Table S1
Sample1	2727M01	2727M08	2728M01	2728M04a	2729M06	2729M08	2730M01b	2731M01	2731M07		0719P05b	1724M01	2714M02	1728M05a		1721M01 
Location2	AP	AP	AP	AP	AP	AP	AP	AP	AP		CM	CM	CM	CM		TM 
																 
quartz	27.5	26.2	17.1	12.5	32.3	17.6	20.9	35.6	0		43.4	35.3	25.2	34.6		19.7 
feldspar3	58.5	66.2	55.4	61.5	55.6	64.4	49.5	60.3	63.4		49.2	49.7	57.9	58		52.7 
amphibole	5	1.5	12.4	21.6	5.8	15.1	25	0	31.9		1.1	13.9	12.4	1		15.3 
biotite	8	4.6	13	3.8	4.2	0.5	3.1	0	2.6		5.3	0	3.5	5.9		9.4 
muscovite	0	0	0	0	0	0	0	4.1	0		0	0	0	0		0 
oxide	1	1.5	2.1	0.5	2.1	2.4	1.5	0	2.1		1.1	1.1	1	0.5		3 
																 
% An4	36	29.4	38	54	38	38	56	23	86		30.2	34	40	33.2		38 
																 
1 Modal mineralogy (%) based on thin section point counts (n = 200).												
				 
2 Sample locations: APÑAlaska Peninsula; CMÑChugach Mountains; TMÑTalkeetna Mountains.										
						 
3 Samples contain ²5 % k-feldspar.															
	 
"4 Average plagioclase compositions. Plain text numbers were measure by electron microprobe (Johnsen, 2007; Rioux, unpublished). Italic numbers are estimated based on compositional trends from 
other Talkeetna arc plutonic rocks (Greene et al., 2006; Hacker et al., 2008). "