Late Holocene volcanic stratigraphy and eruption chronology of the dacitic Young Doña Juana volcano, Colombia

We present the late Holocene eruption his-tory of the poorly known Dona Juana volcanic complex, in SW Colombia, which last erupted in the twentieth century. This represents a case study for potentially active volcanism in the rural Northern Andes, where tropical climate conditions and a fragmented social memory blur the record of dormant volcanoes. We re-constructed the volcanic stratigraphy of the central-summit vent area by integrating new mapping at 1:5000 scale with radiocarbon ages, sedimentology analysis, and historical chronicles. Our results revealed cyclic transi-tions from lava-dome growth phases and col-lapse to explosive Vulcanian and possibly sub-plinian phases. Pyroclastic density currents were generated by dome collapse producing block-and-ash flows or by pyroclastic foun-tain/column collapse and were rapidly chan-nelized into the deeply incised fluvial valleys around the volcano summit. The pyroclastic density currents were similar to 4-10 x 106 m3 in vol -ume and deposited under granular flow- or fluid escape-dominated depositional regimes at high clast concentrations. In places, more dilute upper portions reached a wider areal distribution that affected the inhabited areas on high depositional terraces. The coefficient of friction (Delta H/L) is higher for block-and-ash flows and dense lava-bearing fountain/low-column-collapse pyroclastic density currents compared to pumice-bearing, column-col-lapse pyroclastic density currents. Associated mass-wasting processes included syneruptive and intereruptive debris flows, with the last one documented in 1936 CE.