Figure F14. Composite graphic log illustrating characteristic structures of pahoehoe sheet lobes. The left side of the column shows the characteristic three-part division of (A) sheet lobes (CRZ = crustal zone, PLZ = platy zone, CLZ = columnar zone) and (B) jointing styles. The right side of the column shows distribution of (C) vesiculation structures (VZ = vesicular zone, MV = megavesicle, HVS = horizontal vesicle sheet, VC = vesicle cylinder, SV = segregation vesicle, PV = pipe vesicle, BVZ = basal vesicular zone), (D) vesiculation (non- to sparsely vesicular [d = 0-5 vol%], moderately vesicular [m = 10-20 vol%], and vesicular [v = 30-40 vol%]), and (E) degree of crystallinity (G = hyaline, hyh = hypohyaline, hc = hypocrystalline, c = holocrystalline). The scale h/l indicates normalized height above the base of the sheet lobe (h = height in lobe and l = total lobe thickness) (from Thordarson and Self, 1998).