Evidence for the ∼ 1.4 Ga Picuris orogeny in the central Colorado Front Range

We present the first evidence for sedimentation and new penetrative deformation metamorphism in central Colorado Front Range associated with ∼ 1.48–1.35 Ga Picuris orogeny. This orogeny has recently been recognized New Mexico, Arizona southern may be part of a larger active accretionary margin that includes 1.51–1.46 Pinware Baraboo events, eastern Canada US respectively, preceded amalgamation Rodinian supercontinent. demonstrate addition to 1.4 reactivation northeast-trending Paleoproterozoic shear zones, regional folding occurred an area south Mt. Evans, away from these zones. Detrital zircon one quartzite yielded U–Pb laser ablation inductively coupled mass spectrometry (LA-ICPMS) major age populations 1.81–1.61 1.49–1.38 Ga, minor ones 1.90 1.56 Ga. The have numerous local sources. population represent exotic as Defiance, Yankee Joe Blackjack Formations Arizona, Four Peaks Tusas Mountains Mexico. Alternatively it result mixing between domains reflecting older younger populations, or Pb loss 1.81 1.61 zircon. In-situ LA-ICPMS analysis on monazite four biotite schist samples 1.74 1.42 separate show 1.68–1.47 1.39–1.33 spreads. detrital metamorphic. Monazite ages 1.6 1.5 due loss, because during time not Laurentia. are most likely metamorphic consistent sedimentation, especially indicate impact extent southwestern U.S. than previously thought.