(a)
(b)
(c)
(d)
(e)
(f)
Figure 1: Scale comparisons (1 : 1) of previously reported “tubular” bioalteration microtextures in submarine basaltic glass (a, c, and e) with abiotic corrosion microtextures (alpha-recoil track etch-tunnels) in DSDP 418A basaltic glass (this study) (b, d, and f). All images (a–f) are photomicrographs of polished petrographic sections of submarine basaltic glasses taken in plane polarized light (uncrossed nicols). (a) and (c) are from [11] (sample DSDP-418A-62-4-[64–70]), and (e) is from [83] (Hawaii Scientific Drilling Project (HSDP) sample 4656.7). (b) and (d) are from sample DSDP-418A-68-3[40–43], and (f) is from sample DSDP-418A-75-3[120–123]. Note the similarities when comparing (a), (c), and (e) to (b), (d), and (f), respectively, despite the differences in their inferred origin (biotic versus abiotic). ARTETs: alpha-recoil track etch-tunnels; plg: plagioclase phenocryst.