Sample 228

NavDat sample number 88035 · RHYODACITE

Sample

Sample ID	228
Rock name	RHYODACITE
Rock type	VOLCANIC
Composition	FELSIC
Material	IGNEOUS
Collected by	Hildreth and others
Comment	Dome with 250 m relief, intrudes and overlies ignimbrite near south-central margin of caldera

Location

Latitude	48.8108
Longitude	-121.728
Location	Oreamnos Dome
State / province	Washington

Age

Age (Ma)	Error	Min	Max	Geologic age	Dated by
1.127		1.116	1.138

Analyses

Whole rock

Item	Value	Std. dev.	Unit	Method
SIO2	69		WT%	XRF
TIO2	0.55		WT%	XRF
AL2O3	16.19		WT%	XRF
FEOT	1.75		WT%	XRF
MNO	0.04		WT%	XRF
MGO	1.07		WT%	XRF
CAO	3.48		WT%	XRF
NA2O	4.51		WT%	XRF
K2O	2.71		WT%	XRF
P2O5	0.29		WT%	XRF
LOI	1.19		WT%	XRF
TOTAL	97.83		WT%	XRF
RB	54		PPM	XRF
SR	660		PPM	XRF
Y	16		PPM	XRF
ZR	198		PPM	XRF
BA	1000		PPM	XRF
CE	53		PPM	XRF
V	36		PPM	XRF

References

Hildreth, Wes; Lanphere, Marvin A; Champion, Duane E; Fierstein, Judy (2004) Rhyodacites of Kulshan Caldera, north Cascades of Washington;post-caldera lavas that span the Jaramillo. Journal of Volcanology and Geothermal Research, vol.130, no.3-4,pp.227-264, 29 Feb 2004 doi:10.1016/S0377-0273(03)00290-7