonoma orogeny arcs, composed of volcanic and volcaniclastic strata and paired geotectonically with Sonoma accretionary prisms to the east, are present in the Klamath-Sierran region of the Cordilleran orogen to the south of volcanic cover in the Pacific Northwest. Burchfiel and Davis presented a detailed model relating the Sonoma orogeny to convergent plate tectonic processes. They postulated an east-dipping subduction zone beneath a magmatic arc to the west of the continent. In this scheme, a back-arc basin floored by oceanic crust lay between the arc and the continent. The Sonoma orogeny involved closure of this basin and a process by which the