Table T2. 40Ar/39Ar analytical results. (See table notes. Continued on next two pages.)

Table T2. ⁴⁰Ar/³⁹Ar analytical results.

Hole, core

Mineral

J

Weight
(g)

Grain size
(µm)

Temp
(°C)

⁴⁰Ar/³⁹Ar^†

³⁷Ar/³⁹Ar^‡

³⁶Ar/³⁹Ar^†

³⁹Ar_k (counts)**

Cumulative ³⁹Ar released (%)

⁴⁰Ar*^‡(%)

⁴⁰Ar*/³⁹Ar_K

Age
(Ma)

± 1

180-

1110B-3X K-feldspar 0.00076393 0.012126 single grain

450 73.870 0.201 0.227 6958 2.91 9.9 7.31 10.0 0.9

470 15.392 0.738 0.027 2816 4.08 49.8 7.66 10.5 0.4

490 13.074 1.096 0.018 2510 5.13 60.4 7.88 10.8 0.5

520 12.638 1.253 0.015 3000 6.39 65.9 8.32 11.4 0.4

550 12.464 0.599 0.015 1924 7.19 64.4 8.02 11.0 0.4

600 16.423 0.245 0.028 2991 8.44 49.3 8.1 11.1 0.5

650 13.672 0.089 0.018 4549 10.34 60.5 8.26 11.3 0.3

700 11.007 0.031 0.011 4612 12.27 70 7.69 10.6 0.2

775 11.083 0.015 0.010 7256 15.3 72.9 8.06 11.1 0.2

850 10.246 0.056 0.006 9955 19.46 82.6 8.44 11.6 0.1

890 10.777 0.003 0.009 9469 23.42 76.3 8.21 11.3 0.2

930 11.322 0.004 0.010 11755 28.33 73.2 8.27 11.4 0.1

970 11.703 0.003 0.012 14572 34.42 70.6 8.24 11.3 0.1

1010 11.885 0.002 0.012 24044 44.47 70.4 8.34 11.5 0.1

1035 11.859 0.001 0.012 20479 53.03 70.4 8.33 11.4 0.1

1060 11.945 0.001 0.011 34425 67.42 74.3 8.85 12.2 0.1

1080 12.000 0.001 0.010 40600 84.39 74.7 8.95 12.3 0.1

1130 12.109 0.001 0.009 33518 98.39 77.9 9.41 12.9 0.1

1180 14.713 0.000 0.016 2468 99.43 67.5 9.91 13.6 0.4

1300 20.976 0.005 0.041 1246 99.95 42.7 8.95 12.3 1.1

1500 2828.098 0.138 9.389 100 99.99 2.8 79.42 106.3 46.7

1600 11427.723 0.128 38.861 27 100.00 0.4 50.83 68.7 122.2

Integrated Age = 11.9 ± 0.2 Ma

1111A-16R K-feldspar 0.00076335 0.011378 single grain

450 113.668 0.051 0.354 5293 2.87 8.7 9.93 13.6 1.4

480 22.440 0.131 0.050 2607 4.29 34.9 7.81 10.7 0.5

510 19.224 0.127 0.038 2270 5.52 42.0 8.05 11.1 0.9

550 18.721 0.078 0.034 3377 7.35 47.3 8.85 12.1 0.4

600 22.836 0.011 0.042 4751 9.93 46.4 10.58 14.5 0.3

650 18.244 0.008 0.028 5395 12.86 55.2 10.05 13.8 0.3

700 41.701 0.006 0.106 6405 16.33 25.6 10.66 14.6 0.6

750 15.956 0.008 0.019 6035 19.61 64.5 10.27 14.1 0.3

800 15.814 0.005 0.019 5675 22.69 64.8 10.23 14.0 0.2

850 19.712 0.005 0.034 5777 25.82 49.2 9.68 13.3 0.3

900 24.505 0.009 0.050 6509 29.36 39.8 9.74 13.4 0.3

950 22.650 0.007 0.046 8974 34.23 41.2 9.32 12.8 0.3

990 21.944 0.006 0.041 13437 41.52 45.7 10.01 13.7 0.2

1020 22.397 0.004 0.041 20514 52.65 45.8 10.25 14.1 0.2

1050 19.220 0.005 0.029 49135 79.31 55.2 10.58 14.5 0.1

1080 19.523 0.003 0.030 18617 89.42 54.3 10.63 14.6 0.3

1150 20.439 0.004 0.031 11546 95.68 55.0 11.23 15.4 0.3

1300 18.141 0.004 0.023 5644 98.75 62.5 11.32 15.5 0.4

1500 166.899 0.005 0.544 2312 100.00 4.5 7.57 10.4 2.4

Integrated Age = 14.1 ± 0.3 Ma

1109D-45R Plagioclase 0.00075457 0.014988 106-150

450 802.398 39.214 102.144 13 1.25 -0.3 -102.4 — 103.4

600 288.718 67.316 0.760 56 6.8 24.6 76.3 98.4 18.2

700 168.474 98.485 0.456 113 18.0 24.9 46.7 60.5 10.7

850 105.678 97.350 0.234 327 50.2 41.7 49.1 64.3 6.2

950 100.245 77.242 0.198 201 70.2 47.7 52 69.3 6.6

1100 300.400 52.278 0.795 201 90.0 23.7 75.4 98.9 7.6

1300* 748.150 68.171 2.259 139 100.0 12.2 98.6 128.8 26.6

Integrated Age = 79.3 ± 11.0 Ma

1117A-11R Plagioclase 0.00075585 0.014965 106-150

450 3758.641 0.479 12.280 58 2.48 4.4 163.4 210.1 56.6

600 232.905 4.461 0.559 101 6.82 29.9 69.8 92.8 13.9

700 140.379 4.839 0.319 226 16.46 33.7 47. 5 63.7 10.6

850 67.217 1.320 0.093 483 37.1 59.7 40.1 53.9 2.7

950 53.154 1.701 0.063 452 56.41 65.6 34.8 46.9 2.5

1050 156.368 4.862 0.289 253 67.22 46.1 72.3 96.0 5.4

1300 436.823 9.244 1.140 683 96.41 23.8 104.8 137.5 5.7

1500 415.226 5.630 1.112 84 100 21.7 90.6 119.5 19.7

Integrated Age = 90.4 ± 7.0 Ma

1117-alt Plagioclase 0.000774677 0.013526 106-150

450 182.914 6.582 0.510 593 4.44 18.6 34.2 45.5 5.3

600 62.599 3.030 0.093 4882 41.0 57.1 35.8 47.5 0.8

700 37.008 1.031 0.023 2490 59.7 82.4 30.5 40.6 0.9

850 37.735 1.382 0.037 506 63.4 71.5 27.0 35.9 1.7

950 40.416 2.706 0.042 1093 71.6 71.1 28.4 37.9 1.0

1100 79.461 8.203 0.140 1364 81.8 49.2 39.3 52.2 1.3

1300 77.859 7.197 0.131 2153 98.0 51.4 40.2 53.4 1.3

1500 318.558 11.183 0.938 272 100.0 14.1 45.3 60.1 7.0

Integrated Age = 46.6 ± 1.3 Ma

1118A-70R Plagioclase 0.0007567 0.013546 75-106

450 598.933 0.511 1.959 334 3.74 4.5 27.2 34.6 9.5

600 93.127 1.040 0.217 2094 27.2 31.9 29.7 39.9 1.5

700 76.929 2.042 0.188 1148 40.12 28.9 22.3 29.6 1

775 72.863 2.686 0.179 602 46.87 29.2 21.3 27.9 1.8

850 80.975 3.061 0.199 525 52.8 28.9 23.5 31.0 2

925 100.479 1.696 0.260 522 58.6 25.2 25.3 33.2 3.9

1000 76.316 1.805 0.174 555 64.9 33.9 25.8 34.5 3.1

1100 294.640 3.560 0.890 1736 84.3 11.9 35.2 47.3 3.7

1175 458.102 6.595 1.490 1061 96.2 5.0 22.8 30.6 7.6

1250 439.110 6.309 1.372 235 98.9 9.0 39.8 51.5 11.5

1375 510.220 5.260 1.513 73 99.7 13.9 71.2 90.8 22.1

1500 3278.937 14.120 11.309 28 100 -0.5 -16.9 — 23.1

Integrated Age = 37.2 ± 3.7 Ma

Total Fusion Analyses

1108B-6R Feldspar 0.00089726 0.00162 75-106 1500 11.10 0.12 0.03 10020 100 11.7 1.3 2.1 0.3

1108B-6R Biotite 0.00090429 0.001398 75-106 1350 9.62 0.04 0.03 6800 100 16.3 1.56 2.6 0.2

1109D-45R Plagioclase 0.00075439 0.001064 106-150 1500 1103.916 67.971 3.392 110 100 10.5 123.8 161.1 35.1

1117A-11R Plagioclase 0.00075532 0.000835 106-150 1500 1472.471 5.305 4.901 150 100 2.6 38.3 51.4 22.6

1117-alt Plagioclase 0.00075180 0.001078 106-150 1500 176.672 3.804 0.465 920 100 23.1 40.9 54.7 3.7

1118A-70R Plagioclase 0.00075655 0.001134 75-106 1500 4194.136 3.003 1.351 641 100 5.74 24.1 32.7 5.8

1110B-03X K-feldspar 0.00076129 0.001248 whole grain 1500 20.378 0.043 0.038 24275 100 44.9 9.14 12.5 0.2

1111A-16R K-feldspar 0.00076513 0.000883 whole grain 1500 56.320 0.004 0.157 16122 100 18.6 10.5 14.4 0.6

Hole, core	Mineral	J	Weight (g)	Grain size (µm)	Temp (°C)	⁴⁰Ar/³⁹Ar^†	³⁷Ar/³⁹Ar^‡	³⁶Ar/³⁹Ar^†	³⁹Ar_k (counts)**	Cumulative ³⁹Ar released (%)	⁴⁰Ar*^‡(%)	⁴⁰Ar*/³⁹Ar_K	Age (Ma)	± 1
180-
1110B-3X	K-feldspar	0.00076393	0.012126	single grain
					450	73.870	0.201	0.227	6958	2.91	9.9	7.31	10.0	0.9
					470	15.392	0.738	0.027	2816	4.08	49.8	7.66	10.5	0.4
					490	13.074	1.096	0.018	2510	5.13	60.4	7.88	10.8	0.5
					520	12.638	1.253	0.015	3000	6.39	65.9	8.32	11.4	0.4
					550	12.464	0.599	0.015	1924	7.19	64.4	8.02	11.0	0.4
					600	16.423	0.245	0.028	2991	8.44	49.3	8.1	11.1	0.5
					650	13.672	0.089	0.018	4549	10.34	60.5	8.26	11.3	0.3
					700	11.007	0.031	0.011	4612	12.27	70	7.69	10.6	0.2
					775	11.083	0.015	0.010	7256	15.3	72.9	8.06	11.1	0.2
					850	10.246	0.056	0.006	9955	19.46	82.6	8.44	11.6	0.1
					890	10.777	0.003	0.009	9469	23.42	76.3	8.21	11.3	0.2
					930	11.322	0.004	0.010	11755	28.33	73.2	8.27	11.4	0.1
					970	11.703	0.003	0.012	14572	34.42	70.6	8.24	11.3	0.1
					1010	11.885	0.002	0.012	24044	44.47	70.4	8.34	11.5	0.1
					1035	11.859	0.001	0.012	20479	53.03	70.4	8.33	11.4	0.1
					1060	11.945	0.001	0.011	34425	67.42	74.3	8.85	12.2	0.1
					1080	12.000	0.001	0.010	40600	84.39	74.7	8.95	12.3	0.1
					1130	12.109	0.001	0.009	33518	98.39	77.9	9.41	12.9	0.1
					1180	14.713	0.000	0.016	2468	99.43	67.5	9.91	13.6	0.4
					1300	20.976	0.005	0.041	1246	99.95	42.7	8.95	12.3	1.1
					1500	2828.098	0.138	9.389	100	99.99	2.8	79.42	106.3	46.7
					1600	11427.723	0.128	38.861	27	100.00	0.4	50.83	68.7	122.2
											Integrated Age = 11.9 ± 0.2 Ma
1111A-16R	K-feldspar	0.00076335	0.011378	single grain
					450	113.668	0.051	0.354	5293	2.87	8.7	9.93	13.6	1.4
					480	22.440	0.131	0.050	2607	4.29	34.9	7.81	10.7	0.5
					510	19.224	0.127	0.038	2270	5.52	42.0	8.05	11.1	0.9
					550	18.721	0.078	0.034	3377	7.35	47.3	8.85	12.1	0.4
					600	22.836	0.011	0.042	4751	9.93	46.4	10.58	14.5	0.3
					650	18.244	0.008	0.028	5395	12.86	55.2	10.05	13.8	0.3
					700	41.701	0.006	0.106	6405	16.33	25.6	10.66	14.6	0.6
					750	15.956	0.008	0.019	6035	19.61	64.5	10.27	14.1	0.3
					800	15.814	0.005	0.019	5675	22.69	64.8	10.23	14.0	0.2
					850	19.712	0.005	0.034	5777	25.82	49.2	9.68	13.3	0.3
					900	24.505	0.009	0.050	6509	29.36	39.8	9.74	13.4	0.3
					950	22.650	0.007	0.046	8974	34.23	41.2	9.32	12.8	0.3
					990	21.944	0.006	0.041	13437	41.52	45.7	10.01	13.7	0.2
					1020	22.397	0.004	0.041	20514	52.65	45.8	10.25	14.1	0.2
					1050	19.220	0.005	0.029	49135	79.31	55.2	10.58	14.5	0.1
					1080	19.523	0.003	0.030	18617	89.42	54.3	10.63	14.6	0.3
					1150	20.439	0.004	0.031	11546	95.68	55.0	11.23	15.4	0.3
					1300	18.141	0.004	0.023	5644	98.75	62.5	11.32	15.5	0.4
					1500	166.899	0.005	0.544	2312	100.00	4.5	7.57	10.4	2.4
									Integrated Age = 14.1 ± 0.3 Ma
1109D-45R	Plagioclase	0.00075457	0.014988	106-150
					450	802.398	39.214	102.144	13	1.25	-0.3	-102.4	—	103.4
					600	288.718	67.316	0.760	56	6.8	24.6	76.3	98.4	18.2
					700	168.474	98.485	0.456	113	18.0	24.9	46.7	60.5	10.7
					850	105.678	97.350	0.234	327	50.2	41.7	49.1	64.3	6.2
					950	100.245	77.242	0.198	201	70.2	47.7	52	69.3	6.6
					1100	300.400	52.278	0.795	201	90.0	23.7	75.4	98.9	7.6
					1300*	748.150	68.171	2.259	139	100.0	12.2	98.6	128.8	26.6
									Integrated Age = 79.3 ± 11.0 Ma
1117A-11R	Plagioclase	0.00075585	0.014965	106-150
					450	3758.641	0.479	12.280	58	2.48	4.4	163.4	210.1	56.6
					600	232.905	4.461	0.559	101	6.82	29.9	69.8	92.8	13.9
					700	140.379	4.839	0.319	226	16.46	33.7	47. 5	63.7	10.6
					850	67.217	1.320	0.093	483	37.1	59.7	40.1	53.9	2.7
					950	53.154	1.701	0.063	452	56.41	65.6	34.8	46.9	2.5
					1050	156.368	4.862	0.289	253	67.22	46.1	72.3	96.0	5.4
					1300	436.823	9.244	1.140	683	96.41	23.8	104.8	137.5	5.7
					1500	415.226	5.630	1.112	84	100	21.7	90.6	119.5	19.7
									Integrated Age = 90.4 ± 7.0 Ma
1117-alt	Plagioclase	0.000774677	0.013526	106-150
					450	182.914	6.582	0.510	593	4.44	18.6	34.2	45.5	5.3
					600	62.599	3.030	0.093	4882	41.0	57.1	35.8	47.5	0.8
					700	37.008	1.031	0.023	2490	59.7	82.4	30.5	40.6	0.9
					850	37.735	1.382	0.037	506	63.4	71.5	27.0	35.9	1.7
					950	40.416	2.706	0.042	1093	71.6	71.1	28.4	37.9	1.0
					1100	79.461	8.203	0.140	1364	81.8	49.2	39.3	52.2	1.3
					1300	77.859	7.197	0.131	2153	98.0	51.4	40.2	53.4	1.3
					1500	318.558	11.183	0.938	272	100.0	14.1	45.3	60.1	7.0
									Integrated Age = 46.6 ± 1.3 Ma
1118A-70R	Plagioclase	0.0007567	0.013546	75-106
					450	598.933	0.511	1.959	334	3.74	4.5	27.2	34.6	9.5
					600	93.127	1.040	0.217	2094	27.2	31.9	29.7	39.9	1.5
					700	76.929	2.042	0.188	1148	40.12	28.9	22.3	29.6	1
					775	72.863	2.686	0.179	602	46.87	29.2	21.3	27.9	1.8
					850	80.975	3.061	0.199	525	52.8	28.9	23.5	31.0	2
					925	100.479	1.696	0.260	522	58.6	25.2	25.3	33.2	3.9
					1000	76.316	1.805	0.174	555	64.9	33.9	25.8	34.5	3.1
					1100	294.640	3.560	0.890	1736	84.3	11.9	35.2	47.3	3.7
					1175	458.102	6.595	1.490	1061	96.2	5.0	22.8	30.6	7.6
					1250	439.110	6.309	1.372	235	98.9	9.0	39.8	51.5	11.5
					1375	510.220	5.260	1.513	73	99.7	13.9	71.2	90.8	22.1
					1500	3278.937	14.120	11.309	28	100	-0.5	-16.9	—	23.1
									Integrated Age = 37.2 ± 3.7 Ma
Total Fusion Analyses
1108B-6R	Feldspar	0.00089726	0.00162	75-106	1500	11.10	0.12	0.03	10020	100	11.7	1.3	2.1	0.3
1108B-6R	Biotite	0.00090429	0.001398	75-106	1350	9.62	0.04	0.03	6800	100	16.3	1.56	2.6	0.2
1109D-45R	Plagioclase	0.00075439	0.001064	106-150	1500	1103.916	67.971	3.392	110	100	10.5	123.8	161.1	35.1
1117A-11R	Plagioclase	0.00075532	0.000835	106-150	1500	1472.471	5.305	4.901	150	100	2.6	38.3	51.4	22.6
1117-alt	Plagioclase	0.00075180	0.001078	106-150	1500	176.672	3.804	0.465	920	100	23.1	40.9	54.7	3.7
1118A-70R	Plagioclase	0.00075655	0.001134	75-106	1500	4194.136	3.003	1.351	641	100	5.74	24.1	32.7	5.8
1110B-03X	K-feldspar	0.00076129	0.001248	whole grain	1500	20.378	0.043	0.038	24275	100	44.9	9.14	12.5	0.2
1111A-16R	K-feldspar	0.00076513	0.000883	whole grain	1500	56.320	0.004	0.157	16122	100	18.6	10.5	14.4	0.6

Notes: J = irradiation parameter. = 5.543 × 10^-10/yr. * = 1500°C step yielded insufficient amount of argon for age calculation, † = corrected for line blank, ‡ = corrected for line blank and ³⁷Ar decay, ** = sensitivity based on air aliquot 3.965 × 10^-14 mol/count. Correction factors used to account for interfering nuclear reactions for all samples except Core 180-1108B-6R feldspar and biotite (see below) are: (³⁶Ar/³⁷Ar)_Ca = 0.000242 ± 0.000084, (³⁸Ar/³⁷Ar)_Ca = 0.00193 ± 0.000042, (³⁹Ar/³⁷Ar)_Ca = 0.0010709 ± 0.0001023, (⁴⁰Ar/³⁹Ar)_K = 0.0199 ± 0.0087, (³⁸Ar/³⁹Ar)_K = 0.012542 ± 0.000057. Correction factors used to account for interfering nuclear reactions for Core 180-1108B-6R feldspar and biotite are: (³⁶Ar/³⁷Ar)_Ca = 0.00045 ± 0.00015, (³⁸Ar/³⁷Ar)_Ca = 0.00042 ± 0.00014, (³⁹Ar/³⁷Ar)_Ca = 0.00118 ± 0.0004, (⁴⁰Ar/³⁹Ar)_K = 0.0416 ± 0.0054, (³⁸Ar/³⁹Ar)_K = 0.0163 ± 0.0001.