V43B-3114
New Constraints on the Geochemistry of the Millennium Eruption of Mount Paektu (Changbaishan), Democratic People’s Republic of Korea/China
Thursday, 17 December 2015
Poster Hall (Moscone South)
Kayla Iacovino1, Ju Song Kim2, Thomas W Sisson1, Jacob B Lowenstern1, Jong Nam Jang2, Kun Ho Song2, Hong Huan Ham2, Kuk Hun Ri3, Amy R Donovan4, Clive Oppenheimer4, James O S Hammond5, Kosima Weber Liu6 and Kum Ran Ryu7, (1)USGS, Menlo Park, CA, United States, (2)Earthquake Bureau, Pyongyang, North Korea, (3)State Scientific Academy, Pyongyang, North Korea, (4)University of Cambridge, Cambridge, United Kingdom, (5)Imperial College London, London, United Kingdom, (6)Environmental Education Media Project, Beijing, China, (7)Pyongyang International Information Center of New Technology and Economy, Pyongyang, North Korea
Abstract:
Mount Paektu (also known as Changbaishan) is a large caldera located on the border between China and the Democratic People’s Republic of Korea. Circa 946 AD, Paektu produced one of the largest volcanic eruptions in recorded history, the so-called Millennium Eruption (ME), whose combined fall and pyroclastic flow deposits total approximately 25 km3 dense rock equivalent (95% commendite, 5% late stage trachyte). Despite its recent and potentially destructive history, the volcano is not well studied due to its relative inaccessibility. A seismic swarm beneath the volcano’s summit in 2002-2005 spurred a unique collaboration between scientists from the DPRK, US, and the UK with the goals of characterizing Paektu’s eruptive history and assessing its current state of activity. We present new results from this collaboration, including major and trace element (XRF, EMP and SHRIMP-RG) and volatile data (SHRIMP-RG and FTIR) on feldspar-, clinopyroxene-, and olivine-hosted melt inclusions (MI), matrix glasses, and bulk pumices from four ME comendites and one ME trachyte. MI are halogen rich (F≤4000 ppm, Cl≤5000 ppm) with moderate S (≤250 ppm) and H2O (≤4 wt%) and minimal CO2 (≤15 ppm, detection limit ~2 ppm). H2O contents in comendite MI indicate saturation pressures (at 725 °C) of ~150 MPa, corresponding to a magma chamber depth of ~6 km, similar to the depth inferred for the magmatic injection thought to have resulted in the 2002-05 earthquake swarm. ME comendite is consistent with a ca. 25% residual melt by fractional crystallization from an ME trachyte parent. Published U-series zircon ages from ME comendite indicate a magma residence time of 11ky. Thus, the late stage ME trachyte likely represents a mafic recharge event of a melt separate from but geochemically similar to the original ME comendite parent.
