TY  - JOUR
A1  - Engelhardt, Jonathan Franz
A1  - Sudo, Masafumi
A1  - Stockhecke, Mona
A1  - Oberhaensli, Roland
T1  - Feldspar Ar-40/(39) Ar dating of ICDP PALEOVAN cores
JF  - Geochimica et cosmochimica acta : journal of the Geochemical Society and the Meteoritical Society
N2  - Eleven inverse isochron ages from total fusion and three from stepwise heating analyses fit the age model. Four experiments resulted in older inverse isochron ages that do not concur with the model within 2 sigma uncertainties and that deviate from 1 ka to 17 ka minimum. C-and R-type zoning are interpreted as representing growth in magma chamber cupolas, as wall mushes, or in narrow conduits. Persistent compositions of PO-type crystals and abundant surfaces recording dissolution features correspond to formation within a magma chamber. C-type zoning and R-type zoning have revealed an irregular incorporation of melt and fluid inclusions. These two types of zoning in feldspar are interpreted as preferentially contributing either heterogeneously distributed excess Ar-40 or inherited Ar-40 to the deviating Ar-40/Ar-39 ages that are discussed in this study. (C) 2017 Elsevier Ltd. All rights reserved.
KW  - Lake Van
KW  - Feldspar zoning
KW  - Lacustrine record
KW  - Volcaniclastics
Y1  - 2017
U6  - https://doi.org/10.1016/j.gca.2017.07.039
SN  - 0016-7037
SN  - 1872-9533
VL  - 217
SP  - 144
EP  - 170
PB  - Elsevier
CY  - Oxford
ER  -