Has the Yangtze craton lost its root? A comparison between the North China and Yangtze cratons

• A comprehensive study reveals that the Yangtze craton has lost part of its root.
• A comparison of two cratons reveals a common three stage root-loss mechanism.
• The first stage is regional weakening/thinning/modification of the lithosphere.
• The second stage is lithospheric delamination caused by slab subduction and rollback.
• The third stage is further destruction of the lithosphere via thermo-chemical erosion.

A review and comparison of the tectonic history and lithospheric structure of the Yangtze craton and North China craton (NCC) are made to test whether the Yangtze craton has lost part of its lithospheric root like the NCC has, and if so, is there a common driving tectonic force for root-loss. The results show that many similarities and some significant differences exist between these two cratons. The similarities include the following: (1) The eastern parts of the NCC and Yangtze craton have both been destroyed. The destroyed areas are bounded on the west by the North–South Gravity Lineament. (2) Fast velocity bodies located above depths between 200 and 400 km are detected beneath the NCC and Yangtze craton, implying that delamination may be an important mechanism of cratonic destruction for these two cratons. (3) The destruction of the NCC and Yangtze craton can be divided into several stages. The differences mainly lie in the tectonic evolution during Neoproterozoic-early Mesozoic. The tectonothermal events which are beneficial for the lithospheric weakening of the NCC dominantly affected the marginal regions. However, for the Yangtze craton, they are not only limited to the marginal regions, but also extend to the eastern and middle parts of the craton. This may be a key factor why the Yangtze craton shows more continuous slow velocity anomalies.We also make a study on the time and dynamic mechanism of the destruction of the Yangtze craton. The results show that the initial destruction started in the Neoproterozoic and may be caused by the aggregation and breakup of Rodinia. The large scale destruction occurred mostly in the Mesozoic (190–90 Ma) with a peak time of 130–120 Ma. The subduction and rollback of the Paleo-Pacific (Izanagi) plate may play a vital role in the destruction of the Yangtze craton.

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