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Late Holocene volcanic stratigraphy and eruption chronology of the dacitic Young Doña Juana volcano, Colombia.
- Source :
-
Geological Society of America Bulletin . Sep2023, Vol. 135 Issue 9/10, p2510-2528. 19p. - Publication Year :
- 2023
-
Abstract
- We present the late Holocene eruption history of the poorly known Doña 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 reconstructed 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 transitions from lava-dome growth phases and collapse to explosive Vulcanian and possibly subplinian phases. Pyroclastic density currents were generated by dome collapse producing block-and-ash flows or by pyroclastic fountain/column collapse and were rapidly channelized into the deeply incised fluvial valleys around the volcano summit. The pyroclastic density currents were ~4-10 × 106 m3 in volume 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 (H/L) is higher for block-and-ash flows and dense lava-bearing fountain/lowcolumn-collapse pyroclastic density currents compared to pumice-bearing, column-collapse pyroclastic density currents. Associated mass-wasting processes included syneruptive and intereruptive debris flows, with the last one documented in 1936 CE. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00167606
- Volume :
- 135
- Issue :
- 9/10
- Database :
- Academic Search Index
- Journal :
- Geological Society of America Bulletin
- Publication Type :
- Academic Journal
- Accession number :
- 171448784
- Full Text :
- https://doi.org/10.1130/B36557.1