Skarn-mineralized porphyry adakites in the Harlik arc at Kalatage, E. Tianshan (NW China): Slab melting in the Devonian-early Carboniferous in the southern Central Asian Orogenic Belt

•Porphyry deposits closely associated with adakitic diorite porphyries (382–390Ma).•Adakites most likely formed by melting of a young/hot subducted oceanic slab.•Southward migration defined for the Harlik-Dananhu arc from 390Ma to 322Ma.•Hot oceanic crustal slab contributes to crustal growth and mineralization in CAOB.