. 2020 Aug 5;15(8):e0235421. doi: 10.1371/journal.pone.0235421

Table 3. Mn and Fe areal density, normalized areal density, Fe vs. Mn correlation, and Mn/Fe ratios from pXRF measurements on rock varnish at Aberdeen volcanic area, Fossil Falls (FF), Little Lake (LL), and Little Lake Hotel (LLH).

[Avg.: arithmetic average, S.D.: standard deviation, S.E.: standard error].

Site	N	D_Mn		D_Fe		Slope Mn/Fe		Intercept		R²	Mn/Fe
		Avg.	S.D.	Avg.	S.D.	Avg.	S.E.	Avg.	S.E.		Avg.	S.D.
Aberdeen lava flows	45	300	150	180	160	1.64	0.28	12.3	52.3	0.31	1.62	0.24
Flow surfaces at Rose Valley sites FF, LL, and LLH
Red Hill	58	560	310	620	230	---	---	---	---	---	0.89	0.60
Red Hill scoured	16	340	200	150	200	1.81	0.62	-138	190	0.39	1.19	0.91
Little Lake basalt	26	750	280	890	240	1.90	0.72	-939	646	0.05	0.84	0.39
All intact varnish	103	550	290	630	320	1.01	0.16	-47	109	0.04	0.86	0.63
Petroglyphs	107	160	170	300	180	0.93	0.08	-114	26	0.43	0.57	0.51
All data	262	350	310	400	310	1.00	0.07	-43	32	0.28	1.01	1.00
Normalized densities on petroglyphs
	N	N_Mn		N_Fe		Slope Mn/Fe		Intercept		R²
		Avg.	S.D.	Avg.	S.D.	Avg.	S.E.	Avg.	S.E.
Individual measurements	106	26.6	28.4	41.6	26.6	1.16	0.18	-22	6.6	0.22
Same, w/o outliers^a	94	18.1	11.6	37.8	19.0	0.32	0.06	5.9	2.5	0.11
Element averages	22	23.3	22.8	41.6	18.5	1.40	0.32	-35	14	0.34
Same, w/o outliers^a	20	17.7	10.8	38.8	16.9	0.55	0.14	-3.2	6.1	0.24

^a) Data from FFS-2 and LLA-1 removed as outliers