AVO Sample Information

Alaska Volcano Observatory

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SAMPLE INFO : 268

Sample ID:	268
Station ID:	268
Latitude:	55.19
Longitude:	-160.5
Datum:	NAD83
Date Sampled:	1895-01-01
Sample Type 1:	Lava
Field Lithology:	Andesite

Text Description:
An andesite from Delarof Harbor, near which the Apollo mine is situated, forms in some respects a transition between the lava of St. Augustine and the more usual type of pyroxene-andesites. It is a greenish-black, somewhat vesicular porphyry, in which the microscope shows phenocrysts of augite, a rhombic pyroxene, which in this case seems to be enstatite rather than bronzite, and labradorite. The groundmass consists of "felted" feldspar microlites, a little augite, a little magnetite, and a considerable amount of glass. The feldspathic microlites are mainly alkaline labradorite, while the phenocrystic crystals are more calcareous, approaching Ab3 An4; but some of the microlites have angles of extinction appropriate to oligoclase. The slide shows decomposition products, especially chlorite, but not in important quantities.

References:

Reconnaissance of the gold fields of southern Alaska with some notes on general geology

GEOCHEM DATA

StationID	Latitude	Longitude	Geologist	DateVisited	Age Info	Volcano	Eruption	Location Description	Text Description	Sample ID	Sample Type 1	Sample Type 2	Final Unit	Material	SiO2	TiO2	Al2O3	FeOT	MnO	MgO	CaO	Na2O	K2O	P2O5	Total-majors	REF majors	METH majors	Fe2O3/Fe203T orig	FeO/FeOT orig	Volatiles csv	METH volatiles	Cs	Rb	Ba	Sr	La	Ce	Pr	Nd	Sm	Eu	Gd	Tb	Dy	Ho	Er	Tm	Yb	Lu	Y	Zr	Nb	Hf	Ta	Pb	Th	U	Sc	V	Cr	Fe	Co	Ni	Cu	Zn	Ga	Mo	As	Na	K	Ref trace1	METH trace1	Rb	Ba	Sr	La	Ce	Nd	Sm	Eu	Gd	Dy	Er	Yb	Lu	Y	Zr	Nb	Pb	Th	U	Sc	Ti	V	Cr	Ni	Cu	Zn	Ga	Ref trace2	METH trace2	Light csv	Halogen csv	other major csv	other lile csv	other ree csv	other hfse csv	other hpe csv	other tm csv	other misc csv
268	55.19	-160.5	Becker, G. F.	1895-01-01				Delarof Harbor, Unga Island	An andesite from Delarof Harbor, near which the Apollo mine is situated, forms in some respects a transition between the lava of St. Augustine and the more usual type of pyroxene-andesites. It is a greenish-black, somewhat vesicular porphyry, in which the microscope shows phenocrysts of augite, a rhombic pyroxene, which in this case seems to be enstatite rather than bronzite, and labradorite. The groundmass consists of "felted" feldspar microlites, a little augite, a little magnetite, and a considerable amount of glass. The feldspathic microlites are mainly alkaline labradorite, while the phenocrystic crystals are more calcareous, approaching Ab3 An4; but some of the microlites have angles of extinction appropriate to oligoclase. The slide shows decomposition products, especially chlorite, but not in important quantities.	268	Lava			Whole-rock	56.75	0.67	16.89	6.7	0.23	4.24	7.55	3.09	2.24	0.16	100.14	305	NN	3.62	3.44	H2O=0.51	NN																																								305

SAMPLE LOCATION

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