Chaîne varisque
Open Access

Table 3

Zircon external and internal morphology. Indexing after Caruba and Turco (1971) for prismatic (100 and 110) and pyramidal faces (211 and 101).

Sample Extracted zircon (μg/g) Whole-rock Zr content (μg/g) Zircon grains Zircon sections
Vo14-16 159 153 Clear, euhedral, 100 < 110 et 211>101 Concentrically zoned in CL
Vo15-01 <607 315 Short, multi-facetted soccerballs, cracked by internal inflation; highly metamict, creamy pattern under direct light (binocular); almost opaque, dark brown in transmitted light KF, biot, thorite, apatite inclusions, very dark in CL
Vo15-04 230 223 Pale pink and milky but transparent; often irregularly, step-facetted, or as easily broken arrowheads; looking corroded and/or fast crystallized Dark in CL
Vo15-07 261 448 Mostly elongate needles, clear, euhedral, 100>110 up to 100 alone, 101>211 up to 101 alone Dark in CL, biotite inclusions, axial (glassy?) inclusions in elongate sections
Vo15-08 191 131 Colourless, clear, many broken needles, plus shorter well-terminated euhedral grains, 100>110 and 101>211 Axial (glassy?) inclusions in elongate sections, concentrical zoning in CL for shorter sections

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