Sample 12

NavDat sample number 5461

Sample

Sample ID	12
Rock type	VOLCANIC
Material	IGNEOUS

Location

Latitude	23.975
Longitude	-104.75
Location	Durango City
State / province	Durango
Formation	Tunal Formation

Age

Age (Ma)	Error	Min	Max	Geologic age	Dated by
31.2		30.5	31.9

Analyses

Whole Rock

Item	Value	Std. dev.	Unit	Method
SIO2	73.8		WT%	UNKNOWN
TIO2	0.21		WT%	UNKNOWN
AL2O3	13.45		WT%	UNKNOWN
FE2O3	1.6		WT%	UNKNOWN
FEO	0.28		WT%	UNKNOWN
MNO	0.02		WT%	UNKNOWN
MGO	0.24		WT%	UNKNOWN
CAO	0.77		WT%	UNKNOWN
NA2O	3.27		WT%	UNKNOWN
K2O	4.36		WT%	UNKNOWN
H2O_PLUS	0.92		WT%	UNKNOWN
H2O_MINUS	0.38		WT%	UNKNOWN
P2O5	0.05		WT%	UNKNOWN
CO2	0.01		WT%	UNKNOWN

References

Swanson, E R; Keizer, R P; Lyons, J I; Clabaugh, S E (1978) Tertiary volcanism and caldera development near Durango City, Sierra Madre Occidental, Mexico. Geological Society of America Bulletin, vol.89, no.7, pp.1000-1012, Jul 1978 doi:10.1130/0016-7606(1978)89<1000:TVACDN>2.0.CO;2