PANGAEA_874334 Major elements, trace elements and Sr-Nd-Pb isotopes form lavas of lakes Nyos, Wum, Elum and Oku sampled in the Oku Volcanic Group of the Cameroon Volcanic Line Asaah, Asobo N E; Yokoyama, Tetsuya; Aka, Festus T; Usui, Tomohiro; Kuritani, Takeshi; Wirmvem, Mengnjo J; Iwamori, Hikaru; Fozing, Eric M; Tamen, Jules; Mofor, Gilbert Z; Ohba, Takeshi; Tanyileke, Gregory; Hell, Joseph Victor Major elements, trace elements and Sr-Nd-Pb isotopes form lavas of lakes Nyos, Wum, Elum and Oku sampled in the Oku Volcanic Group of the Cameroon Volcanic Line 2017-04-06 PANGAEA Dataset https://doi.pangaea.de/10.1594/PANGAEA.874334 Investigator Asobo N E Asaah asoboasaah@gmail.com Earth Science Event label Latitude of event Longitude of event Sample ID Silicon dioxide Titanium dioxide Aluminium oxide Iron oxide, Fe2O3 Manganese oxide Magnesium oxide Calcium oxide Sodium oxide Potassium oxide Phosphorus pentoxide Loss on ignition Total Magnesium Chromium Nickel Cobalt Vanadium Zinc Copper Rubidium Strontium Yttrium Zirconium Niobium Caesium Barium Lanthanum Cerium Praseodymium Neodymium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Lead Thorium Uranium Strontium-87/Strontium-86 ratio Neodymium-143/Neodymium-144 ratio Lead-206/Lead-204 ratio Lead-207/Lead-204 ratio Lead-208/Lead-204 ratio geoscientificInformation OVG_Lake_Elum OVG_Lake_Nyos OVG_Lake_Oku OVG_Lake_Wum Sampling by hand Complete 6.192778 6.44505 10.2069 10.453889 unrestricted CC-BY-3.0: Creative Commons Attribution 3.0 Unported English PANGAEA Data Publisher for Earth & Environmental Science https://www.pangaea.de/ Data Center Contact Michael Diepenbroek info@pangaea.de

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Bremen Bremen 28359 Germany online 1768 data points text/tab-separated-values Asaah, Asobo N E; Yokoyama, Tetsuya; Aka, Festus T; Usui, Tomohiro; Kuritani, Takeshi; Wirmvem, Mengnjo J; Iwamori, Hikaru; Fozing, Eric M; Tamen, Jules; Mofor, Gilbert Z; Ohba, Takeshi; Tanyileke, Gregory; Hell, Joseph Victor (2015): Geochemistry of lavas from maar-bearing volcanoes in the Oku Volcanic Group of the Cameroon Volcanic Line. Chemical Geology, 406, 55-69, https://doi.org/10.1016/j.chemgeo.2015.03.030

Lake Nyos is located at the summit of a stratovolcano in the Oku Volcanic Group (OVG) along the Cameroon Volcanic Line. The sudden release of magmatic CO2 trapped at the bottom of Lake Nyos in August 1986 caused historical casualties of 1750 people and over 3000 cattle. New geochemical data of volcanic rocks from the Nyos volcano and the first available data for volcanic rocks from other maar-bearing volcanoes (Lakes Elum, Wum and Oku) in the OVG are presented and compared. Lavas from the Nyos, Elum and Wum volcanoes show similarities in major and trace elements and Sr?Nd?Pb isotopes, suggestive of a similar mantle source. However, this source is slightly different from that of the Oku volcano. The samples from Lake Oku have lower alkali, higher TiO2 and more depletion and enrichment in most incompatible trace elements than those from the Nyos, Elum and Wum volcanoes. These differences and those observed in the Sr?Nd?Pb results are consistent with a heterogeneous source for lavas in the OVG. Trace element compositions suggested the presence of garnet in the source (< 6% garnet) and modelled melting results indicate < 2% partial melting of the source material. Isotope data plot within the focal zone, extending towards enriched mantle 1 (EM1; e.g. Lakes Oku and Nyos samples). This indicates the involvement of at least three mantle components: depleted mid-ocean ridge basalt mantle, high-µ and EM1 components in the magmatism of the lavas studied. The contributions of these components in different proportions, originating from asthenospheric and subcontinental lithospheric mantle sources, can account for the observed variations in geochemical characteristics. The geochemical characteristics of the studied lavas indicate that the magma source need not necessarily have an abnormal CO2 concentration to pose a potential threat. Degassing of an ordinary magma chamber and the migration of gas to the bottom of the lakes through cracks and faults can lead to the accumulation of CO2 in lake bottoms. This is controlled by tectonic parameters (fractures and faults) that enhance degassing from the magma chamber to the lake bottom and physical parameters of the lake (e.g. size, depth, temperature and solubility) that control CO2 stability. ** For all details see the full metadata description at "https://doi.pangaea.de/10.1594/PANGAEA.874334"!

http://en.wikipedia.org/wiki/Loss_on_ignition Loss on ignition https://doi.org/10.1016/j.chemgeo.2015.03.030 Geochemistry of lavas from maar-bearing volcanoes in the Oku Volcanic Group of the Cameroon Volcanic Line https://en.wikipedia.org/wiki/Calcium_oxide Calcium oxide https://en.wikipedia.org/wiki/Silicon_dioxide Silicon dioxide https://en.wikipedia.org/wiki/Titanium_dioxide Titanium dioxide DIF 9.4 2017-04-06 2026-07-15