The AAPG/Datapages Combined Publications Database
AAPG Bulletin
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AAPG Bulletin; Year: 2019; Issue: April DOI: 10.1306/09181818025
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Figure 13. The relationship between (A) illite chemistry (Esquevin index) and (B) illite crystallinity (full width at half maximum of the 10 Å peak) and mean grain size. Note that illite crystallinity and illite Fe–Mg content is reduced with an increase in mean grain size (i.e., in outer-estuarine sediment). Depositional environments are labeled accordingly: gravel bed (De1); mud flat (De2); mixed flat (De3); sand flat (De4); tidal bars and dunes (De5); tidal inlet (De6); backshore (De7); foreshore (De8); and proebb delta (De9). Mean grain-size classes are labeled accordingly: silt; lower very fine sand (vfL); upper very fine sand (vfU); lower fine sand (fL); upper fine sand (fU); lower medium sand (mL); upper medium sand (mU); and lower coarse sand (cL).
Figure 13. The relationship between (A) illite chemistry (Esquevin index) and (B) illite crystallinity (full width at half maximum of the 10 Å peak) and mean grain size. Note that illite crystallinity and illite Fe–Mg content is reduced with an increase in mean grain size (i.e., in outer-estuarine sediment). Depositional environments are labeled accordingly: gravel bed (De1); mud flat (De2); mixed flat (De3); sand flat (De4); tidal bars and dunes (De5); tidal inlet (De6); backshore (De7); foreshore (De8); and proebb delta (De9). Mean grain-size classes are labeled accordingly: silt; lower very fine sand (vfL); upper very fine sand (vfU); lower fine sand (fL); upper fine sand (fU); lower medium sand (mL); upper medium sand (mU); and lower coarse sand (cL).