110 Chemical Analyses of Basalts

The Geology and Petrography of Crater Lake National Park, 1902

 PART II.

BASALTS.

CHEMICAL ANALYSES OF BASALTS.

The following analyses were made in the United States Geological Survey laboratory:

Analyses of Crater Lake basalts.
[Analyses by H. N. Stokes.]

  158. 173. 189.
SiO2 56.95 52.99 58.65
Al2O3 18.84 16.71 18.35
Fe2O 2.06 3.80 1.59
FeO 4.28 3.55 4.21
MgO 4.37 6.95 3.49
CaO 7.45 8.49 6.95
Na2O 3.89 3.56 3.70
K2O .82 1.29 1.32
H2O- .19 .18 .20
H2O+ .31 .59 .70
TiO3 .79 1.18 .81
ZrO2 —- None. —-
CO2 None. None. None.
P2O5 .19 .42 .17
SO3 —- None None.
Cl —- Trace. —-
F —- Undet. —-
S Trace. None. None.
Cr2O3 None. None. None.
NiO —- .02 —-
MnO Trace. Trace. Trace.
BaO .04 .07 .06
SrO Trace. .12 Trace.
Li2O None. None. None.
   Total 100.18 99.92 100.20
NOTE.—O=Cl.No. 158. A hypersthene-bearing basalt of the interstitial type, from Anna Creek. See page 145.

No. 173. Hypersthene-bearing basalt, porphyritic interstitial type, transitional to the andesitic type, from the base of Red Cone. See page 155.

No. 189. A hypersthene—bearing basalt of the andesitic type, from north of Desert Cone. This rock is doubtfully placed among the basalts, based upon structural and geological relationships. See page 160.

 

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