Table 2.

Parameters of the linear regression model estimating the relations between first-order kernel scalar product amplitude density values and age in rings 2 and 3. For numbering of the hexagonal areas see Fig. 1. Parameters shown: R², proportion of variation explained by regression; b, slope (nV/deg² per year); a, intercept (nV/deg²); CD,change per decade (%; see text). Range was calculated as the ratio (%) of the maximal to the minimal value for each parameter. NB: Probability (P; from the F-test of the analysis of variance for the regression) was less than 0.0001 for all areas

Areas in ring 2		N-41	N-42	N-51	N-53	N-62	N-63							Range (%)
Scalar	R2	0.226	0.321	0.441	0.439	0.419	0.429							195.2%
product	b	−0.095	−0.104	−0.175	−0.129	−0.128	−0.118							54.5%
amplitude	a	17.47	16.11	23.30	17.97	16.86	16.04							145.3%
density	CD	−5.46%	−6.42%	−7.52%	−7.16%	−7.59%	−7.36%							72.0%
N1P1	R2	0.259	0.408	0.505	0.471	0.496	0.497							195.5%
amplitude	b	−0.355	−0.427	−0.587	−0.474	−0.483	−0.438							60.5%
	a	66.29	64.81	81.88	67.67	65.61	61.76							132.6%
	CD	−5.36%	−6.59%	−7.17%	−7.00%	−7.37%	−7.10%							72.7%
Areas in ring 3		N-30	N-31	N-32	N-40	N-43	N-50	N-54	N-61	N-64	N-72	N-73	N-74	Range (%)
Scalar	R2	0.206	0.228	0.269	0.287	0.323	0.366	0.319	0.413	0.346	0.349	0.403	0.348	200.5%
product	b	−0.049	−0.052	−0.047	−0.077	−0.059	−0.091	−0.055	−0.083	−0.066	−0.059	−0.069	−0.057	52.1%
amplitude	a	9.71	9.84	8.62	13.27	10.21	13.76	9.8	12.48	10.66	9.51	10.62	9.33	159.6%
density	CD	−5.09%	−5.29%	−5.50%	−5.83%	−5.76%	−6.61%	−5.56%	−6.65%	−6.17%	−6.15%	−6.47%	−6.06%	76.9%
N1P1	R2	0.275	0.259	0.339	0.366	0.390	0.431	0.309	0.469	0.414	0.398	0.472	0.374	182.0%
amplitude	b	−0.222	−0.219	−0.224	−0.325	−0.241	−0.337	−0.230	−0.315	−0.259	−0.245	−0.308	−0.232	64.9%
	a	40.93	41.17	38.37	53.02	41.51	51.74	40.22	48.52	42.49	37.64	42.10	36.78	138.2%
	CD	−5.43%	−5.31%	−5.83%	−6.13%	−5.79%	−6.51%	−5.72%	−6.49%	−6.11%	−6.51%	−7.31%	−6.29%	81.5%