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 depth (mbsf) |
Comments |
Section ID |
Photo |
|---|---|---|---|---|---|
| 313-M0027A- | |||||
| 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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