Sample WP-12

NavDat sample number 4779 · RHYOLITE

Sample

Sample ID	WP-12
Rock name	RHYOLITE
Rock type	VOLCANIC
Composition	FELSIC
Material	IGNEOUS
Comment	generally 98% aphanitic groundmass with tiny disseminated grains of magnetite; groundmass comprised of albite, quartz, and orthoclase along with small amounts of biotite flakes perfectly aligned to flow layering; some albite phenocrysts present; prominent macroscopic flow foliation

Latitude	44.4034
Longitude	-103.687
State / province	South Dakota
Volcanic field	Black Hills Tertiary igneous province

Age (Ma)	Error	Min	Max	Geologic age	Dated by
54		50	58

Item	Value	Unit	Method
SIO2	72.89	WT%	NAA
AL2O3	15.56	WT%	NAA
FE2O3	1.33	WT%	NAA
MGO	1.49	WT%	NAA
CAO	0.45	WT%	NAA
NA2O	3.71	WT%	NAA
K2O	4.21	WT%	NAA
TIO2	0.21	WT%	NAA
MNO	0.03	WT%	NAA
BAO	0.13	WT%	NAA
BA	1188.8	PPM	NAA
CE	34.7	PPM	NAA
CO	1.3	PPM	NAA
EU	1.2	PPM	NAA
HF	3.3	PPM	NAA
LA	19.2	PPM	NAA
LU	0.2	PPM	NAA
RB	65.3	PPM	NAA
SC	0.6	PPM	NAA
SM	3.6	PPM	NAA
TH	13.1	PPM	NAA
V	9.6	PPM	NAA
YB	1.3	PPM	NAA