The Zhangbaling metamorphic belt and the Fucha Shan metamorphic zone are metamorphic terranes that occur along the Tan-Lu fault, the major strike-slip fault that separates the ultra-high-pressure metamorphic belts of Dabie Shan and Sulu in SE China. The greenschist-facies Zhangbaling metamorphic belt is characterized by subhorizontal foliation, belt-parallel lineation, and a top-to-south sense of shear; 40 Ar/ 39 Ar analysis of synkinematic white mica dates deformation at ca. 235–240 Ma, coeval with reported peak metamorphic ages of ultra-high-pressure metamorphism in Dabie Shan. The Fucha Shan metamorphic zone is composed of felsic to mafic mylonite and is characterized by subvertical foliation and subhorizontal lineation. Ductile fabrics record a sinistral sense of shear and provide evidence of a zone-perpendicular contraction. Fabric-forming biotites yield 40 Ar/ 39 Ar cooling ages of ca. 120 Ma to ca. 135 Ma. The lower-amphibolite-facies Fucha Shan zone may represent an Early Cretaceous transpressional shear zone that developed independent of the Zhangbaling belt. Alternatively, the Zhangbaling belt might have operated as an attachment zone coupling transpressional shear in the underlying Fucha Shan zone with brittle upper crustal deformation during Triassic movement on the proto–Tan-Lu shear zone. Deformation may have been associated with oblique convergence between South and North China. In this model, Early Cretaceous argon ages from the deeper Fucha Shan zone are thought to record a later exhumation event.

Four structural-metamorphic zones separated by ductile shear zones comprise the Sulu high- to ultrahigh-pressure metamorphic terrane. From south to north, they are the southern high-pressure zone (0.2–0.4 GPa, 350–400 °C), the central very high-pressure zone (1.5–2.5 GPa, 500–600 °C), the northern ultrahigh-pressure (UHP) zone (>2.8 GPa, 650–800 °C) dominated by paragneiss, and the northern UHP zone dominated by granitic gneiss. Exhumation was associated with retrograde amphibolite- to greenschist-facies metamorphism and oblique southeastward ductile extrusion within the subduction channel. Geologic observations and seismic reflection profiles suggest an eroded asymmetric antiformal slab intruded by numerous Mesozoic granitic plutons. Zircon U/Pb ages indicate that peak metamorphism in the UHP zone occurred at 240–220 Ma, and 40 Ar/ 39 Ar thermochronology documents later exhumation at 220–200 Ma. In contrast, in the high-pressure zone, peak metamorphism and exhumation ages are older than 253 Ma and 253–240 Ma, respectively, by the same mineral. Together with previous results, these new data suggest that subduction and exhumation of different parts of the Yangtze slab occurred at different times, depending upon vertical variations in the physical properties of the subducted continental crust.

The Haiyangsuo area of the NE Sulu ultrahigh-pressure terrane, eastern China, consists of gneisses with minor granulite and amphibolite layers, metagabbros, and granitic dikes. The peak-stage assemblages of the granulites (garnet + orthopyroxene + clinopyroxene + plagioclase ± pargasite ± biotite ± quartz) formed at >750 °C and 9–11 kbar and were overprinted by amphibolite-facies phases characterized by well-developed corona layers of | garnet | amphibolite + quartz | at contacts between plagioclase and clinopyroxene or orthopyroxene, as well as by the exsolution of (orthopyroxene + ilmenite + amphibole) from clinopyroxene. These textures indicate a near-isobaric cooling history of the granulite-bearing gneiss terrane. The metagabbro preserves a relict igneous assemblage (orthopyroxene + clinopyroxene + plagioclase + pargasite ± ilmenite ± quartz) in its core, but in its margins has a metamorphic corona texture similar to the granulite that formed at ∼600–700 °C and 7–10 kbar. Sensitive high-resolution ion microprobe (SHRIMP) U-Pb dating of zircons indicates that the protolith age of the garnetbiotite gneiss is older than 2500 Ma, whereas the granulite-facies metamorphism (the first regional metamorphic event) occurred at 1846 ± 26 Ma. Gabbro intrusion took place at 1734 ± 5 Ma, and the formation of amphibolite assemblages in both metagabbro and granulite occurred at ca. 340–370 Ma. Both gneiss and metagabbro were intruded by granitic dikes, with one dated at 158 ± 3 Ma. These data, together with a lack of eclogitic assemblages, suggest that this granulite-amphibolite–facies complex is exotic relative to the Triassic Sulu high-pressure–ultrahigh-pressure terrane; juxtaposition took place in Jurassic time.