Rhyolitic ignimbrites, in contrast, reveal complex zoning patterns, reflecting several episodes of partial resorption and growth throughout their crystallization history. Resorption textures are rare, and hence crystals in rhyolitic lava flows recorded a simple, rapid extraction, transport and eruption history for these crystal-poor melts. Quartz crystals from rhyolitic lava flows display simple oscillatory cathodoluminescence (CL) zoning interpreted to be magmatic and diffusion chronometry suggest a short timescale for quartz crystallization from 5.6 ± 2.2 to 41.6 ± 9.8 years. The textural and geochemical analysis revealed clear differences between crystal-poor rhyolitic lava flows and crystal-rich rhyolitic ignimbrites. Quantitative Ti-data were acquired by SIMS to estimate crystallization temperatures. The timescales are assessed by using diffusion modeling based on nanoscale secondary ion mass spectrometry (NanoSIMS) analysis of titanium (Ti) concentration profiles in quartz crystals oriented by image analysis using micro-tomography. We compare quartz zonation and diffusion timescales of crystal-rich rhyolitic ignimbrites and crystal-poor rhyolitic lava flows from the Jurassic Chon Aike Province exposed in Patagonia (Argentina). Textural and chemical differences in coeval rhyolitic effusive and explosive eruptions are commonly observed, and numerical models predict different timescales for the eruption of crystal-rich mushes versus crystal-poor magmas.