The Kurosegawa Terrane is an anomalous, disrupted, Paleozoic and Mesozoic l
ithotectonic assemblage characterized by fragments of continent and contine
ntal margins. It is located in Southwest Japan where it lies between two Me
sozoic subduction complex terranes. The Kurosegawa Terrane is an exotic and
far-travelled geologic entity with respect to its present position. Limest
ones of the Kurosegawa Terrane formed along a continental margin yield fusu
linacean fossils Cancellina, Colania and Lepidolina. Accordingly, the Kuros
egawa Terrane was once situated within the Colania-Lepidolina territory in
the East Tethys-Panthalassa region at a palaeo-equatorial latitude, possibl
y close to the eastern margin of the South China and/or Indochina-East Mala
ya continental blocks. These blocks had rifted from Gondwana by late Devoni
an. They drifted northwards, passing through the Colania-Lepidolina territo
ry in mid-Permian time, and amalgamated with the proto-Asian continent duri
ng the late Triassic. Subsequently, during the Cretaceous, parts of the all
ochthonous continental blocks and their associated tectonic collage were tr
anspressed, dispersed, and displaced from the southeastern periphery of Asi
a towards the north. As a result, the Kurosegawa Terrane is formed as a dis
rupted allochthonous terrane, characterized by a serpentinite melange zone,
lying between the adjoining Mesozoic subduction complex terranes.