udpated	5/4/05	Todd Bowers	Added wt% units
updated	9/30/04	keith	
updated 	4/29/04	keith	
5/28/04	keith		
georef data		2001-011106	
TI	"The origin of composition gaps at South Sister Volcano, central Oregon; implications for fractional crystallization processes beneath active calc-alkaline volcanoes."		
AU	Brophy-J-G; Dreher-S-T		
AF	"Indiana University, Department of Geological Sciences, Bloomington, IN, United States"		
SO	"Journal of Volcanology and Geothermal Research. 102; 3-4, Pages 287-307. 2000."		
PB	"Elsevier. Amsterdam, Netherlands. 2000."		
CP	Netherlands		
PY	2000		
LA	English		
AB	"South Sister is an active, calc-alkaline strato-volcano located in west-central Oregon in the high Cascades. South Sister contains lavas that range from basalt 50% SiO sub 2  to rhyolite 75% SiO sub 2 . Within this compositional spectrum the lavas are restricted to three distinct populations: basalt/basaltic-andesite, andesite and rhyolite. Compositional, textural and mineralogic criteria indicate that the basaltic-andesites are hybrid mixtures of basalt and andesite magma. This implies that the system is characterized by basalt, andesite and rhyolite magma populations that are separated from one another by composition gaps. Major, minor and trace element modeling suggests that the three magma populations are related to one another primarily through fractional crystallization. We propose a standard fractionation model for generating compositional diversity amongst erupted lavas wherein in situ fractional crystallization occurs within a downward descending solidification front. Extraction and eruption of the interstitial fractionated liquid, now separated from the parental liquid by a composition gap, occurs only after the percentage of crystallization within the solidification front has exceeded the appropriate critical crystallinity value for the given parental magma. We envision a magmatic plumbing system characterized by multiple, independently solidifying bodies of magma. Thus, at any given time, discrete bodies of basalt, andesite and rhyolite magma may exist. Interaction and mixing among these bodies could generate the continuous range of lava compositions that characterize most calc-alkaline volcanic complexes."		
DE	andesites-; basalts-; Bend-Oregon; Cascade-Range; Deschutes-County-Oregon; fractional-crystallization; geochemistry-; igneous-rocks; lava-; magmas-; major-elements; mass-balance; mineral-assemblages; mineral-composition; Oregon-; petrography-; phenocrysts-; processes-; sampling-; South-Sister; trace-elements; United-States; volcanic-rocks; volcanism-; volcanoes-		
CC	"05A-Igneous-and-metamorphic-petrology; 02C-Geochemistry-of-rocks,-soils,-and-sediments"		
DT	Serial																																												
BL	Analytic																																												
MC	LAT| N440000; N440000; LONG: W1211500; W1211500.																																												
IL	Refs 36; illus. incl. 6 tables.																																												
RF	"GeoRef, Copyright 2002, American Geological Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands"																																												
IS	0377-0273																																												
CO	JVGRDQ																																												
AN 	2001-011106																																												
UD	200104																																												
Table Heading																																													
Sample Data																																													
Item	LOCATION	LOCATION COMMENT	SAMPLING TECHNIQUE	LAND/SEA SAMPLING	ROCK_TYPE	ROCK_NAME	SAMPLE COMMENT	GEOLOGICAL_AGE	rock_type	Material	LATITUDE	LONGITUDE	COMMENT	SIO2WT%	TIO2WT%	AL2O3WT%	FEOTWT%	CAOWT%	MGOWT%	MNOWT%	K2OWT%	NA2OWT%	LOIWT%	KWT%	LA	CE	SM	EU	TB	DY	YB	LU	SC	V	CR	CO	RB	SR	CS	BA	HF	TA	TH	U	STATE
Units											DD	DD		wt%	wt%	wt%	wt%	wt%	wt%	wt%	wt%	wt%	wt%	wt%	PPM	PPM	PPM	PPM	PPM	PPM	PPM	PPM	PPM	PPM	PPM	PPM	PPM	PPM	PPM	PPM	PPM	PPM	PPM	PPM	
Method								5			5	5		2	2	2	2	2	2	2	2	2	3	4	1	1	1	1	1	1	1	1	1	1	1	1	1	3	1	3	1	1	1	1	
Sample Name																																													
s_SS-1	CASCADES / HIGH CASCADES / NORTHWESTERN CASCADES / SOUTH SISTER / PACIFIC OCEAN		outcrop	subaerial	volcanic rock	RHYOLITE	LAVA	HOLOCENE	volcanic	whole rock	44.1	-121.75	FUSED SAMPLES	72.07	0.32	14.37	2.33	1.93	0.58	0.05	3.06	4.45	0.8	3.06	21.47	40.8	3.03	0.74	0.38	2.81	2.06	0.27	3.84	21.71	3.6	3.77	66.51	227	2.94	806	4.89	0.85	7.52	2.57	OREGON
s_SS-4	CASCADES / HIGH CASCADES / NORTHWESTERN CASCADES / SOUTH SISTER / PACIFIC OCEAN		outcrop	subaerial	volcanic rock	RHYOLITE	LAVA	HOLOCENE	volcanic	whole rock	44.1	-121.75												3.27	20.77	40.06	2.95	0.73	0.51	3.14	1.47	0.3	3.87	20.73	5.37	4.97	58.42		2.79		5.04	0.75	7.3	2.08	OREGON
s_SS-6	CASCADES / HIGH CASCADES / NORTHWESTERN CASCADES / SOUTH SISTER / PACIFIC OCEAN	MAIN CONE	outcrop	subaerial	volcanic rock	ANDESITE	LAVA	HOLOCENE	volcanic	whole rock	44.1	-121.75													19.01	39.42	5.19	1.41	0.56	5.97	2.58	0.38	14.42	113.72	6.3	12.21	32.93		1.14		4.98	0.71	3.47	1.04	OREGON
s_SS-7	CASCADES / HIGH CASCADES / NORTHWESTERN CASCADES / SOUTH SISTER / PACIFIC OCEAN	MAIN CONE	outcrop	subaerial	volcanic rock	ANDESITE	LAVA	HOLOCENE	volcanic	whole rock	44.1	-121.75													18.33	41.7	4.99	1.43	0.88	4.65	2.41	0.34	14.98	113.21	4.58	12.49	37.05		0.86		5.19	0.67	3.4	1.5	OREGON
s_SS-8	CASCADES / HIGH CASCADES / NORTHWESTERN CASCADES / SOUTH SISTER / PACIFIC OCEAN	MAIN CONE	outcrop	subaerial	volcanic rock	ANDESITE	LAVA	HOLOCENE	volcanic	whole rock	44.1	-121.75													18.26	39.37	4.88	1.54	0.73	5.52	2.7	0.39	15.58	111.61	6.79	12.61	32.61		0.84		5.38	0.61	3.29	1.95	OREGON
s_SS-9	CASCADES / HIGH CASCADES / NORTHWESTERN CASCADES / SOUTH SISTER / PACIFIC OCEAN	MAIN CONE	outcrop	subaerial	volcanic rock	ANDESITE	LAVA	HOLOCENE	volcanic	whole rock	44.1	-121.75	FUSED SAMPLES	63.66	1.03	16.58	6.28	4.26	1.85	0.11	1.91	5	0.11																						OREGON
s_SS-10	CASCADES / HIGH CASCADES / NORTHWESTERN CASCADES / SOUTH SISTER / PACIFIC OCEAN	MAIN CONE	outcrop	subaerial	volcanic rock	ANDESITE	LAVA	HOLOCENE	volcanic	whole rock	44.1	-121.75													18	37.74	4.85	1.5	0.78	4.17	2.45	0.36	14.26	106.29	7.25	13.3	28.86		1.2		4.91	0.63	3.05	1.08	OREGON
s_SS-13	CASCADES / HIGH CASCADES / NORTHWESTERN CASCADES / SOUTH SISTER / PACIFIC OCEAN	MAIN CONE	outcrop	subaerial	volcanic rock	ANDESITE	LAVA	HOLOCENE	volcanic	whole rock	44.1	-121.75	FUSED SAMPLES	62.57	1.05	16.47	6.41	4.47	1.99	0.12	1.84	4.97	0.62	1.84	17.69	40.11	4.82	1.5	0.63	4.56	2.48	0.35	15.13	109.36	5.06	12.75	35.22	400	1.43	566	5.34	0.63	3.49	1.82	OREGON
s_SS-14	CASCADES / HIGH CASCADES / NORTHWESTERN CASCADES / SOUTH SISTER / PACIFIC OCEAN	SUMMIT CONE	outcrop	subaerial	volcanic rock	NOT GIVEN	LAVA	HOLOCENE	volcanic	whole rock	44.1	-121.75													12.52	29.78	4.19	1.47	0.4	4.93	2.18	0.3	20.37	154.92	56.39	23.76	16.71		0.62		3.77	0.44	1.63	1.21	OREGON
s_SS-16	CASCADES / HIGH CASCADES / NORTHWESTERN CASCADES / SOUTH SISTER / PACIFIC OCEAN	MAIN CONE	outcrop	subaerial	volcanic rock	ANDESITE	LAVA	HOLOCENE	volcanic	whole rock	44.1	-121.75													19.38	38.28	5.04	1.46	0.69	4.59	2.45	0.4	14.81	117.92	7.55	12.35	50.46		1.13		5.23	0.58	3.54	1.14	OREGON
s_SS-17	CASCADES / HIGH CASCADES / NORTHWESTERN CASCADES / SOUTH SISTER / PACIFIC OCEAN	MAIN CONE	outcrop	subaerial	volcanic rock	ANDESITE	LAVA	HOLOCENE	volcanic	whole rock	44.1	-121.75	FUSED SAMPLES	63.15	1.07	16.2	6.1	4.09	1.66	0.11	2.03	4.94	0																						OREGON
s_SS-18	CASCADES / HIGH CASCADES / NORTHWESTERN CASCADES / SOUTH SISTER / PACIFIC OCEAN	SUMMIT CONE	outcrop	subaerial	volcanic rock	BASALT	LAVA	HOLOCENE	volcanic	whole rock	44.1	-121.75		50.7	1.37	18.95	9.75	8.16	4.39	0.15	0.44	4.01			10.09	25.68	4.01	1.45	0.43	2.94	2.1	0.27	28.46	232.92	71.08	31.6	20.16		0.57		3.28	0.28	1.36	0.81	OREGON
s_SS-19	CASCADES / HIGH CASCADES / NORTHWESTERN CASCADES / SOUTH SISTER / PACIFIC OCEAN	SUMMIT CONE	outcrop	subaerial	volcanic rock	ANDESITE	LAVA	HOLOCENE	volcanic	whole rock	44.1	-121.75	FUSED SAMPLES	63.5	0.83	15.6	5.32	3.86	1.77	0.09	2.2	4.49	1.96	2.2	20.06	39.52	4.63	1.17	0.63	4.02	2.45	0.35	12.1	95.52	11.1	12.94	40.59	342	1.65	645	5.43	0.66	4.41	1.6	OREGON
s_SS-20	CASCADES / HIGH CASCADES / NORTHWESTERN CASCADES / SOUTH SISTER / PACIFIC OCEAN	SUMMIT CONE	outcrop	subaerial	volcanic rock	ANDESITE	LAVA	HOLOCENE	volcanic	whole rock	44.1	-121.75	FUSED SAMPLES	55.6	1.17	17.83	8.26	7.19	4.14	0.13	1.16	3.99	0.82	1.16	12.3	27.32	4.28	1.36	0.59	5.57	2.01	0.28	20.95	173.15	56.65	26.72	30.87	526	0.57	336	3.31	0.43	1.53	1.44	OREGON
s_SS-21	CASCADES / HIGH CASCADES / NORTHWESTERN CASCADES / SOUTH SISTER / PACIFIC OCEAN	SUMMIT CONE	outcrop	subaerial	volcanic rock	ANDESITE	LAVA	HOLOCENE	volcanic	whole rock	44.1	-121.75	FUSED SAMPLES	55.95	1.19	17.85	8.33	7.19	4.12	0.13	1.03	4.14	0.47	1.03	12.17	26.97	4.08	1.29	0.85	3.89	1.87	0.2	20.81	171.21	58.25	24.96	10.03	530	0.62	347	3.51	0.4	1.29	1.22	OREGON
s_SS-26	CASCADES / HIGH CASCADES / NORTHWESTERN CASCADES / SOUTH SISTER / PACIFIC OCEAN		outcrop	subaerial	volcanic rock	RHYODACITE	LAVA	HOLOCENE	volcanic	whole rock	44.1	-121.75													22.3	43.12	3.08	0.68	0.35	2.44	1.71	0.26	3.22	14.45	1.86	30.31	61.42		2.37		5.94	0.95	6.41	2.79	OREGON
s_SS-30	CASCADES / HIGH CASCADES / NORTHWESTERN CASCADES / SOUTH SISTER / PACIFIC OCEAN	MAIN CONE	outcrop	subaerial	volcanic rock	ANDESITE	LAVA	HOLOCENE	volcanic	whole rock	44.1	-121.75													23.13	46.38	5.29	1.45	0.69	4.11	2.58	0.58	12.05	73.03	3.78	9.99	43.28		1.46		5.77	0.77	4.46	1.54	OREGON
s_SS-31	CASCADES / HIGH CASCADES / NORTHWESTERN CASCADES / SOUTH SISTER / PACIFIC OCEAN	MAIN CONE	outcrop	subaerial	volcanic rock	ANDESITE	LAVA	HOLOCENE	volcanic	whole rock	44.1	-121.75	FUSED SAMPLES	65.4	0.92	16	5.16	3.62	1.35	0.1	2.22	4.79	0.32																						OREGON
s_SS-33	CASCADES / HIGH CASCADES / NORTHWESTERN CASCADES / SOUTH SISTER / PACIFIC OCEAN	MAIN CONE	outcrop	subaerial	volcanic rock	ANDESITE	LAVA	HOLOCENE	volcanic	whole rock	44.1	-121.75													21.95	43.32	4.91	1.41	0.68	4.94	2.38	0.35	11.55	64.94	3.23	9.66	35.39		1.51		5.83	0.65	4.42	1.38	OREGON
s_SS-34	CASCADES / HIGH CASCADES / NORTHWESTERN CASCADES / SOUTH SISTER / PACIFIC OCEAN		outcrop	subaerial	volcanic rock	RHYODACITE	LAVA	HOLOCENE	volcanic	whole rock	44.1	-121.75													20.64	39.28	2.87	0.58	0.3	2.99	1.48	0.27	3.18	9	1.85	4.21	51.85		1.16		5.26	0.89	6.5	2.36	OREGON
s_SS-38	CASCADES / HIGH CASCADES / NORTHWESTERN CASCADES / SOUTH SISTER / PACIFIC OCEAN		outcrop	subaerial	volcanic rock	RHYOLITE	LAVA	HOLOCENE	volcanic	whole rock	44.1	-121.75													20.62	39.3	2.92	0.64	0.53	2.89	1.98	0.28	3.66	21.13	2.24	4.99	69.05		2.65		4.78	0.83	7.01	3.82	OREGON
s_SS-40	CASCADES / HIGH CASCADES / NORTHWESTERN CASCADES / SOUTH SISTER / PACIFIC OCEAN	MAIN CONE	outcrop	subaerial	volcanic rock	ANDESITE	LAVA	HOLOCENE	volcanic	whole rock	44.1	-121.75	FUSED SAMPLES	64	0.97	16.1	5.5	3.77	1.57	0.11	2.07	4.89	0.69	2.07	28.46	49.52	6.21	1.68	0.94	4.23	3.21	0.4	16	87	2	13	40	382	0.81	632	5.92	0.72	4.15	1.26	OREGON
s_SS-45	CASCADES / HIGH CASCADES / NORTHWESTERN CASCADES / SOUTH SISTER / PACIFIC OCEAN	SUMMIT CONE	outcrop	subaerial	volcanic rock	NOT GIVEN	LAVA	HOLOCENE	volcanic	whole rock	44.1	-121.75													14.69	32.17	4.23	1.39	0.64	5.11	2.1	0.28	20.18	153.72	31.67	22.99	27.41		0.85		4.25	0.5	2.51	0.77	OREGON
s_SS-47	CASCADES / HIGH CASCADES / NORTHWESTERN CASCADES / SOUTH SISTER / PACIFIC OCEAN	SUMMIT CONE	outcrop	subaerial	volcanic rock	ANDESITE	LAVA	HOLOCENE	volcanic	whole rock	44.1	-121.75	FUSED SAMPLES	55	1.17	17.8	8.23	7.22	4.14	0.13	0.98	4.07	0.3	0.98	12.72	27.9	4	1.38	0.63	3.56	1.98	0.23	21.13	169.59	59.02	24.2	16.58	530	0.54	341	3.42	0.48	1.36	1.38	OREGON
s_SS-48	CASCADES / HIGH CASCADES / NORTHWESTERN CASCADES / SOUTH SISTER / PACIFIC OCEAN	SUMMIT CONE	outcrop	subaerial	volcanic rock	ANDESITE	LAVA	HOLOCENE	volcanic	whole rock	44.1	-121.75	FUSED SAMPLES	62.5	0.99	16	5.93	4.24	1.8	0.11	1.95	4.53	2.02	1.95	18.01	35.62	4.37	1.23	0.5	4.2	2.42	0.33	12.95	110.73	5.63	10.85	28.64	389	1.33	586	4.75	0.7	3.61	1.22	OREGON
s_SS-49	CASCADES / HIGH CASCADES / NORTHWESTERN CASCADES / SOUTH SISTER / PACIFIC OCEAN	SUMMIT CONE	outcrop	subaerial	volcanic rock	NOT GIVEN	LAVA	HOLOCENE	volcanic	whole rock	44.1	-121.75													19.49	41.13	5.1	1.5	0.66	3.26	2.41	0.4	15.59	129.55	8.23	14.34	30.7		2		5	0.79	3.45	0.89	OREGON
s_SS-52	CASCADES / HIGH CASCADES / NORTHWESTERN CASCADES / SOUTH SISTER / PACIFIC OCEAN		outcrop	subaerial	volcanic rock	RHYODACITE	LAVA	HOLOCENE	volcanic	whole rock	44.1	-121.75													22.47	42.71	2.99	0.65	0.39	2.07	1.75	0.28	3.18	15.36	3	3.3	61.32		2.31		5.86	0.82	6.24	3.26	OREGON
s_SS-60	CASCADES / HIGH CASCADES / NORTHWESTERN CASCADES / SOUTH SISTER / PACIFIC OCEAN		outcrop	subaerial	volcanic rock	RHYOLITE	LAVA	HOLOCENE	volcanic	whole rock	44.1	-121.75													22.21	41.03	3.09	0.69	0.42	2.71	1.75	0.29	3.97	15.32	3.72	4.25	65.78		2.75		5.21	0.82	7.74	3.17	OREGON
s_SS-62	CASCADES / HIGH CASCADES / NORTHWESTERN CASCADES / SOUTH SISTER / PACIFIC OCEAN		outcrop	subaerial	volcanic rock	RHYOLITE	LAVA	HOLOCENE	volcanic	whole rock	44.1	-121.75													22.34	39.39	3.06	0.66	0.46	2.62	1.55	0.26	3.88	20.18	2.78	5.43	77.64		2.66		4.99	0.89	7.49	2.92	OREGON
s_SS-64	CASCADES / HIGH CASCADES / NORTHWESTERN CASCADES / SOUTH SISTER / PACIFIC OCEAN		outcrop	subaerial	volcanic rock	RHYOLITE	LAVA	HOLOCENE	volcanic	whole rock	44.1	-121.75													20.97	39.69	3.1	0.73	0.34	2.69	1.87	0.27	3.87	17.02	2.94	4.14	59.91		2.9		4.92	0.85	7.27	4.29	OREGON
s_SS-66	CASCADES / HIGH CASCADES / NORTHWESTERN CASCADES / SOUTH SISTER / PACIFIC OCEAN		outcrop	subaerial	volcanic rock	RHYODACITE	LAVA	HOLOCENE	volcanic	whole rock	44.1	-121.75													22.41	41.92	2.97	0.7	0.34	2.85	1.86	0.29	3.2	12.72	3.53	6.89	64.78		2.41		5.91	0.92	6.49	2.88	OREGON
s_SS-68	CASCADES / HIGH CASCADES / NORTHWESTERN CASCADES / SOUTH SISTER / PACIFIC OCEAN	MAIN CONE	outcrop	subaerial	volcanic rock	ANDESITE	LAVA	HOLOCENE	volcanic	whole rock	44.1	-121.75													22.44	45.44	5.48	1.57	0.75	6.69	2.43	0.36	6.59	100.99	1.19	12.61	36.87		0.64		5.38	0.66	3.62	1	OREGON
s_SS-69	CASCADES / HIGH CASCADES / NORTHWESTERN CASCADES / SOUTH SISTER / PACIFIC OCEAN	MAIN CONE	outcrop	subaerial	volcanic rock	ANDESITE	LAVA	HOLOCENE	volcanic	whole rock	44.1	-121.75													25.25	45.69	5.71	1.55	0.83	4.64	2.99	0.41	14.94	101.79	2.55	12.86	35.87		0.86		5.7	0.81	4.01	1.73	OREGON
s_SS-70	CASCADES / HIGH CASCADES / NORTHWESTERN CASCADES / SOUTH SISTER / PACIFIC OCEAN	MAIN CONE	outcrop	subaerial	volcanic rock	ANDESITE	LAVA	HOLOCENE	volcanic	whole rock	44.1	-121.75													20.88	45.01	5.15	1.51	0.74	4.11	2.51	0.37	15.12	106.27	3.55	12.13	28.63		0.98		5.58	0.78	3.67	1.74	OREGON
s_SS-73	CASCADES / HIGH CASCADES / NORTHWESTERN CASCADES / SOUTH SISTER / PACIFIC OCEAN	MAIN CONE	outcrop	subaerial	volcanic rock	ANDESITE	LAVA	HOLOCENE	volcanic	whole rock	44.1	-121.75													21.64	46.02	5.36	1.52	0.76	3.95	2.79	0.41	15.03	104.13	3.76	13.19	35.6		1.29		5.13	0.79	3.79	1.61	OREGON
s_SS-75	CASCADES / HIGH CASCADES / NORTHWESTERN CASCADES / SOUTH SISTER / PACIFIC OCEAN		outcrop	subaerial	volcanic rock	RHYODACITE	LAVA	HOLOCENE	volcanic	whole rock	44.1	-121.75													23.18	41.66	3.11	0.62	0.35	2.97	1.7	0.27	3.34	18.88	2.14	4.51	75.7		3.04		4.78	0.9	8.35	3.68	OREGON
s_RM-2	CASCADES / HIGH CASCADES / NORTHWESTERN CASCADES / SOUTH SISTER / PACIFIC OCEAN		outcrop	subaerial	volcanic rock	RHYOLITE	LAVA	HOLOCENE	volcanic	whole rock	44.1	-121.75	FUSED SAMPLES	73.73	0.28	13.95	2.06	1.75	0.5	0.05	3.24	4.22	0.61	3.24	21.32	41.91	2.96	0.94	0.34	1.68	1.41	0.3	3.43	18.46	3.55	4.62	77.64	194	3.36	832	5.21	0.96	8.42	3.36	OREGON
s_RM-3	CASCADES / HIGH CASCADES / NORTHWESTERN CASCADES / SOUTH SISTER / PACIFIC OCEAN		outcrop	subaerial	volcanic rock	RHYOLITE	LAVA	HOLOCENE	volcanic	whole rock	44.1	-121.75													22.07	42.78	3.04	0.65	0.35	1.53	2.11	0.29	3.46	15.83	2.98	3.58	80.05		3.05		5.12	0.88	8.36	2.94	OREGON
s_RM-4	CASCADES / HIGH CASCADES / NORTHWESTERN CASCADES / SOUTH SISTER / PACIFIC OCEAN		outcrop	subaerial	volcanic rock	RHYOLITE	LAVA	HOLOCENE	volcanic	whole rock	44.1	-121.75	FUSED SAMPLES	72.38	0.27	14.05	2	1.71	0.5	0.05	3.27	4.24	1.11		22.06	40.45	2.92	0.62	0.47	2.19	1.57	0.29	3.47	22.02	2.85	4.01	76.94		3.07		5.03	0.92	8.28	3.4	OREGON
Method Data																																													
1	INAA	372																																											
2	EMP EPMA	416																																											
3	IGN	416																																											
4	ICPAES	416																																											
5	NN	480