Beschreibung/Abstract top ↑
 A near-shore continental rift or back-arc basin with strong bathymetric variation must have existed from the Upper Devonian to the middle Lower Permian along the present Lancang River Zone. The extension phase, which led to the creation of the basin, is in time and facies related to the expanding continental margin of the Yangtze Platform in the Devonian and Lower Carboniferous. During the rifting phase, basic to acid volcanic rocks were extruded in a submarine environment to form small-scale Kuroko-type volcanic-hosted massive sulfide (VHMS) deposits.
 Characterized by an eastward progressing deformation front, closure of the basin began in the Upper Carboniferous and progressed from present west to east. This closure was associated with the formation of an accretionary wedge on the west side, in which the volcanogenic-hosted massive sulfide deposits were sheared. From this belt to the present west, the deformation increases parallel to the gradual change from greenschist- (Phyllite Belt) to lower blueschist facies (Lancang Group) documenting a large-scale thrust belt or accretionary wedge. The closure of the basin led to the exhumation of the blueschist- and greenschist- metamorphosed rocks and the formation of a land area on the western edge of the Yangtze Platform up to the Middle Permian.
 Late Paleozoic orogenesis was followed by marine ingressions, post-orogenic bimodal rift volcanism and continental sedimentation. The continental volcanism is an expression of a regional thermal event causing crustal anatexis and the formation of the Lincang Granite. The petrology and geochemistry of the Permo-Triassic basalts along the Lancang River correspond to the continental flood basalts of the Emeishan Large Igneous Province (LIP), which are probably mantle-plume related. Hence, the new plate tectonic model excludes a Mesozoic island-arc setting and expectations of finding large-scale Au-bearing porphyry copper deposits cannot be met. Nevertheless, a close correlation between the volcanic rocks along the Lancang River and the Emeishan flood basalts (and rhyolites) opens up a new perspective: Ore deposits in relation to large scale continental rifting, such as i] Native Cu-deposits of Keweenaw-type (Keweenaw rift, Precambrian, Superior Province, Canada), ii] Ni-Cu-PGE deposits of Norilsk-Talnakh-type, Siberian Traps, or iii] Volcanic red-bed Cu-deposits.
 In the Upper Triassic, weak compression and basin inversion took place along the Lancang River Zone. The cause of this compression is unclear but could be associated with the collision of the Tengchong micro-continent further to the west.
 A regional extensional phase took place from the Upper Jurassic to the Paleogene, and the exhumation of the Lincang Metamorphic Core Complex controlled the deposition of massive sequences of continental red-beds in the Simao Basin.
 If the mechanics forming the Simao Basin are fundamentally correct, the local consequence for western Yunnan is that a middle Cenozoic inversion of the +Simao Basin must have been largely accommodated by the readjustment of formerly extensional allochthons, which progressively led to a complex interplay of thrusting, folding, faulting and rotation. During this period a whole spectrum of mineralization developed as a result of the high fluid flow in the transtensional settings of the India-Asia collision in West Yunnan. Copper porphyries occur in addition to polymetallic vein mineralization and Au-quartz veins.