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 12. The relationship between clay fraction (<2 μm) and clay mineral abundance with mean grain size, colored as a function of depositional environment. (A) Clay fraction, (B) chlorite, (C) illite, and (D) kaolinite. Note that coarser-grained outer-estuarine sediment has a paucity of clay-size material (<0.5%). Illite, chlorite, and kaolinite abundance increase with a decrease in mean grain size (i.e., in mud flats and mixed flats). Chlorite lithics (see Figure 6B) are likely to explain elevated chlorite abundance in tidal dunes and bars despite relatively low clay fraction content. 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 12. The relationship between clay fraction (<2 μm) and clay mineral abundance with mean grain size, colored as a function of depositional environment. (A) Clay fraction, (B) chlorite, (C) illite, and (D) kaolinite. Note that coarser-grained outer-estuarine sediment has a paucity of clay-size material (<0.5%). Illite, chlorite, and kaolinite abundance increase with a decrease in mean grain size (i.e., in mud flats and mixed flats). Chlorite lithics (see Figure 6B) are likely to explain elevated chlorite abundance in tidal dunes and bars despite relatively low clay fraction content. 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).