Table 1.

Microstructural data for olivine in the Shiant Isles Main Sill (see “Appendix” for definitions of the different measures of grain size)

			Individual olivine grains												Olivine clusters
Sample	height (m)	vol.%	n g	Irreg	Σd	Σd2	Σd3	Σd4	D4,3	D3,2	D3,1	Corrected D4,3	σ	e	n c	Σd	Σd2	Σd3	Σd4	D4,3	D3,2	D3,1	Corrected D4,3
Lower picrite
SC744	2.28	20.0	249	1.15	71.11	25.32	11.12	5.93	0.50	0.42	0.39	0.44 ± 0.04	0.41	0.07	–	–	–	–	–	–	–	–	–
SC728	4.17	36.3	385	1.10	106.43	37.30	15.87	7.82	0.48	0.41	0.38	0.41 ± 0.03	0.39	0.05	–	–	–	–	–	–	–	–	–
SC681	8.70	43.6	429	1.09	116.90	41.50	18.33	9.62	0.50	0.42	0.38	0.44 ± 0.03	0.42	0.06	–	–	–	–	–	–	–	–	–
SC656	12.27	54.0	622	1.10	180.90	63.59	26.40	12.62	0.47	0.41	0.39	0.39 ± 0.02	0.36	0.04	–	–	–	–	–	–	–	–	–
SC598	17.91	51.2	395	1.12	119.74	45.19	20.69	11.15	0.52	0.44	0.41	0.44 ± 0.03	0.39	0.05	–	–	–	–	–	–	–	–	–
SC560	21.16	43.0	364	1.11	130.01	57.98	30.63	18.28	0.60	0.53	0.49	0.50 ± 0.03	0.36	0.05	–	–	–	–	–	–	–	–	–
SC539	22.43	36.3	335	1.09	129.92	61.79	35.23	23.54	0.65	0.56	0.53	0.54 ± 0.03	0.38	0.05	–	–	–	–	–	–	–	–	–
Picrodolerite/crinanite unit (PCU)
SC533	22.92	48.5	431	1.07	105.63	41.72	23.60	17.27	0.64	0.47	0.38	0.66 ± 0.08	0.57	0.12	–	–	–	–	–	–	–	–	–
SC518	23.64	48.6	601	1.09	144.46	54.06	29.36	21.26	0.61	0.44	0.37	0.64 ± 0.07	0.58	0.11	–	–	–	–	–	–	–	–	–
SC492	26.42	43.3	617	1.16	134.95	43.41	23.28	14.73	0.61	0.38	0.32	0.71 ± 0.11	0.69	0.19	–	–	–	–	–	–	–	–	–
SC459	29.72	40.0	517	1.07	98.05	30.37	14.13	8.84	0.53	0.36	0.30	0.57 ± 0.07	0.61	0.14	256	63.60	30.67	22.73	21.55	0.84	0.57	0.42	0.91 ± 0.19
S81/10	32.95	32.4	519	1.07	98.23	26.43	9.82	4.78	0.42	0.32	0.28	0.42 ± 0.04	0.53	0.09	236	57.58	23.10	13.51	9.90	0.66	0.47	0.38	0.69 ± 0.12
S81/12	35.08	24.5	516	1.14	101.22	29.24	12.33	7.14	0.48	0.34	0.29	0.50 ± 0.06	0.58	0.12	228	64.23	29.80	20.33	17.85	0.77	0.55	0.44	0.81 ± 0.15
S81/14	38.43	23.0	455	1.09	90.84	26.55	11.10	6.11	0.47	0.34	0.30	0.49 ± 0.06	0.56	0.12	188	55.06	26.02	17.01	13.49	0.74	0.56	0.46	0.74 ± 0.12
S81/15	39.95	21.0	551	1.16	114.02	34.39	15.42	9.70	0.51	0.36	0.31	0.54 ± 0.06	0.60	0.13	202	64.35	35.22	28.74	31.54	0.92	0.64	0.51	0.97 ± 0.20
S81/17	42.40	22.8	609	1.19	121.84	36.53	19.26	17.20	0.60	0.35	0.30	0.72 ± 0.14	0.72	0.23	197	64.50	37.45	37.18	54.26	1.12	0.68	0.53	1.29 ± 0.47
S81/19	45.57	16.9	304	1.14	81.32	30.17	15.63	11.17	0.59	0.44	0.39	0.59 ± 0.08	0.54	0.13	91	57.44	50.57	54.96	68.35	1.23	1.04	0.91	1.12 ± 0.14
SC253	49.28	20.0	216	1.19	62.55	23.67	11.44	6.82	0.55	0.45	0.41	0.50 ± 0.05	0.45	0.10	64	36.98	28.99	30.75	41.88	1.20	0.92	0.82	1.18 ± 0.28
S81/22	52.88	21.8	171	1.17	56.10	24.95	14.81	10.99	0.67	0.52	0.47	0.65 ± 0.09	0.50	0.14	41	25.58	21.60	22.88	28.39	1.20	0.99	0.89	1.10 ± 0.22
S81/24	56.57	16.1	275	1.17	82.10	35.57	20.62	15.17	0.66	0.51	0.44	0.63 ± 0.07	0.50	0.11	92	60.89	56.47	67.14	96.26	1.35	1.09	0.96	1.26 ± 0.19
S81/25	60.50	11.8	376	1.20	108.12	41.96	20.61	12.29	0.56	0.46	0.41	0.50 ± 0.04	0.44	0.07	37	34.02	42.21	59.70	91.20	1.60	1.46	1.31	1.36 ± 0.16
S81/26	63.64	8.8	221	1.29	90.59	51.05	36.95	32.72	0.82	0.66	0.59	0.75 ± 0.08	0.46	0.10	57	45.12	51.91	73.42	117.98	1.60	1.36	1.17	1.48 ± 0.23
S81/27	65.86	20.1	247	1.27	103.01	62.83	52.73	56.87	0.95	0.72	0.62	0.94 ± 0.13	0.53	0.13	36	37.60	63.26	134.82	329.63	2.41	1.98	1.62	2.22 ± 0.51
S81/29	69.68	10.0	126	1.50	63.65	44.97	39.26	39.08	0.99	0.83	0.73	0.87 ± 0.10	0.41	0.11	33	30.92	45.23	81.68	166.95	2.04	1.72	1.43	1.88 ± 0.40
S81/30	72.27	6.7	219	1.17	84.64	48.85	37.69	35.41	0.87	0.68	0.58	0.84 ± 0.11	0.50	0.12	36	34.57	48.78	87.28	182.93	2.03	1.66	1.43	1.94 ± 0.46
SC1160	148.71	11.7	127	–	60.52	52.90	66.19	99.30	1.42	1.03	0.79	1.46 ± 0.32	0.56	0.22	56	43.34	52.93	80.73	138.93	1.73	1.44	1.19	1.63 ± 0.27
SC1131	152.63	9.1	454	–	125.02	48.01	23.89	14.24	0.56	0.45	0.40	0.52 ± 0.04	0.47	0.07	158	74.65	48.46	39.02	36.58	0.91	0.76	0.68	0.87 ± 0.08
SC1081	156.16	9.2	249	–	79.58	37.14	22.25	15.66	0.68	0.55	0.47	0.62 ± 0.06	0.46	0.09	144	61.87	37.13	27.67	24.13	0.84	0.71	0.62	0.81 ± 0.08
SC1072	157.29	8.9	154	–	59.61	27.28	13.95	7.73	0.58	0.54	0.52	0.44 ± 0.03	0.27	0.05	105	49.50	27.37	17.06	11.63	0.71	0.65	0.63	0.65 ± 0.04
SC1062	158.11	11.1	190	–	60.43	26.37	14.13	8.70	0.61	0.51	0.46	0.53 ± 0.05	0.41	0.08	156	55.98	26.27	14.71	9.29	0.63	0.55	0.50	0.58 ± 0.04

Height gives the stratigraphic height in the composite profile of Gibb and Henderson (1996). The number of individual grains and the number of olivine clusters analysed in each sample is given by n _g and n _c. “Irreg” gives the irregularity of the grains (see text for explanation). The olivine mode (vol.%) is taken from Gibb and Henderson (1996) and Henderson et al. (2000): those values in italics were either interpolated from available data or measured from thin sections as part of this study