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SAMPLE INFO : 91ABc-1

Sample ID:	91ABc-1
Station ID:	91ABc-1
Latitude:	61.4119
Longitude:	-141.71228
Datum:	NAD83
Date Sampled:	1991-00-00
Sample Type 1:	Tephra Fall
Sample Type 2:	Pumice

Text Description:
Summit pumice; loose accumulation of light-colored pumice, ranging in size from lapilli to blocks as much as 50 cm in diameter. Scattered throughout these tephra deposits, and locally abundant, are angular to subangular clasts of a variety of volcanic rocks, chiefly dark-colored, porphyritic and aphyric andesitic lava, and an occasional block of granitic rock and chlorite-rich amygdaloidal lava. The lithic fragments are similar in size to the pumice fragments and are interpreted to be rock ripped from the vent conduit walls during the explosive eruption(s). Also scattered throughout the tephra are clasts of yellow-orange pumice and lithics that apparently have been hydrothermally altered. Underlying this loose surface layer of pumice and lithic debris is a frozen zone of bedded tephra, consisting of pumice lapilli and blocks and exotic rock fragments disseminated in an ash matrix. White River Ash.

References:

Mount Churchill, Alaska: source of the late Holocene White River Ash

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
91ABc-1	61.4119	-141.71228	Benson, C. S.	1991-00-00	1250 known unit; 187; White River Ash	Churchill, Mt	803--	Summit area of Mount Churchill	Summit pumice; loose accumulation of light-colored pumice, ranging in size from lapilli to blocks as much as 50 cm in diameter. Scattered throughout these tephra deposits, and locally abundant, are angular to subangular clasts of a variety of volcanic rocks, chiefly dark-colored, porphyritic and aphyric andesitic lava, and an occasional block of granitic rock and chlorite-rich amygdaloidal lava. The lithic fragments are similar in size to the pumice fragments and are interpreted to be rock ripped from the vent conduit walls during the explosive eruption(s). Also scattered throughout the tephra are clasts of yellow-orange pumice and lithics that apparently have been hydrothermally altered. Underlying this loose surface layer of pumice and lithic debris is a frozen zone of bedded tephra, consisting of pumice lapilli and blocks and exotic rock fragments disseminated in an ash matrix. White River Ash.	91ABc-1	Tephra Fall	Cumulate		Whole-rock	67.9	0.43	16	2.7	0.06	1.19	3.8	4.25	2.67	0.15	99.13	187	NN	1.27	1.53	H2OP=0.67; H2OM=0.19; CO2=0.01	RAPIDA		70	900	890	< 30	46													26	172	11								< 10			< 10	26	50						187	NN

SAMPLE LOCATION

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