Katana VentraIP

South China Craton

The South China Craton or South China Block is one of the Precambrian continental blocks in China.[1] It is traditionally divided into the Yangtze Block in the NW and the Cathaysia Block in the SE.[2] The Jiangshan–Shaoxing Fault represents the suture boundary between the two sub-blocks.[2] Recent study suggests that the South China Block possibly has one more sub-block which is named the Tolo Terrane.[3] The oldest rocks in the South China Block occur within the Kongling Complex, which yields zircon U–Pb ages of 3.3–2.9 Ga.[1]

There are three important reasons to study the South China Block. First, South China hosts a great deal of rare-earth element (REE) ores. Second, the South China Block is a key component of the Rodinia supercontinent. Therefore, such study helps us understand more about the supercontinent cycle. Third, almost all major known clades of Triassic marine reptiles have been recovered from the South China sedimentary sequences.[4] They are important to understand the marine recovery after the Permian-Triassic mass extinction.[5]


The South China Block was formed by collision between the Yangtze Block and Cathaysia Block in the Neoproterozoic. On the one hand, the central and eastern part of the South China Block experienced three important Phanerozoic tectonic events. In the Chinese literature, they are named the Wuyi-Yunkai Movement (Early Paleozoic), the Indosinian Movement (Triassic) and the Yanshanian Movement (Jurassic-Cretaceous). They led to extensive deformation and magmatism.


On the other hand, the Late Paleozoic Emeishan flood basalt magmatism is an important event in the western part of the block.

Sedimentary rocks show a greater population of 2.1-1.8 Ga detrital zircons.

[14]

The age of the oldest igneous rock coincides with the time of final assembly of the supercontinent (e.g. 1.89–1.86 Ga S-type granitoids in Badu Complex).[14]

Columbia

The timing of amalgamation is unclear.[17][19][20][21][22][23]

[18]

The process of amalgamation is uncertain.[24][25][26][27]

[21]

The genesis of the Neoproterozoic (830—740 Ma) post-collision magmatism is unclear.[28][29][30][31][32][33][34][35]

[22]

The position in the supercontinent is controversial.[17][29][32][33][34][36][37][38][30][39]

Rodinia

Crustal thickening by folding and thrusting occurred, but there is considerable doubt on the overall deformation features.

[2]

There is widespread Silurian (440–415 Ma) granitic intrusion.[44][45][46] The granitic rock includes biotite monzonitic granite and muscovite-, garnet-, and tourmaline-bearing granites.[2][44][45][46] The source of the granitic rock was probably pre-existing crustal material instead of a mantle-derived component, as evidenced by a highly negative epsilon Nd value.[2][3][44]

[2]

The rock experienced upper greenschist to amphibolite-facies metamorphism (i.e. 460–445 Ma), which is earlier than the granitic intrusion.

[47]

The Pressure-Temperature curve of the metamorphic rock shows a clockwise curve. This indicates crustal thickening.

[47]

Large scale Early to Middle Carboniferous deformation event (i.e. folding and thrusting). This indicates a major collision event.

[59]

Pre-middle Carboniferous on either side of the Song Ma zone are different while the Middle Carboniferous faunas are similar.[59] This reveals a juxtaposition between the South China Block and Indochina block.

faunas

Mineral resources[edit]

The most important mineral resources in the South China Block must be the rare earth element (REE). REEs have a very wide range of application.[65] Nowadays, China accounts for more than 80% of the global REE production.[66] A lot of weathering-related REE deposits are found in South China such as the Zudong deposit and the Guposhan deposit in Jiangxi and Guangxi province respectively.[66]


When the rare earth element-enriched felsic magma cools down to become rock, intense weathering of the rock further concentrates the rare earth element deposit.[65] Therefore, the property of magma and the weathering intensity is the key to concentrate the rare earth element deposits. In South China, 75% of these deposits were derived from granitic and volcanic rocks during the Jurassic to the early Cretaceous.[65] Therefore, the Yanshanian Movement represents one of the vital geological events in South China.[65]

China University of Geosciences

Chinese Academy of Geological Sciences

Chinese Geological Formations

Columbia

Detrital zircon geochronology

North China Craton

Rodinia