Provenance and diagenesis of the Miocene Bear Lake Formation, Bristol Bay basin, Alaska
dc.contributor.author | Hartbauer, Cheryl Lynne | |
dc.date.accessioned | 2015-06-30T01:19:28Z | |
dc.date.available | 2015-06-30T01:19:28Z | |
dc.date.issued | 2010-08 | |
dc.identifier.uri | http://hdl.handle.net/11122/5604 | |
dc.description | Thesis (M.S.) University of Alaska Fairbanks, 2010 | en_US |
dc.description.abstract | The Miocene Bear Lake Formation (BLF) is a prospective hydrocarbon reservoir exposed on the southwestern Alaska Peninsula, extending into the subsurface to the northwest (reaching 2,360 m maximum thickness). This study comprehensively characterizes composition of BLF sandstones, and develops important implications for varying reservoir quality. Unique integration of standard petrographic methods, electron microprobe analysis (EMPA), and ⁴⁰Ar/³⁹Ar dating of detrital hornblende strengthens interpretations by providing multiple lines of evidence and a more complete picture of composition, source units and terrane, and diagenetic history than possible with petrography alone. EMPA provides superior classification of volcanic rock fragments and identification of diagenetic minerals. Results indicate a pressure-controlled diagenetic system, and a provenance more complicated than recycling of older strata, as currently interpreted. Simultaneous derivation from the Meshik Volcanics and recycling of Tolstoi, Chignik, and Naknek formations suggests erosion of a structurally-deformed source terrain (e.g. reverse-faulted anticlines). Abundance patterns of pore-filling zeolites, calcite, albite, and kaolinite likely represent variations in Pco₂ caused by variations in burial depth. Optimal reservoir quality is likely present in the subsurface upper BLF along the northwestern coast (and deeper in the basin), where sandstone composition is presumably more quartz-rich, less volcaniclastic, and has experienced higher Pco₂ fluid migration. | en_US |
dc.description.tableofcontents | 1. Introduction -- 2. Materials -- 3. Geologic background -- 3.1. Regional stratigraphy -- 3.1.1. Mesozoic -- 3.1.2. Tertiary -- 3.1.3. Bear Lake Formation -- 3.1.3.1. Recent studies of the Bear Lake Formation -- 3.2. Magmatic arcs of the Alaska Peninsula -- 3.3. Regional geologic structure -- 3.3.1. Bristol Bay Basin -- 3.3.2. Bruin Bay Fault and Ugashik Lakes Fault System -- 3.3.3. Ugashik Sub-Basin -- 3.3.4. Structure of the Herendeen Bay-Port Moller area -- 4. Petrography -- 4.1. Introduction -- 4.2. Methods -- 4.3. Results -- 4.3.1. Point Count data -- 4.3.2. Ternary diagrams -- 4.3.2.1. Quartz, feldspar, and lithic grains -- 4.3.2.2. Monocrystalline components -- 4.3.2.3. Composition of lithic grains -- 4.3.2.4. Intergranular components -- 4.3.2.5. Tectonic Provenance diagrams -- 4.4. Discussion -- 4.5. Conclusions -- 5. Electron microphobe analysis -- 5.1. Introduction -- 5.2. Methods -- 5.2.1. Analytical routine and strategy -- 5.2.2. Criteria for naming clays -- 5.2.3. Potential sources of error -- 5.3. Results -- 5.3.1. Diagenetic mineralogy -- 5.3.2. Volcanic rock fragments -- 5.3.2.1. Mineralogy and alteration -- 5.3.2.2. Composition -- 5.3.3. Detrital plagioclase clasts -- 5.4. Discussion -- 5.4.1. Evaluation of petrographic identifications of diagenetic minerals -- 5.4.2. Classification of volcanic rock fragments -- 5.4.2.1. Potential volcanic provenance -- 5.4.3. Detrital plagioclase clast provenance -- 5.5. Conclusions -- 6. Geochronology -- 6.1. Introduction -- 6.2. Methods -- 6.3. Results -- 6.4. Discussion -- 6.4.1. Potential igneous source rocks on the Alaska Peninsula -- 6.4.2. Sources of detrital Hornblende in the Upper Bear Lake Formation -- 6.4.2.1. Jurassic -- 6.4.2.2. Early cretaceous -- 6.4.2.3. Paleocene to early eocene -- 6.4.2.4. Eocene to oligocene -- 6.5. Conclusions -- 7. Provenance -- 8. Diagenesis -- 8.1. Introduction -- 8.2. Thermal maturity -- 8.3. Mineral stability -- 8.3.1. Heulandite-Laumontite-Calcite -- 8.3.2. Kaolinite-Laumontite-Calcite -- 8.4. Summary and conclusions -- 9. Summary and conclusions -- References cited -- Appendicies. | en_US |
dc.language.iso | en_US | en_US |
dc.title | Provenance and diagenesis of the Miocene Bear Lake Formation, Bristol Bay basin, Alaska | en_US |
dc.type | Thesis | en_US |
dc.identifier.department | Department of Geology and Geophysics | |
refterms.dateFOA | 2020-03-05T10:35:48Z |
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