Table A1. Isotopic analyses of dated 40Ar/39Ar samples
Hornblende data
Sample: MD41 Hornblende	J=0.0002360
T	t	40(mol)	40/39	37/39	36/39	K/Ca	∑ 39Ar	40Ar*	Age ± 1s Ma	
700	8	 2.0e-14	599.8123	1.4939	1.7015	0.33	0.01072	0.162	40.8 ± 0.9	
750	8	 5.8e-15	244.1957	1.1064	0.6905	0.44	0.01816	0.164	17.0 ± 0.7	
850	8	 9.0e-15	152.1310	3.7023	0.3298	0.13	0.03805	0.359	23.1 ± 0.3	
925	8	 4.6e-14	445.0830	9.4053	1.0969	0.052	0.07774	0.272	50.8 ± 0.6	
950	8	 3.3e-14	241.3900	13.6239	0.4284	0.036	0.13563	0.476	48.2 ± 0.5	
975	8	 1.6e-13	151.6020	13.1128	0.0801	0.037	0.58795	0.844	53.7 ± 0.5	
990	8	 1.5e-14	147.5853	11.8081	0.0348	0.041	0.63055	0.930	57.5 ± 0.6	
1000	8	 1.5e-15	109.3486	8.2883	0.0826	0.059	0.63577	0.777	35.8 ± 0.6	
1010	8	 1.3e-15	121.9671	10.0518	0.0775	0.049	0.64006	0.812	41.7 ± 0.6	
1040	8	 9.1e-15	140.9104	12.8987	0.0871	0.038	0.66717	0.817	48.4 ± 0.5	
1070	8	 1.2e-14	149.6768	14.0075	0.0948	0.035	0.70041	0.813	51.1 ± 0.5	
1100	8	 4.0e-14	161.3818	15.1877	0.1083	0.032	0.80809	0.802	54.3 ± 0.6	
1150	8	 6.6e-14	155.7274	13.6054	0.0524	0.036	0.98834	0.901	58.7 ± 0.6	
1175	8	 3.2e-15	155.4269	12.9422	0.0339	0.038	0.99696	0.936	60.9 ± 0.7	
1200	8	 1.3e-15	174.6902	13.0313	0.0701	0.038	1.00000	0.881	64.4 ± 0.9	
Total fusion age = 53.09 ± 0.53 Ma

Sample: MD49B Hornblende	J=0.0009285
T	t	40(mol)	40/39	37/39	36/39	K/Ca	∑ 39Ar	40Ar*	Age ± 1s Ma	
700	8	 1.5e-15	34.0420	0.2563	0.0540	1.9	0.08078	0.531	30.0 ± 1.3	
800	8	 1.4e-15	49.5940	0.8404	0.0495	0.58	0.13596	0.705	57.6 ± 1.5	
900	8	 5.8e-16	71.3302	7.7358	0.0858	0.063	0.15450	0.645	75.4 ± 3.1	
950	8	 2.4e-16	50.1900	11.6741	0.0985	0.042	0.16640	0.420	34.9 ± 3.7	
1000	8	 2.1e-16	41.9011	13.1406	0.0933	0.037	0.17933	0.342	23.9 ± 3.4	
1020	8	 1.3e-16	36.0728	14.6747	0.0538	0.033	0.18898	0.560	33.5 ± 4.4	
1040	8	 1.4e-16	43.7088	17.8204	0.0741	0.027	0.19816	0.499	36.2 ± 4.6	
1060	8	 1.3e-16	35.3420	17.2097	0.0511	0.028	0.20871	0.573	33.6 ± 4.0	
1080	8	 1.7e-16	36.1071	20.4224	0.0657	0.024	0.22235	0.462	27.7 ± 3.1	
1100	8	 1.4e-15	34.0039	23.3213	0.0190	0.021	0.34722	0.834	46.9 ± 0.7	
1125	8	 5.6e-15	38.6054	20.5922	0.0093	0.024	0.77743	0.929	59.1 ± 0.5	
1150	8	 2.2e-16	37.0307	14.5688	0.0615	0.034	0.79346	0.509	31.3 ± 2.7	
1175	8	 3.8e-16	35.8055	23.5522	0.0334	0.021	0.82718	0.724	42.9 ± 1.3	
1200	8	 1.1e-15	42.4794	32.6348	0.0292	0.015	0.91926	0.797	55.8 ± 0.8	
1225	8	 8.7e-16	42.3169	28.4343	0.0205	0.017	0.98958	0.857	59.7 ± 0.8	
1375	5	 4.5e-16	193.2442	47.0319	0.1762	0.010	1.00000	0.731	222.2 ± 6.4	
Total fusion age = 54.12 ± 0.53 Ma. 

Muscovite data
Sample: MD31B Muscovite	J=0.0009841
T	t	40(mol)	40/39	37/39	36/39	K/Ca	∑ 39Ar	40Ar*	Age ± 1s Ma	
900	8	 5.4e-15	23.3345	0.1880	0.0548	2.6	0.06530	0.306	12.6 ± 0.4	
950	8	 8.3e-15	7.4952	0.0226	0.0006	22	0.37252	0.978	13.0 ± 0.1	
975	8	 4.1e-15	7.2128	0.0166	0.0000	30	0.52915	0.998	12.7 ± 0.1	
1000	8	 2.5e-15	7.1994	0.0352	0.0003	14	0.62673	0.987	12.6 ± 0.2	
1050	8	 2.1e-15	7.2738	0.0548	0.0001	8.9	0.70798	0.997	12.8 ± 0.1	
1100	8	 1.7e-15	7.4469	0.0391	0.0012	13	0.77020	0.951	12.5 ± 0.2	
1200	8	 4.7e-15	7.4993	0.0607	0.0007	8.1	0.94329	0.974	12.9 ± 0.2	
1300	8	 1.6e-15	7.7756	0.1906	0.0006	2.6	1.00000	0.976	13.4 ± 0.2	
Total fusion age = 12.85 ± 0.12 Ma
Weighted mean age = 12.79 ± 0.12 Ma
Inverse isochron age =12.85 ± 0.13 Ma (MSWD = 1.59; 40Ar/36Ar =293.6 ± 4.3)
Steps used: 900-1200 or 94% ∑ 39Ar

Sample: MD47 Muscovite		J=0.0010044
T	t	40(mol)	40/39	37/39	36/39	K/Ca	∑ 39Ar	40Ar*	Age ± 1s Ma	
900	12	 2.6e-15	43.5133	0.0047	0.1082	105	0.03083	0.265	20.6 ± 0.9	
950	12	 2.4e-15	19.3045	0.0012	0.0287	423	0.09285	0.561	19.5 ± 0.4	
1000	12	 9.1e-15	9.7830	0.0002	0.0013	3212	0.56426	0.962	17.0 ± 0.2	
1066	12	 4.7e-15	9.6375	0.0003	0.0007	1677	0.81054	0.980	17.0 ± 0.2	
1133	12	 1.4e-15	10.7914	0.0011	0.0024	434	0.87429	0.935	18.2 ± 0.3	
1166	12	 7.6e-16	10.8827	0.0020	0.0030	241	0.90971	0.919	18.0 ± 0.4	
1200	12	 7.7e-16	9.1587	0.0017	0.0008	292	0.95266	0.974	16.1 ± 0.3	
1250	12	 5.6e-16	8.9410	0.0023	0.0002	218	0.98471	0.994	16.0 ± 0.4	
1300	12	 2.9e-16	9.7116	0.0047	0.0008	104	1.00000	0.977	17.1 ± 0.8	
Total fusion age = 17.30 ± 0.16 Ma
Weighted mean age = 16.99 ± 0.15 Ma
Inverse isochron age =17.09 ± 0.19 Ma. (MSWD = 0.02; 40Ar/36Ar=242.3 ± 8.2)
Steps used: 1000, 1066 or 73% ∑ 39Ar

Sample: MD49A Muscovite	J=0.0009784
T	t	40(mol)	40/39	37/39	36/39	K/Ca	∑ 39Ar	40Ar*	Age ± 1s Ma	
800	12	7.00E-16	34.0528	0.0532	0.086	9.2	0.00617	0.254	15.2 ± 1.8	
900	12	1.10E-15	19.3665	0.0281	0.0341	17	0.02252	0.479	16.3 ± 0.5	
950	12	1.80E-15	17.7476	0.0066	0.0287	74	0.05221	0.521	16.3 ± 0.4	
1000	12	1.30E-14	10.0574	0.0022	0.0044	219	0.43435	0.872	15.4 ± 0.2	
1050	12	8.90E-15	8.9096	0.0037	0.0006	131	0.73322	0.98	15.3 ± 0.1	
1075	12	2.00E-15	9.2475	0.008	0.0016	61	0.7989	0.95	15.4 ± 0.2	
1100	12	1.00E-15	9.7129	0.0171	0.0027	29	0.82979	0.919	15.7 ± 0.3	
1133	12	1.00E-15	10.0839	0.0212	0.0024	23	0.86088	0.929	16.5 ± 0.3	
1166	12	1.20E-15	10.1128	0.0054	0.0023	91	0.8975	0.934	16.6 ± 0.2	
1200	12	1.40E-15	9.0786	0.0147	0.0014	33	0.94227	0.955	15.2 ± 0.2	
1250	12	9.40E-16	8.9043	0.021	0.0007	23	0.97378	0.978	15.3 ± 0.3	
1300	12	8.50E-16	9.6932	0.0606	0.0024	8.1	1	0.928	15.8 ± 0.3	
Total fusion age = 15.52 ± 0.14 Ma
Weighted mean plateau age = 15.37 ± 0.14 Ma
Inverse isochron age =15.34 ± 0.14 Ma. (MSWD = 0.85; 440Ar/36Ar=307.1 ± 10.3)
Steps used: 1000-1100 or 78% ∑ 39Ar

Sample: MD79 Muscovite		J=0.0009855
T	t	40(mol)	40/39	37/39	36/39	K/Ca	∑ 39Ar	40Ar*	Age ± 1s Ma	
800	12	7.20E-16	12.0109	0.0043	0.0069	113	0.01778	0.831	17.7 ± 0.4	
900	12	4.20E-16	9.1015	0.0057	0.0005	86	0.03138	0.984	15.9 ± 0.5	
950	12	1.90E-15	9.4483	0.0013	0.0001	379	0.09107	0.996	16.7 ± 0.2	
1000	12	6.20E-15	9.6749	0.0016	0.0007	298	0.27846	0.979	16.8 ± 0.2	
1050	12	6.70E-15	9.9794	0.0035	0.0015	140	0.47679	0.955	16.9 ± 0.2	
1075	12	2.80E-15	10.4174	0.007	0.0033	70	0.55457	0.906	16.7 ± 0.2	
1100	12	2.30E-15	10.4273	0.0048	0.0034	101	0.61844	0.904	16.7 ± 0.2	
1133	12	2.30E-15	10.3747	0.0083	0.0042	59	0.6836	0.882	16.2 ± 0.2	
1166	12	2.80E-15	10.1586	0.0067	0.0041	74	0.76491	0.881	15.8 ± 0.2	
1200	12	3.20E-15	9.3844	0.0062	0.0028	79	0.86466	0.912	15.2 ± 0.2	
1250	12	2.60E-15	9.0284	0.0119	0.0011	41	0.94948	0.963	15.4 ± 0.2	
1300	12	1.60E-15	9.0865	0.0200	0.0005	25	1	0.983	15.8 ± 0.2	
Total fusion age = 16.33 ± 0.15 Ma
Weighted mean plateau age = 16.77 ± 0.15 Ma
Inverse isochron age =16.79 ± 0.16 Ma (MSWD =1.23; 40Ar/36Ar=290.1 ± 21.1)
Steps used: 950-1100 or 59% ∑ 39Ar

Sample: MD93 Muscovite	J=0.0009825
T	t	40(mol)	40/39	37/39	36/39	K/Ca	∑ 39Ar	40Ar*	Age ± 1s Ma	
800	12	1.80E-15	16.1532	0.0677	0.0296	7.2	0.00809	0.459	13.1 ± 0.4	
900	12	3.20E-15	12.0739	0.0660	0.0125	7.4	0.02706	0.694	14.8 ± 0.2	
950	12	8.00E-15	12.465	0.0453	0.0131	11	0.07283	0.69	15.2 ± 0.2	
1000	12	4.80E-14	9.1336	0.0099	0.0013	49	0.44903	0.957	15.4 ± 0.2	
1050	12	2.60E-14	8.7766	0.0213	0.0012	23	0.66301	0.959	14.9 ± 0.2	
1075	12	7.70E-15	9.3385	0.0883	0.0038	5.5	0.72211	0.881	14.5 ± 0.2	
1100	12	4.60E-15	9.9663	0.0703	0.0066	7	0.75531	0.803	14.1 ± 0.2	
1133	12	5.50E-15	9.7199	0.0564	0.006	8.7	0.79534	0.816	14.0 ± 0.2	
1166	12	1.00E-14	9.045	0.0381	0.003	13	0.87578	0.901	14.4 ± 0.2	
1200	12	1.20E-14	9.2421	0.0527	0.003	9.3	0.9649	0.905	14.8 ± 0.2	
1250	12	4.30E-15	11.8638	0.2470	0.0102	2	0.99116	0.747	15.6 ± 0.2	
1300	12	1.60E-15	13.4106	0.4964	0.0189	0.99	1	0.585	13.8 ± 0.5	
Total fusion age = 14.96 ± 0.14 Ma
Weighted mean age = 15.29 ± 0.15 Ma
Inverse isochron age =15.45 ± 0.18 Ma (MSWD =0.00; 40Ar/36Ar=283.5 ± 0.0)
Steps used: 950, 1000 or 42% ∑ 39Ar

Sample: MD100 Muscovite	J=0.0009986
T	t	40(mol)	40/39	37/39	36/39	K/Ca	∑ 39Ar	40Ar*	Age ± 1s Ma	
800	12	6.90E-17	15.5563	0.0703	0.0052	7	0.00071	0.902	25.1 ± 5.5	
900	12	1.10E-15	27.7901	0.0160	0.0614	31	0.00698	0.348	17.3 ± 1.0	
950	12	6.30E-15	29.4567	0.0015	0.0614	333	0.04111	0.384	20.2 ± 0.4	
1000	12	3.10E-14	10.1705	0.0006	0.0036	793	0.52821	0.894	16.3 ± 0.1	
1050	12	1.30E-14	9.3325	0.0016	0.001	315	0.75454	0.969	16.2 ± 0.2	
1075	12	2.80E-15	9.914	0.0022	0.002	218	0.79922	0.941	16.7 ± 0.2	
1100	12	1.80E-15	10.1852	0.0017	0.0028	282	0.82813	0.918	16.8 ± 0.2	
1133	12	1.70E-15	10.1625	0.0000	0.0026	<0.001	0.85476	0.923	16.8 ± 0.2	
1166	12	1.60E-15	10.1431	0.0019	0.0034	252	0.88069	0.9	16.4 ± 0.2	
1200	12	2.80E-15	9.3388	0.0010	0.0014	468	0.92885	0.956	16.0 ± 0.	
1250	12	2.90E-15	8.9851	0.0010	0.0006	505	0.98085	0.981	15.8 ± 0.2	
1300	12	1.10E-15	9.0778	0.0026	0.0004	186	1	0.987	16.1 ± 0.3	
Total fusion age = 16.44 ± 0.15 Ma
Weighted mean age = 16.27 ± 0.15 Ma
Inverse isochron age =16.18 ± 0.16 Ma (MSWD =0.17; 40Ar/36Ar=316.3 ± 5.7)
Steps used: 1000, 1050, 1166 or 74% ∑ 39Ar

Sample: MD48A Muscovite	J=0.0002349
T	t	40(mol)	40/39	37/39	36/39	K/Ca	∑ 39Ar	40Ar*	Age ± 1s Ma	
650	8	 2.3e-14	247.3667	0.0288	0.7397	17	0.02057	0.116	12.2 ± 0.3	
700	8	 3.3e-14	174.5212	0.0140	0.4846	35	0.06310	0.180	13.2 ± 0.2	
750	8	 6.2e-14	45.7204	0.0027	0.0421	183	0.36601	0.728	14.0 ± 0.1	
800	8	 4.2e-14	35.2428	0.0032	0.0070	152	0.63405	0.941	14.0 ± 0.1	
900	8	 3.0e-14	37.9258	0.0037	0.0159	133	0.81068	0.876	14.0 ± 0.1	
1050	8	 2.5e-14	42.7462	0.0061	0.0318	80	0.94316	0.780	14.1 ± 0.1	
1200	8	 8.9e-15	35.0079	0.0143	0.0058	34	1.00000	0.951	14.1 ± 0.1	
Total fusion age = 13.96 ± 0.14 Ma
Weighted mean plateau age = 14.03 ± 0.14 Ma
Inverse isochron age =14.01 ± 0.14 Ma (MSWD =1.63; 40Ar/36Ar=298.2 ± 1.8)
Steps used: 750, 800, 900, 1050, 1200 or 94% ∑ 39Ar

Sample: MD55 Muscovite		J=0.0002344
T	t	40(mol)	40/39	37/39	36/39	K/Ca	∑ 39Ar	40Ar*	Age ± 1s Ma	
600	8	 7.2e-14	50.0620	0.0037	0.0546	133	0.30381	0.677	14.3 ± 0.1	
650	8	 6.2e-14	37.6494	0.0029	0.0118	170	0.65074	0.908	14.4 ± 0.1	
700	8	 1.9e-14	37.8286	0.0011	0.0100	433	0.75583	0.922	14.7 ± 0.1	
800	8	 1.5e-14	39.9662	0.0018	0.0177	278	0.83309	0.869	14.6 ± 0.1	
950	8	 2.5e-14	37.9668	0.0010	0.0095	503	0.97277	0.926	14.8 ± 0.1	
1050	8	 3.7e-15	37.8215	0.0016	0.0131	297	0.99343	0.898	14.3 ± 0.2	
1200	8	 1.4e-15	46.0224	0.0052	0.0375	94	1.00000	0.759	14.7 ± 0.3	
Total fusion age = 14.47 ± 0.13 Ma
Weighted mean age = 14.38 ± 0.12 Ma
Inverse isochron age =14.78 ± 0.13 Ma (MSWD =0.58; 40Ar/36Ar=274.8 ± 3.1)
Steps used: 600, 650 or 65% ∑ 39Ar

Sample: MD64A Muscovite	J=0.0002412
T	t	40(mol)	40/39	37/39	36/39	K/Ca	∑ 39Ar	40Ar*	Age ± 1s Ma	
525	8	 1.2e-14	154.4846	0.0090	0.4315	54	0.01194	0.175	11.7 ± 0.3	
550	8	 8.1e-15	119.2983	0.0060	0.3019	82	0.02200	0.252	13.0 ± 0.2	
600	8	 2.8e-14	86.2338	0.0028	0.1848	175	0.06928	0.367	13.7 ± 0.2	
700	8	 1.3e-13	36.7557	0.0014	0.0178	348	0.57280	0.857	13.6 ± 0.1	
800	8	 6.6e-14	34.9330	0.0018	0.0113	270	0.85113	0.904	13.7 ± 0.1	
950	8	 3.0e-14	36.5121	0.0040	0.0164	122	0.97075	0.867	13.7 ± 0.1	
1100	8	 6.7e-15	33.9536	0.0111	0.0050	44	1.00000	0.957	14.1 ± 0.1	
Total fusion age = 13.66 ± 0.12 Ma
Weighted mean plateau age = 13.69 ± 0.12 Ma
Inverse isochron age =13.68 ± 0.13 Ma (MSWD =3.01; 40Ar/36Ar=295.6 ± 1.6)
Steps used: 600, 700, 800 or 83% ∑ 39Ar

Sample: MD69B Muscovite	J=0.0002443
T	t	40(mol)	40/39	37/39	36/39	K/Ca	∑ 39Ar	40Ar*	Age ± 1s Ma	
600	8	 1.1e-13	70.9476	0.0024	0.1408	204	0.28407	0.413	12.9 ± 0.1	
633	8	 4.2e-14	37.3298	0.0020	0.0240	251	0.49102	0.810	13.3 ± 0.1	
666	8	 2.9e-14	34.6022	0.0000	0.0145	<0.001	0.64412	0.876	13.3 ± 0.1	
700	8	 1.9e-14	36.3789	0.0000	0.0201	<0.001	0.73920	0.836	13.4 ± 0.1	
750	8	 1.4e-14	39.9521	0.0000	0.0322	<0.001	0.80413	0.762	13.4 ± 0.1	
800	8	 1.2e-14	42.6476	0.0000	0.0427	<0.001	0.85377	0.704	13.2 ± 0.1	
900	8	 1.9e-14	38.2443	0.0000	0.0244	<0.001	0.94581	0.812	13.6 ± 0.1	
1000	8	 6.8e-15	33.8805	0.0000	0.0089	<0.001	0.98258	0.922	13.7 ± 0.1	
1100	8	 3.6e-15	38.2633	0.1700	0.0235	2.9	1.00000	0.818	13.7 ± 0.1	
Total fusion age = 13.24 ± 0.06 Ma
Weighted mean plateau age = 13.33 ± 0.06 Ma
Inverse isochron age =13.29 ± 0.09 Ma (MSWD =1.52; 40Ar/36Ar=300.4 ± 7.4)
Steps used: 633, 666, 700, 750 or 52% ∑ 39Ar

Sample: MD71 Muscovite		J=0.0009956
T	t	40(mol)	40/39	37/39	36/39	K/Ca	∑ 39Ar	40Ar*	Age ± 1s Ma	
900	12	 5.9e-17	5.2320	0.0242	0.0020	20	0.00433	0.885	8.3 ± 2.2	
950	12	 3.9e-16	7.8729	0.0055	0.0005	89	0.02336	0.983	13.8 ± 0.5	
1000	12	 1.9e-15	8.3262	0.0012	0.0025	401	0.10913	0.912	13.6 ± 0.2	
1050	12	 3.3e-15	8.9381	0.0007	0.0044	674	0.25322	0.856	13.7 ± 0.2	
1075	12	 1.9e-15	10.5071	0.0015	0.0101	325	0.32280	0.717	13.5 ± 0.2	
1100	12	 1.7e-15	11.8854	0.0019	0.0138	264	0.37944	0.658	14.0 ± 0.3	
1133	12	 2.2e-15	11.3332	0.0014	0.0125	353	0.45508	0.673	13.7 ± 0.2	
1166	12	 4.5e-15	9.7204	0.0006	0.0074	838	0.63474	0.777	13.5 ± 0.1	
1200	12	 3.3e-15	8.1843	0.0007	0.0023	728	0.79100	0.916	13.4 ± 0.1	
1250	12	 2.0e-15	7.7814	0.0010	0.0006	468	0.89149	0.977	13.6 ± 0.2	
1300	12	 2.2e-15	7.6442	0.0010	0.0004	505	1.00000	0.984	13.5 ± 0.1	
Total fusion age = 13.55 ± 0.13 Ma
Weighted mean plateau age = 13.48 ± 0.12 Ma
Inverse isochron age =13.48 ± 0.13 Ma (MSWD =0.97; 40Ar/36Ar=299.9 ± 7.1)
Steps used: 1100-1300 or 62% ∑ 39Ar

Sample: MD86 Muscovite		J=0.0002465
T	t	40(mol)	40/39	37/39	36/39	K/Ca	∑ 39Ar	40Ar*	Age ± 1s Ma	
575	8	 4.9e-14	84.2076	0.0057	0.1898	86	0.03977	0.334	12.5 ± 0.1	
600	8	 1.0e-13	36.3677	0.0015	0.0233	317	0.23451	0.811	13.1 ± 0.1	
625	8	 1.0e-13	31.2517	0.0014	0.0055	353	0.45468	0.948	13.1 ± 0.1	
650	8	 6.6e-14	30.7353	0.0016	0.0037	303	0.60077	0.965	13.1 ± 0.1	
700	8	 6.4e-14	30.9628	0.0017	0.0045	284	0.74065	0.957	13.1 ± 0.1	
800	8	 5.2e-14	32.4447	0.0016	0.0095	303	0.84937	0.914	13.1 ± 0.1	
900	8	 4.3e-14	33.1849	0.0026	0.0123	189	0.93676	0.890	13.1 ± 0.1	
1050	8	 2.9e-14	31.6938	0.0035	0.0074	140	1.00000	0.931	13.1 ± 0.1	
Total fusion age = 13.09 ± 0.05 Ma
Weighted mean plateau age = 13.14 ± 0.05 Ma
Inverse isochron age =13.13 ± 0.06 Ma (MSWD =0.15; 40Ar/36Ar=296.0 ± 2.2)
Steps used: 625, 650, 700, 800 or 61% ∑ 39Ar

Sample: MD97 Muscovite		J=0.0002484
T	t	40(mol)	40/39	37/39	36/39	K/Ca	∑ 39Ar	40Ar*	Age± 1s Ma	
650	8	 2.7e-13	36.8374	0.0007	0.0225	693	0.53025	0.820	13.5 ± 0.1	
675	8	 7.1e-14	31.8900	0.0019	0.0053	262	0.68941	0.951	13.5 ± 0.1	
700	8	 2.8e-14	32.9276	0.0027	0.0086	183	0.74901	0.923	13.6 ± 0.1	
750	8	 1.9e-14	34.9549	0.0037	0.0155	132	0.78774	0.869	13.6 ± 0.1	
850	8	 3.1e-14	36.1403	0.0023	0.0197	216	0.84916	0.839	13.5 ± 0.1	
950	8	 4.3e-14	36.3596	0.0022	0.0205	225	0.93422	0.834	13.5 ± 0.1	
1050	8	 1.6e-14	32.2471	0.0035	0.0065	141	0.96972	0.940	13.5 ± 0.1	
1200	8	 1.4e-14	31.8632	0.0027	0.0040	180	1.00000	0.963	13.7 ± 0.1	
Total fusion age = 13.51 ± 0.06 Ma
Weighted mean age = 13.54 ± 0.05 Ma
Inverse isochron age =13.54 ± 0.06 Ma (MSWD =0.71; 40Ar/36Ar=295.2 ± 1.6)
Steps used: 675, 700, 750, 850, 950, 1050 or 44% ∑ 39Ar

Sample: MD52 Muscovite		J=0.0002391
T	t	40(mol)	40/39	37/39	36/39	K/Ca	∑ 39Ar	40Ar*	Age ± 1s Ma	
600	8	 6.7e-15	40.8473	0.1247	0.1193	3.9	0.01121	0.137	2.4 ± 0.7	
650	8	 5.1e-15	82.4969	0.0453	0.2049	11	0.01544	0.266	9.4 ± 0.7	
700	8	 1.7e-14	140.4038	0.0152	0.3867	32	0.02356	0.186	11.2 ± 0.4	
750	8	 1.2e-13	45.4516	0.0509	0.0723	9.6	0.19779	0.530	10.4 ± 0.3	
775	8	 1.3e-13	35.6669	0.0494	0.0378	9.9	0.44155	0.687	10.5 ± 0.2	
800	8	 1.0e-13	36.5844	0.0467	0.0345	10	0.63643	0.721	11.3 ± 0.2	
825	8	 7.4e-14	41.2940	0.0550	0.0348	8.9	0.75892	0.751	13.3 ± 0.2	
875	8	 5.3e-14	35.8692	0.0273	0.0179	18	0.85996	0.853	13.1 ± 0.1	
950	8	 3.6e-14	36.4715	0.0238	0.0192	21	0.92663	0.845	13.2 ± 0.1	
1050	8	 2.7e-14	37.5995	0.0253	0.0225	19	0.97587	0.823	13.3 ± 0.1	
1200	8	 1.4e-14	39.3819	0.0292	0.0306	17	1.00000	0.770	13.0 ± 0.1	
Total fusion age = 11.56 ± 0.13 Ma
Weighted mean plateau age = 13.39 ± 0.12 Ma
Inverse isochron age =13.44 ± 0.22 Ma (MSWD =0.18; 40Ar/36Ar=289.3 ± 3.6)
Steps used: 825, 875, 950, 1050 97% ∑ 39Ar

Biotite data
Sample: MD37 Biotite	J=0.0009893
T	t	40(mol)	40/39	37/39	36/39	K/Ca	∑ 39Ar	40Ar*	Age ± 1s Ma	
800	12	 8.4e-16	29.0910	0.0000	0.0777	0	0.00373	0.211	10.9 ± 1.0	
850	12	 2.3e-15	14.6854	0.0204	0.0252	24	0.02370	0.494	12.9 ± 0.3	
900	12	 5.0e-15	9.6434	0.0100	0.0075	49	0.09048	0.770	13.2 ± 0.1	
950	12	 8.6e-15	8.1975	0.0064	0.0021	77	0.22746	0.923	13.5 ± 0.1	
1000	12	 1.1e-14	8.6642	0.0070	0.0033	70	0.39386	0.889	13.7 ± 0.1	
1050	12	 1.2e-14	7.9288	0.0113	0.0011	43	0.58252	0.959	13.5 ± 0.1	
1100	12	 8.8e-15	8.0702	0.0376	0.0017	13	0.72413	0.937	13.4 ± 0.1	
1150	12	 1.0e-15	8.7553	0.0125	0.0043	39	0.73951	0.856	13.3 ± 0.3	
1200	12	 1.2e-14	7.8808	0.0082	0.0010	60	0.93820	0.963	13.5 ± 0.1	
1300	12	 4.0e-15	8.3502	0.0838	0.0022	5.9	1.00000	0.923	13.7 ± 0.2	
Total fusion age = 13.49 ± 0.15 Ma
Weighted mean plateau age = 13.49 ± 0.12 Ma
Inverse isochron age =13.58 ± 0.13 Ma (MSWD =0.35; 40Ar/36Ar=253.4 ± 16.4)
Steps used: 1050, 1100, 1150, 1200 or 54% ∑ 39Ar

Sample: MD33 Biotite	J=0.0010118
T	t	40(mol)	40/39	37/39	36/39	K/Ca	∑ 39Ar	40Ar*	Age ± 1s Ma	
700	12	 4.3e-15	97.9842	0.0353	0.2663	14	0.00413	0.197	34.9 ± 1.5	
800	12	 6.3e-15	53.7193	0.0066	0.1539	75	0.01526	0.154	15.0 ± 0.8	
850	12	 9.5e-15	26.2582	0.0021	0.0603	230	0.04956	0.321	15.3 ± 0.3	
900	12	 1.1e-14	12.9807	0.0015	0.0150	325	0.13039	0.659	15.6 ± 0.2	
950	12	 1.7e-14	9.9230	0.0012	0.0047	398	0.28862	0.860	15.5 ± 0.1	
1000	12	 1.3e-14	9.3345	0.0019	0.0026	256	0.41598	0.918	15.6 ± 0.1	
1050	12	 7.1e-15	9.4102	0.0014	0.0030	362	0.48808	0.907	15.5 ± 0.1	
1100	12	 1.0e-14	9.4914	0.0016	0.0034	301	0.59316	0.894	15.4 ± 0.1	
1150	12	 2.5e-14	9.4359	0.0008	0.0031	643	0.84953	0.904	15.5 ± 0.1	
1200	12	 1.0e-14	10.2345	0.0037	0.0049	133	0.94256	0.859	16.0 ± 0.2	
1300	12	 7.6e-15	12.6229	0.0217	0.0024	23	1.00000	0.945	21.6 ± 0.2	
Total fusion age = 15.97 ± 0.14 Ma
Weighted mean age = 15.51 ± 0.14 Ma
Inverse isochron age =15.52 ± 0.14 Ma (MSWD =1.08; 40Ar/36Ar=294.1 ± 1.5)
Steps used: 800-1150 or 85% ∑ 39Ar

Sample: MD39 Biotite	J=0.0010072
T	t	40(mol)	40/39	37/39	36/39	K/Ca	∑ 39Ar	40Ar*	Age ± 1s Ma	
800	12	 2.9e-16	12.5906	0.0133	0.0030	37	0.00293	0.929	21.1 ± 1.1	
850	12	 8.5e-17	12.2466	0.0441	0.0033	11	0.00382	0.920	20.4 ± 3.5	
900	12	 1.7e-16	11.8088	0.0218	0.0016	22	0.00562	0.959	20.5 ± 1.8	
950	12	 5.6e-16	11.1752	0.0061	0.0032	80	0.01201	0.915	18.5 ± 0.5	
1000	12	 2.5e-15	10.6942	0.0169	0.0031	29	0.04210	0.914	17.7 ± 0.2	
1050	12	 8.1e-15	11.2358	0.0145	0.0051	34	0.13402	0.867	17.6 ± 0.2	
1100	12	 1.9e-14	14.1942	0.0256	0.0155	19	0.30258	0.678	17.4 ± 0.2	
1150	12	 2.5e-14	10.5325	0.0059	0.0027	84	0.60464	0.926	17.6 ± 0.2	
1200	12	 2.0e-14	10.0919	0.0084	0.0013	59	0.86363	0.963	17.6 ± 0.2	
1300	12	 1.1e-14	10.7870	0.0361	0.0020	14	1.00000	0.946	18.4 ± 0.2	
Total fusion age = 17.71 ± 0.16 Ma
Weighted mean age = 17.60 ± 0.15 Ma
Inverse isochron age =17.66 ± 0.16 Ma (MSWD =0.75; 40Ar/36Ar=287.0 ± 3.0)
Steps used: 1000-1200 or 85% ∑ 39Ar

Sample: MD79 Biotite	J=0.0009973
T	t	40(mol)	40/39	37/39	36/39	K/Ca	∑ 39Ar	40Ar*	Age ± 1s Ma	
800	12	 9.5e-15	36.7413	0.0097	0.1148	51	0.05623	0.076	5.0 ± 0.5	
850	12	 3.0e-15	19.5024	0.0002	0.0422	2679	0.08929	0.361	12.6 ± 0.4	
900	12	 5.9e-15	14.4292	0.0007	0.0225	720	0.17815	0.539	13.9 ± 0.2	
950	12	 6.4e-15	12.1571	0.0001	0.0125	9251	0.29248	0.695	15.1 ± 0.2	
1000	12	 4.1e-15	11.3810	0.0001	0.0096	6333	0.37080	0.750	15.3 ± 0.2	
1050	12	 5.4e-15	11.3528	0.0001	0.0083	8355	0.47419	0.785	16.0 ± 0.2	
1100	12	 1.2e-14	11.6072	0.0000	0.0094	18267	0.70037	0.760	15.8 ± 0.2	
1150	12	 1.1e-14	11.3745	0.0000	0.0085	16688	0.90714	0.780	15.9 ± 0.2	
1200	12	 3.7e-15	10.6915	0.0001	0.0048	6032	0.98193	0.867	16.6 ± 0.2	
1300	12	 9.3e-16	11.1960	0.0101	0.0072	49	1.00000	0.810	16.2 ± 0.3	
Total fusion age = 14.92 ± 0.14 Ma
Weighted mean plateau age = 15.88 ± 0.15 Ma
Inverse isochron age =16.89 ± 0.75 Ma (MSWD =0.16; 40Ar/36Ar=231.2 ± 18.7)
Steps used: 1050-1150 or 54% ∑ 39Ar

Sample: MD48A Biotite	J=0.0009740
T	t	40(mol)	40/39	37/39	36/39	K/Ca	∑ 39Ar	40Ar*	Age ± 1s Ma	
700	12	 2.9e-16	10.7970	0.0098	0.0051	50	0.00579	0.860	16.2 ± 0.9	
800	12	 5.2e-17	6.5649	0.0333	0.0029	15	0.00750	0.871	10.0 ± 3.0	
850	12	 3.2e-16	8.3918	0.0071	0.0006	69	0.01556	0.979	14.4 ± 0.6	
900	12	 1.9e-15	9.0540	0.0013	0.0007	382	0.06011	0.978	15.5 ± 0.2	
950	12	 5.4e-15	9.2655	0.0023	0.0014	213	0.18430	0.956	15.5 ± 0.1	
1000	12	 4.7e-15	8.9659	0.0102	0.0015	48	0.29622	0.951	14.9 ± 0.1	
1050	12	 5.5e-15	8.8818	0.0086	0.0008	57	0.42904	0.974	15.1 ± 0.1	
1100	12	 1.0e-14	8.9943	0.0024	0.0008	204	0.66718	0.974	15.3 ± 0.1	
1150	12	 8.1e-15	8.9958	0.0015	0.0006	331	0.86071	0.980	15.4 ± 0.1	
1200	12	 4.7e-15	9.1167	0.0119	0.0011	41	0.97162	0.966	15.4 ± 0.2	
1300	12	 1.2e-15	9.0751	0.0405	0.0010	12	1.00000	0.966	15.3 ± 0.2	
Total fusion age = 15.30 ± 0.14 Ma
Weighted mean plateau age = 15.37 ± 0.14 Ma
Inverse isochron age =15.34 ± 0.22 Ma (MSWD =1.48; 40Ar/36Ar=312.2 ± 131.0)
Steps used: 1100, 1150, 1200, 1300 or 57% ∑ 39Ar

Sample: MD64A Biotite	J=0.0002415
T	t	40(mol)	40/39	37/39	36/39	K/Ca	∑ 39Ar	40Ar*	Age ± 1s Ma	
575	8	 5.1e-14	32.6480	0.0025	0.0044	197	0.22896	0.961	13.6 ± 0.1	
600	8	 2.7e-14	32.8052	0.0030	0.0044	161	0.34713	0.961	13.7 ± 0.1	
650	8	 1.9e-14	33.4274	0.0040	0.0065	122	0.42831	0.942	13.7 ± 0.1	
700	8	 1.5e-14	33.7446	0.0034	0.0078	142	0.49246	0.932	13.7 ± 0.1	
750	8	 1.7e-14	33.4992	0.0019	0.0060	263	0.56742	0.947	13.8 ± 0.1	
800	8	 3.8e-14	32.7294	0.0010	0.0032	510	0.73717	0.971	13.8 ± 0.1	
900	8	 3.4e-14	33.3519	0.0017	0.0057	283	0.88523	0.949	13.7 ± 0.1	
1050	8	 2.5e-14	32.7562	0.0040	0.0029	123	0.99399	0.974	13.8 ± 0.1	
1200	8	 1.6e-15	37.9921	0.0194	0.0189	25	1.00000	0.853	14.1 ± 0.2	
Total fusion age = 13.72 ± 0.12 Ma
Weighted mean age = 13.79 ± 0.13 Ma
Inverse isochron age =13.86 ± 0.15 Ma (MSWD =2.20; 40Ar/36Ar=247.9 ± 17.9)
Steps used: 750, 800, 1050 or 45% ∑ 39Ar

Sample: MD69A Biotite	J=0.0002428
T	t	40(mol)	40/39	37/39	36/39	K/Ca	∑ 39Ar	40Ar*	Age ± 1s Ma	
525	8	 3.7e-14	45.6395	0.0030	0.0547	165	0.15666	0.646	12.9 ± 0.1	
550	8	 2.3e-14	33.8760	0.0014	0.0102	349	0.28905	0.911	13.5 ± 0.1	
600	8	 2.7e-14	32.6259	0.0010	0.0059	510	0.45040	0.947	13.5 ± 0.1	
700	8	 2.2e-14	33.2029	0.0018	0.0075	271	0.57878	0.933	13.5 ± 0.1	
850	8	 5.0e-14	33.1670	0.0028	0.0066	175	0.87292	0.941	13.6 ± 0.1	
950	8	 1.7e-14	33.6039	0.0602	0.0077	8.1	0.97107	0.933	13.7 ± 0.1	
1100	8	 5.0e-15	33.5135	0.0693	0.0051	7.1	1.00000	0.955	14.0 ± 0.1	
Total fusion age = 13.46 ± 0.11 Ma
Weighted mean age = 13.48 ± 0.11 Ma
Inverse isochron age =13.49 ± 0.12 Ma (MSWD =1.87; 40Ar/36Ar=292.2 ± 14.9)
Steps used: 550, 600, 700 or 42% ∑ 39Ar

Sample: MD71 Biotite	J=0.0002375
T	t	40(mol)	40/39	37/39	36/39	K/Ca	∑ 39Ar	40Ar*	Age ± 1s Ma	
500	8	 1.3e-13	51.3395	0.0043	0.0713	114	0.18104	0.590	12.9 ± 0.1	
525	8	 8.2e-14	33.0922	0.0023	0.0058	214	0.35607	0.949	13.4 ± 0.1	
550	8	 7.1e-14	31.9444	0.0019	0.0031	264	0.51323	0.971	13.2 ± 0.1	
575	8	 4.2e-14	32.5183	0.0017	0.0023	282	0.60433	0.979	13.6 ± 0.1	
625	8	 2.7e-14	32.9137	0.0031	0.0040	157	0.66280	0.964	13.5 ± 0.1	
700	8	 2.9e-14	33.6608	0.0034	0.0060	146	0.72443	0.948	13.6 ± 0.1	
800	8	 8.4e-14	33.5919	0.0021	0.0056	231	0.89969	0.950	13.6 ± 0.1	
1000	8	 4.6e-14	33.8711	0.0033	0.0069	148	0.99545	0.940	13.6 ± 0.1	
1200	8	 2.4e-15	37.1866	0.0188	0.0199	26	1.00000	0.842	13.4 ± 0.2	
Total fusion age = 13.39 ± 0.11 Ma
Weighted mean age = 13.60 ± 0.11 Ma
Inverse isochron age =13.59 ± 0.12 Ma (MSWD =3.34; 40Ar/36Ar=297.3 ± 11.4)
Steps used: 575-1000 or 39% ∑ 39Ar

Sample: MD86 Biotite	J=0.0002469
T	t	40(mol)	40/39	37/39	36/39	K/Ca	∑ 39Ar	40Ar*	Age ± 1s Ma	
600	8	 2.5e-13	30.5701	0.0005	0.0047	954	0.52572	0.955	13.0 ± 0.1	
633	8	 4.6e-14	30.2902	0.0006	0.0040	758	0.62266	0.961	12.9 ± 0.1	
666	8	 2.5e-14	30.8092	0.0001	0.0045	5242	0.67429	0.957	13.1 ± 0.1	
700	8	 2.2e-14	30.9417	0.0003	0.0053	1524	0.71934	0.950	13.0 ± 0.1	
733	8	 2.0e-14	31.1468	0.0000	0.0057	<0.001	0.76167	0.946	13.1 ± 0.1	
766	8	 2.6e-14	31.1725	0.0000	0.0060	<0.001	0.81624	0.943	13.0 ± 0.1	
800	8	 3.6e-14	31.2608	0.0000	0.0059	<0.001	0.89100	0.944	13.1 ± 0.1	
833	8	 2.7e-14	31.5594	0.0000	0.0068	<0.001	0.94577	0.937	13.1 ± 0.1	
866	8	 1.4e-14	31.9645	0.0000	0.0090	<0.001	0.97427	0.917	13.0 ± 0.1	
1000	8	 8.5e-15	30.7360	0.0000	0.0032	<0.001	0.99206	0.969	13.2 ± 0.1	
1200	8	 3.8e-15	31.1428	0.0000	0.0039	<0.001	1.00000	0.963	13.3 ± 0.1	
Total fusion age = 13.00 ± 0.06 Ma
Weighted mean age = 12.93 ± 0.06 Ma
Inverse isochron age =12.84 ± 0.08 Ma (MSWD =3.18; 40Ar/36Ar=340.0 ± 23.5)
Steps used: 600, 633, 866 or 65% ∑ 39Ar

Sample: MD97 Biotite 	J=0.0002487
T	t	40(mol)	40/39	37/39	36/39	K/Ca	∑ 39Ar	40Ar*	Age ± 1s Ma	
550	8	 1.7e-13	41.8494	0.0017	0.0411	295	0.27765	0.710	13.3 ± 0.1	
575	8	 7.6e-14	31.7841	0.0013	0.0060	374	0.44150	0.944	13.4 ± 0.1	
600	8	 4.6e-14	31.8760	0.0011	0.0046	451	0.54038	0.957	13.6 ± 0.1	
650	8	 3.3e-14	33.8755	0.0013	0.0063	380	0.60718	0.945	14.3 ± 0.1	
700	8	 2.9e-14	39.7584	0.0010	0.0075	498	0.65641	0.944	16.8 ± 0.1	
800	8	 6.1e-14	33.2952	0.0012	0.0077	406	0.78155	0.932	13.9 ± 0.1	
900	8	 7.8e-14	32.3569	0.0010	0.0071	472	0.94756	0.935	13.5 ± 0.1	
1000	8	 1.9e-14	32.3338	0.0022	0.0059	227	0.98749	0.946	13.7 ± 0.1	
1200	8	 5.9e-15	32.5524	0.0000	0.0035	<0.001	1.00000	0.968	14.1 ± 0.1	
Total fusion age = 13.71 ± 0.06 Ma
Weighted mean age = 13.41 ± 0.06 Ma
Inverse isochron age =13.48 ± 0.12 Ma (MSWD =83.44; 40Ar/36Ar=288.5 ± 29.3)
Steps used: 550, 575 or 44% ∑ 39Ar

Sample: MD52 Biotite	J=0.0009756
T	t	40(mol)	40/39	37/39	36/39	K/Ca	∑ 39Ar	40Ar*	Age ± 1s Ma	
700	12	 3.5e-16	179.5720	0.0000	0.5709	0.0	0.00071	0.060	19.0 ± 0.1	
800	12	 6.2e-16	36.2852	0.0147	0.1025	33	0.00696	0.165	10.5 ± 1.6	
850	12	 1.9e-15	23.9425	0.0031	0.0554	159	0.03674	0.316	13.3 ± 0.5	
900	12	 3.3e-15	9.1757	0.0028	0.0048	174	0.16725	0.846	13.6 ± 0.1	
950	12	 4.6e-15	7.9609	0.0004	0.0007	1113	0.37669	0.975	13.6 ± 0.1	
1000	12	 2.8e-15	7.9264	0.0014	0.0005	344	0.50622	0.981	13.6 ± 0.1	
1050	12	 2.4e-15	7.9923	0.0026	0.0006	192	0.61451	0.977	13.7 ± 0.1	
1100	12	 4.2e-15	7.9691	0.0095	0.0008	52	0.80885	0.970	13.5 ± 0.1	
1150	12	 2.9e-15	8.0564	0.0035	0.0011	140	0.94087	0.960	13.6 ± 0.1	
1200	12	 7.9e-16	8.0073	0.0051	0.0014	96	0.97719	0.949	13.3 ± 0.3	
1300	12	 5.3e-16	8.5104	0.0081	0.0022	60	1.00000	0.923	13.8 ± 0.4	
Total fusion age = 13.57 ± 0.12 Ma
Weighted mean plateau age = 13.60 ± 0.12 Ma
Inverse isochron age =13.61 ± 0.12 Ma (MSWD =0.54; 40Ar/36Ar=292.7 ± 4.3)
Steps used: 850, 900, 950, 1000, 1050, 1100, 1150, 1200 or 97% ∑ 39Ar

Potassium feldspar data
Sample: MD64A	Potassium feldspar	J=0.0002422
T	t	40(mol)	40/39	37/39	36/39	K/Ca	∑ 39Ar	40Ar*	Age ± 1s Ma	
500	20	5.20E-15	57.162	0.0000	0.0255	<0.001	0.01994	0.868	21.55 ± 0.2	
500	30	2.40E-15	35.1534	0.0000	0.0163	<0.001	0.03494	0.863	13.21 ± 0.1	
550	15	3.30E-15	42.2629	0.0000	0.0065	<0.001	0.05223	0.955	17.54 ± 0.1	
550	20	2.10E-15	30.3346	0.0000	0.0039	<0.001	0.0678	0.962	12.70 ± 0.1	
600	20	6.00E-15	35.1571	0.0000	0.0039	<0.001	0.10558	0.967	14.80 ± 0.1	
600	25	3.20E-15	30.5363	0.0000	0.0042	<0.001	0.12879	0.96	12.76 ± 0.1	
650	15	4.00E-15	33.466	0.0044	0.0042	111	0.15548	0.963	14.03 ± 0.1	
650	20	2.50E-15	30.4852	0.0000	0.0028	<0.001	0.17391	0.973	12.92 ± 0.1	
700	15	3.60E-15	34.7569	0.0000	0.004	<0.001	0.19698	0.966	14.61 ± 0.1	
750	15	4.90E-15	37.092	0.0000	0.0077	<0.001	0.226	0.939	15.15 ± 0.1	
775	15	2.80E-15	30.3653	0.0000	0.0015	<0.001	0.2462	0.985	13.03 ± 0.1	
800	15	2.40E-15	30.5308	0.0000	0.0012	<0.001	0.26373	0.989	13.14 ± 0.1	
825	15	2.40E-15	31.7744	0.0000	0.0027	<0.001	0.28044	0.974	13.48 ± 0.1	
850	15	2.60E-15	31.3039	0.0000	0.0022	<0.001	0.29876	0.979	13.34 ± 0.1	
875	15	3.10E-15	32.1506	0.0000	0.0038	<0.001	0.32024	0.965	13.51 ± 0.1	
900	15	3.90E-15	33.479	0.0000	0.0037	<0.001	0.34607	0.967	14.09 ± 0.1	
925	15	4.70E-15	34.3964	0.0000	0.0063	<0.001	0.37618	0.946	14.17 ± 0.1	
950	15	6.10E-15	37.3016	0.0000	0.0073	<0.001	0.41234	0.942	15.29 ± 0.1	
975	15	8.00E-15	39.5406	0.0000	0.0083	<0.001	0.45726	0.938	16.14 ± 0.1	
1000	15	1.10E-14	42.4411	0.0000	0.0103	<0.001	0.51534	0.929	17.14 ± 0.1	
1025	15	2.10E-14	43.8115	0.0011	0.0103	441	0.6221	0.93	17.72 ± 0.1	
1050	15	1.70E-14	40.8107	0.0000	0.0057	<0.001	0.71559	0.959	17.01 ± 0.1	
1075	15	2.20E-14	37.6643	0.0000	0.0035	<0.001	0.84515	0.973	15.94 ± 0.1	
1100	10	2.50E-14	36.3739	0.0000	0.0026	0.0	1	0.979	15.50 ± 0.1	

Sample: MD71 Potassium feldspar	J=0.0002383
T	t	40(mol)	40/39	37/39	36/39	K/Ca	∑ 39Ar	40Ar*	Age ± 1s Ma	
450	15	4.50E-14	770.024	0.0104	1.2161	47	0.00239	0.533	168.4 ± 1.6	
450	20	1.90E-15	76.1345	0.0366	0.1202	13	0.00342	0.533	17.4 ± 0.3	
500	20	5.80E-15	76.1532	0.0121	0.0774	40	0.00651	0.7	22.8 ± 0.2	
500	30	2.20E-15	41.0266	0.0225	0.0325	22	0.00873	0.766	13.5 ± 0.1	
550	15	3.90E-15	48.1968	0.0230	0.0316	21	0.01201	0.806	16.6 ± 0.2	
550	20	2.20E-15	32.0162	0.0000	0.0072	0.0	0.01475	0.934	12.8 ± 0.1	
600	20	6.40E-15	34.247	0.0000	0.0102	0.0	0.02238	0.912	13.4 ± 0.1	
600	25	9.00E-15	30.8379	0.1341	0.0054	3.7	0.03433	0.948	12.5 ± 0.1	
650	15	1.30E-14	31.1155	0.0988	0.0052	5	0.05158	0.95	12.7 ± 0.1	
650	20	1.20E-14	30.3616	0.1067	0.0031	4.6	0.06722	0.97	12.6 ± 0.1	
700	15	1.80E-14	30.9797	0.0735	0.0037	6.7	0.09096	0.965	12.8 ± 0.1	
750	15	5.80E-14	33.7897	0.0266	0.0076	18	0.16159	0.934	13.5 ± 0.1	
775	15	1.90E-14	29.9763	0.0655	0.0013	7.5	0.18787	0.987	12.7 ± 0.1	
800	15	2.20E-14	29.9037	0.0099	0.001	50	0.21745	0.99	12.7 ± 0.1	
825	15	1.90E-14	30.2069	0.0068	0.0015	72	0.24376	0.985	12.8 ± 0.1	
850	15	1.90E-14	30.6578	0.0071	0.0024	69	0.26871	0.977	12.8 ± 0.1	
875	15	1.90E-14	32.1426	0.0047	0.0052	104	0.29298	0.952	13.1 ± 0.1	
900	15	1.70E-14	32.7656	0.0141	0.0062	35	0.31376	0.944	13.3 ± 0.1	
925	15	1.60E-14	35.0476	0.0098	0.0121	50	0.33209	0.898	13.5 ± 0.1	
950	15	2.00E-14	37.6698	0.0099	0.0177	49	0.35403	0.861	13.9 ± 0.1	
975	15	2.60E-14	39.9225	0.0096	0.0224	51	0.38061	0.834	14.3 ± 0.1	
1000	15	3.10E-14	39.6007	0.0059	0.0208	83	0.41303	0.844	14.3 ± 0.1	
1025	15	4.20E-14	39.0089	0.0070	0.019	70	0.45695	0.856	14.3 ± 0.1	
1050	15	5.80E-14	37.0651	0.0050	0.013	98	0.52132	0.896	14.2 ± 0.1	
1075	15	4.60E-14	35.4312	0.0058	0.0099	85	0.57471	0.918	13.9 ± 0.1	
1100	10	3.40E-14	36.1595	0.0024	0.009	206	0.61262	0.926	14.3 ± 0.1	
1100	85	1.20E-13	36.9115	0.0025	0.011	199	0.74386	0.912	14.4 ± 0.1	
1100	145	1.20E-13	37.3256	0.0034	0.0131	145	0.87411	0.897	14.3 ± 0.1	
1100	550	1.20E-13	48.1689	0.0028	0.0493	175	0.97649	0.698	14.4 ± 0.1	
1150	8	6.70E-16	36.5393	0.0698	0.0075	7	0.97724	0.939	14.7 ± 0.4	
1175	8	1.20E-15	36.9074	0.0386	0.0083	13	0.97859	0.933	14.8 ± 0.2	
1200	8	5.70E-15	37.2824	0.0021	0.0097	235	0.98486	0.923	14.7 ± 0.1	
1225	8	7.60E-15	36.8345	0.0093	0.0092	53	0.9933	0.926	14.6 ± 0.1	
1350	8	2.30E-15	40.7085	0.0000	0.0194	0.0	0.99557	0.859	15 ± 0.2	
1450	57	7.40E-15	68.2634	0.0566	0.1031	8.7	1	0.554	16.2 ± 0.2	

Sample: MD86 Potassium feldspar	J=0.0002479
T	t	40(mol)	40/39	37/39	36/39	K/Ca	∑ 39Ar	40Ar*	Age ± 1s Ma	
650	8	7.50E-14	27.2885	0.0106	0.0058	46	0.06735	0.937	11.4 ± 0	
725	8	7.20E-14	25.607	0.0102	0.0026	48	0.13609	0.97	11.1 ± 0	
775	8	5.10E-14	25.7504	0.0111	0.0022	44	0.18484	0.974	11.2 ± 0	
825	8	4.70E-14	26.6138	0.0123	0.0027	40	0.22759	0.97	11.5 ± 0	
875	8	4.10E-14	27.3234	0.0112	0.0038	44	0.2645	0.959	11.7 ± 0	
925	8	4.30E-14	27.969	0.0085	0.0057	58	0.30177	0.94	11.7 ± 0	
975	8	4.90E-14	29.7578	0.0069	0.0089	71	0.34165	0.912	12.1 ± 0	
1000	8	4.20E-14	31.0839	0.0081	0.0113	61	0.37443	0.893	12.4 ± 0	
1025	8	4.60E-14	32.1186	0.0070	0.0129	70	0.40963	0.881	12.6 ± 0	
1050	8	5.60E-14	31.7606	0.0073	0.0113	67	0.45263	0.895	12.7 ± 0	
1075	8	4.90E-14	31.4297	0.0078	0.0092	63	0.49032	0.914	12.8 ± 0	
1100	8	5.40E-14	31.0471	0.0074	0.0075	66	0.53268	0.929	12.8 ± 0	
1125	8	7.40E-14	31.0378	0.0072	0.0066	68	0.59085	0.937	13 ± 0	
1150	8	1.20E-13	30.8941	0.0047	0.0059	103	0.68307	0.944	13 ± 0	
1165	8	1.40E-13	30.71	0.0032	0.0058	152	0.79549	0.944	12.9 ± 0	
1175	8	1.00E-13	30.5604	0.0037	0.006	132	0.87689	0.942	12.8 ± 0	
1200	8	7.60E-14	30.5264	0.0041	0.0055	120	0.93746	0.947	12.9 ± 0	
1225	8	4.10E-14	30.5715	0.0054	0.0053	90	0.97041	0.949	12.9 ± 0	
1250	8	1.50E-14	30.4656	0.0111	0.0055	44	0.98211	0.947	12.9 ± 0	
1275	8	8.70E-15	30.4807	0.0162	0.0057	30	0.98907	0.945	12.8 ± 0	
1400	8	1.40E-14	30.8545	0.0112	0.0053	44	1	0.949	13.1 ± 0	

Sample: MD97	Potassium feldspar	J=0.0002484
T	t	40(mol)	40/39	37/39	36/39	K/Ca	∑ 39Ar	40Ar*	Age ± 1s Ma	
600	8	 1.9e-13	26.6730	0.0127	0.0030	39	0.12190	0.967	11.3 ± 0.0	
625	8	 5.1e-14	25.7962	0.0102	0.0000	48	0.15647	1.000	11.3 ± 0.0	
675	8	 5.4e-14	26.2609	0.0306	0.0000	16	0.19247	1.000	11.3 ± 0.0	
750	8	 7.3e-14	27.5847	0.0247	0.0004	20	0.23829	0.995	11.7 ± 0.0	
825	8	 8.0e-14	29.8203	0.0053	0.0039	93	0.28499	0.961	12.3 ± 0.0	
900	8	 1.4e-13	32.3892	0.0039	0.0109	125	0.36062	0.901	12.7 ± 0.1	
950	8	 1.7e-13	32.0418	0.0049	0.0080	100	0.45036	0.926	13.0 ± 0.1	
975	8	 1.7e-13	31.7494	0.0044	0.0065	111	0.54374	0.939	13.0 ± 0.1	
990	8	 1.6e-13	31.4990	0.0033	0.0055	147	0.63024	0.948	13.0 ± 0.1	
1005	8	 1.6e-13	31.3126	0.0020	0.0046	251	0.71986	0.957	13.1 ± 0.1	
1020	8	 1.5e-13	31.1706	0.0010	0.0038	490	0.80111	0.964	13.1 ± 0.1	
1040	8	 1.3e-13	30.7767	0.0005	0.0025	925	0.87281	0.976	13.1 ± 0.1	
1070	8	 7.4e-14	30.6600	0.0000	0.0000	<0.001	0.91499	1.000	13.2 ± 0.1	
1140	8	 4.4e-14	31.0216	0.0000	0.0000	<0.001	0.93977	1.000	13.4 ± 0.1	
1240	8	 8.1e-14	30.8209	0.0008	0.0000	589	0.98532	1.000	13.5 ± 0.1	
1340	8	 1.3e-14	32.3131	0.0000	0.0000	<0.001	0.99256	1.000	13.9 ± 0.1	
1450	8	 1.4e-14	33.2764	0.0000	0.0000	<0.001	1.00000	1.000	13.7 ± 0.1	

Sample: MD52 Potassium feldspar		J=0.0002400
T	t	40(mol)	40/39	37/39	36/39	K/Ca	∑ 39Ar	40Ar*	Age ± 1s Ma	
600	8	2.20E-14	51.5569	0.0065	0.0239	75	0.02006	0.863	19.2 ± 0.2	
700	8	4.50E-14	38.6241	0.0033	0.0093	148	0.07461	0.929	15.5 ± 0.1	
800	8	4.80E-14	34.3771	0.0038	0.005	128	0.13943	0.957	14.2 ± 0.1	
850	8	1.80E-14	30.9725	0.0036	0.0023	136	0.16613	0.978	13.1 ± 0.1	
900	8	1.60E-14	31.9422	0.0062	0.0036	80	0.18944	0.967	13.3 ± 0.1	
950	8	1.80E-14	33.9274	0.0085	0.0057	57	0.21403	0.951	13.9 ± 0.1	
1000	8	2.70E-14	39.4413	0.0035	0.0102	141	0.2464	0.923	15.7 ± 0.2	
1050	8	2.40E-14	40.1002	0.0068	0.0118	72	0.27386	0.913	15.8 ± 0.2	
1100	8	4.00E-14	40.4821	0.0062	0.0125	80	0.3197	0.909	15.9 ± 0.2	
1150	8	2.00E-13	40.2102	0.0030	0.01	164	0.54725	0.927	16.1 ± 0.2	
1175	8	2.10E-13	37.922	0.0030	0.0104	166	0.80372	0.919	15.0 ± 0.1	
1200	8	9.40E-14	35.0475	0.0041	0.0084	119	0.92834	0.929	14.0 ± 0.1	
1250	8	5.30E-14	34.2527	0.0059	0.0062	83	1.00	0.946	14.0 ± 0.1	
Mineral separates were obtained using magnetic separatory methods, paper shaking, heavy liquids, and hand picking to >99% purity. 40Ar/39Ar samples were wrapped in copper foil, placed in evacuated quartz vials with flux monitor TCR sanidine (assumed age = 27.92 Ma) and irradiated at the TRIGA reactor, Oregon State University. Samples were analyzed at the Stanford University by step-heating in a Ta crucible within a double-vacuum Staudacher-type resistance furnace, gettered by a SAES 707 and ST-172 porous getters and analyzed on a MAP 216 mass spectrometer fitted with a Baur-Signer source and a Johnston MM1 multiplier with a sensitivity of 2.0x10-14 moles/volt. Temperatures were monitored with a tungsten-rhenium thermocouple to ±5°C.  Typical extraction line blanks vary from 2.0x10-16 moles 40Ar at <1000°C to 6.0x10-16 moles 40Ar at 1300°C. Errors reported are 1s. See Hacker (1993) for method of calculating isotopic abundances, corrections and uncertainties. t = dwell time in minutes; 40(mol) = moles corrected for blank and reactor-produced 40; ratios are corrected for blanks, decay, and interference; ∑39Ar is cumulative; 40Ar* = radiogenic fraction. 

Reference

Hacker, B. R. 1993. Evolution of the northern Sierra nevada metamorphic belt: Petrologic, structural, and Ar/Ar constraints. Geological Society of America Bulletin, 105, 637–656.