Post-Meeting Field Trip 2

Meso-Cenozoic tectonics in the Daqingshan orogen, North China 

Time Duration：25-28, October,2024 

Leader:  Prof. SHI Wei, Chinese Academy of Geological Sciences (CAGS) 

Major cities or towns on the line:  Beijing City (start), Ulanchap City, Hohhot City, Baotou City, Beijing City (end) 

Geological features for observation and investigation:
     1. Pleistocene volcanoes to the north of Ulanchap City show lithospheric destruction in the Quaternary;
     2. The Middle Jurassic growth strata to the Baotou city constituted a roughly forward thrusting sequence with a slow uplift rate in the early stages and a suddenly accelerated uplift rate in the final stage, responding to the initiation of Yanshanian deformation during 170–160 Ma due to N-S compression driven by the closure of the Mongol-Okhotsk Ocean.
     3.The Hohhot “MCC” to the north of Hohhot City, records top-to-southeast normal-sense exhumation of the deformed Archean-Proterozoic metamorphic basement that was intruded by Jurassic-Cretaceous complex granite mass. The basement was intruded by deformed Jurassic adakitic and undeformed Cretaceous A-type intrusions in the footwall. The mylonitic shear zone (S1) located between undeformed Cretaceous granite and low-angle detachment faults with pervasively top-to-SE simple shearing (ca. 146-141 Ma). Here the three units composed the Hohhot “MCC” and reestablished Hohhot thermal upwelling-extensional structure (TUES) model: (a) the core-granite composed of Early Cretaceous (136-127 Ma) A-type granites; (b) the pure-shear-dominated shear zone (S21) distributed in the core-granite periphery, with foliation (no lineation); (c) the low-angle detachment system (S22) characterized by low-angle normal faults separating the footwall top-to-the-SE ductile structures and microbreccia zone from the hanging-wall Cretaceous supra-detachment basin along the flank of domal S1. 

Costs: 3200 CNY per-person, which covers：
     1. Hotel stay (4 nights stay in the on Ulanchap City, Hohhot City, and Beijing City, respectively, on 25th-28th October 2024), meals and water in the field.
     2. Field vehicle rental/gasoline/toll.
     3. Administrative fees for preparing and setting up the field trip.
     4. Fees for entering private properties during the field excursion without sightseeing, etc.