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Table T3. Petrographic descriptions of thin sections from select lithified intervals to support macroscopic core descriptions, Hole M0027A.

Core, section, interval (cm) Thin section Top
Comments Section
124R-1, 46–52 1 353.92 Slide to aid core description for Unit I. Medium to coarse glauconite-bearing sandstone. Grains of quartz, feldspar, and rock fragments (granitoids) show subangular to rounded shape. Apatite and zircon are also found as accessory minerals. Glauconite pellet (green) is dominant mineral formed by authigenic diagenesis. Flocks of magnetic grains are associated along glauconite boundaries. Significantly altered calcite cement is common. 3131614 250034, 250035,
250036, 250037
125R-1, 139–143 1 355.52 Slide to aid core description for Unit I. Medium grained sandstone. Grains with subangular to subrounded shapes mostly
consist of quartz and associated feldspar (perthite, microcline, and plagioclase), rock fragments (granitoids, gneiss, and
marble), magnetic grains, zircon, and chlorite. Matrix is filled with clay and organic materials and is partly recrystallized by calcite cement.
3131615 250038, 250039,
250040, 250041
125R-1, 0–4 1 355.6 Slide to aid core description for Unit I. Medium sandstone. Grains are composed mainly of monocrystalline quartz and
subordinantly of feldspar (microcline, plagioclase, and perthite), rock fragments (granitoids, schist/gneiss, quartzite, and
marble), zircon, muscovite, authigenic glauconite, and fossils (radiolarians, shell, etc.). Some grains are coated by
microcrystalline calcite. Matrix is filled with argillaceous mud and clay, organic materials, and opaque minerals. Calcite in
matrix is partly recrystallized.
3131616 250030, 250031,
250032, 250033
127R-2, 3–7 1 361.09 Slide to aid core description for Unit I. Fine sandstone. Matrix consists of mud and silt material, unidentified clay mineral
flakes, and organic/nonorganic materials. Flakes of chlorite and sericite in matrix are commonly layered. Brown pellets
occasionally observed in matrix are considered to be oxidized glauconite formed by diagenesis. Detrital grains are quartz,
feldspar, opaque mineral, muscovite, zircon, and fossil carbonate fragments.
3131620 250042, 250043,
250044, 250045
171R-1, 38–42 1 489.77 Slide to aid core description for Unit II. Quartzose glauconite-bearing medium sandstone. Detrital grains consist mainly of
quartz and feldspar. Sediment texture is grain supported to matrix supported and rich in authigenic glauconite pellets
formed within matrix. Glauconite is aggregated by fine pellets that are pale green in grain margin and green to dark green
in grain center. Some glauconite grains are coated by oxidized iron layers. Recrystallized calcite aggregates occupy matrix
as relict minerals.
3131750 270058, 270059,
270060, 270061

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