Figure 2 | Scientific Reports

Figure 2

From: Glaucony authigenesis, maturity and alteration in the Weddell Sea: An indicator of paleoenvironmental conditions before the onset of Antarctic glaciation

Figure 2

Glauconitic packstone facies. (A,B) Plain-polarized light (PPL) photomicrographs of glaucony grains of types 1, 2 and 3. (C) PPL photomicrograph of a glauconitized mineral (mica)-grain (yellow arrow). (D) SEM photomicrograph (BSE) showing the spotty flaky texture in section of a type 1 glaucony grain (white arrow) and the smooth interior of type 3 glaucony (yellow arrow). Note cracks and poorly altered rims associated with type 3 glaucony. (E,F) SEM photomicrographs (SE) showing the nanostructure of the surface of type 1 glaucony, with probable bacterial threads (ill-defined globules/caterpillar structures; yellow arrow) and coccoid-like forms (white arrows). (G) Energy-dispersive X-ray (EDX) analysis of type 1 glaucony. (H) SEM photomicrographs (SE) showing the development of type 1 glaucony nanostructure from ill-defined globules/caterpillar to low packing size/density lamellar-flaky. (I) SEM photomicrograph (SE) showing type 2 glaucony nanostructure with well developed evolved flaky honeycombed-shaped structures. (J) HRTEM image showing well-defined ~10Å lattice fringes of glauconite crystal and related interstratified smectitic area.

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