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The web of pegmatitic leucogranite gneiss inflates an undisrupted ghost stratigraphy of metamorphosed Neoproterozoic to Devonian carbonate and quartzite strata. Pegmatitic leucogranite makes up nearly half of the rocks within the mapped stratigraphic units. Emplacement environment for this peraluminous granite was an estimated 6–7 kb, >500°C. Compositions of the pegmatitic granite are consistent with derivation from muscovitedehydration melting of underlying Neoproterozoic pelitic rocks (Lee et al., 2003). Adjacent country-rock strata and their protoliths --metacarbonate rocks and quartzite, minor pelite--were not sources. The Zircons are Unusual • Mottled grain interiors + oscillatory zones. • Low T (600–700°). • Very high U (1000-15,000 ppm). • Very low Th/U (<0.01). • Hi U/Ce ratios. • Very high Hf, 13k-26k ppm. • Heavy-REE depleted. • Deep negative Eu anomalies. 113 92 Ma Multiple zircon ages between and within samples. 37 67 ~40 ~29 Precambrian xenocrysts, present in some other J, K & T granites in the area, are absent from the pegmatitic granite. 92 Ma 37 67 ~40 ~29 92 Ma 37 Instead we have antecrysts ?? (sort of). 67 ~40 ~29 SHRIMP UPb grain dates • Zircon U-Pb grain ages clustering at several ages between 92 and 68 Ma and between 42 Ma and 30 Ma indicate successive or rejuvenated igneous zircon growth multiple times over long periods of Late Cretaceous time and late Eocene to Oligocene times. We interpret clusters of zircon ages as times of new zircon growth in partial melt. Possible explanations of bimodal or multiple age ranges within and between samples: • Metamorphic overprints or Pb loss. Possible explanations of bimodal or multiple age ranges within and between samples: • Metamorphic overprints or Pb loss. • Composite ages across crystal zones. Possible explanations of bimodal or multiple age ranges within and between samples: • Metamorphic overprints or Pb loss. • Composite ages across crystal zones. • Samples are composites across heterogeneous intrusions. Possible explanations of bimodal or multiple age ranges within and between samples: • Metamorphic overprints or Pb loss. • Composite ages across crystal zones. • Samples are composites across heterogeneous intrusions. • Inherited grains present. Possible explanations of bimodal or multiple age ranges within and between samples: • Metamorphic overprints or Pb loss. • Composite ages across crystal zones. • Samples are composites across heterogeneous intrusions. • Inherited grains present. • Partial remobilization and recrystallization in situ. Pegmatitic granite forms networks of sills, sheets, and dikes. Coalesced pegmatitic granite intrusions intricately inject calc-silicate host rocks, isolating remnants of the metasediments. Host-rock remnants define undisrupted ghost stratigraphy and structure. Sheets of the white granite are more numerous low on canyon walls, including on the lower limb of a large fold nappe. The increased percentage of granite at lower structural levels is interpreted to reflect more advanced stages of incremental assembly of the batholith. Based on the ghost stratigraphy and intrusive style, the batholith was assembled incrementally by myriads of small intrusions. As the intrusions coalesced, boundaries became blurred. Do the multiple U-Pb ages represent new magma injections from depth? Or could they represent slight remobilizations at or near the observed site of intrusion? Folded sills that merge with cross-cutting dikes are consistent with remobilization of preexisting intrusive bodies. SUMMARY Low-temperature hydrous granites were emplaced incrementally into host rocks without major disruption of host-rock structure. Zircons show large age ranges suggestive of multiple episodes of remobilization in partial melts. Fluxes of hydrous fluids? These processes extended from ~93 Ma to 68 Ma and ~40Ma to 30 Ma. Intrusion style and SHRIMP geochronology for this plutonic complex in the Ruby Mountains core complex suggest very lengthy construction and reconstruction of a batholith-sized volume by incremental coalescence of small intrusions.