Show simple item record

dc.contributor.advisor Marsaglia, Kathleen M en Nolasco, Jasmyn en 2016-02-02T21:01:35Z en 2016-02-02T21:01:35Z en 2015 en 2/2/2016 en 2015-12 en
dc.identifier.uri en
dc.description California State University, Northridge. Department of Geological Sciences. en
dc.description.abstract The modern east-flowing Amazon River system is geologically recent, resulting from a major drainage reorganization in the Miocene to Pliocene. Different depositional environments (fluvial/ deltaic/ lacustrine/ tidal-marine) have been proposed for the Andean foreland just prior to the drainage reorganization as recorded in the Madre de Dios Formation exposed in the upper reaches of the Amazon River catchment. The objective of this study is to constrain the stratigraphy, depositional environment and drainage evolution in southern Amazonia through petrographic analysis and provenance of the sand and mud fractions of the three recognized members of the Madre de Dios Formation. Samples were examined from three stratigraphic sections measured previously along riverbank outcrops: Cerro Colorado, Piedras River and Candelaria. Petrographic analyses of 144 smear slides made from muddy samples show the major silt components to be quartz, feldspar and mica, with no identifiable microfossil or pyroclastic debris. Petrographic analyses of thin sections of sand separates from 25 sandy samples show that the sand components include abundant monomineralic (Qm) and polymineralic (Qp) quartz. Sedimentary (Lsa and Lsi) and metamorphic (Lmp, Lmt, Lmf) lithic fragments are common to abundant. Muscovite, potassium feldspar and sodium-plagioclase are less abundant. All of the sand samples are lithic arenite in composition with a recycled orogen provenance. Mineralogical maturity increases up-section, but slightly higher feldspar in member B is likely a function of a change in source area or depositional environment. Sand composition in member C is similar to the modern river sand composition, consistent with the recycling of Madres de Dios Formation sand into the modern river system. There are six main colors of mud in the Madre de Dios Formation and these characterize distinct stratigraphic intervals from I at the base to VI at the top of each section that do not correspond directly to member boundaries. There are no significant changes in mud composition among the three members. Red to orange to brown mudstones, like those that dominate Madre de Dios Formation members A and C, are formed in oxidizing environments generally in continental settings (e.g., fluvial systems). None of the 144 smear slides or the 25 thin sections contained microfossils, and the lack of marine or marginal marine biogenic debris appears to rule out tidal influence for member B. Based on its light olive gray color, interval (IV) in member B may have been deposited in a more reducing environment such as a lacustrine-deltaic setting. Overall, the Madre de Dios Formation exhibits up-section compositional and thickness trends that are indicative of changes in provenance and depositional environment from fluvial (member A) to lacustrine/deltaic (member B) to fluvial (member C). en
dc.description.statementofresponsibility by Jasmyn Nolasco en
dc.format application/pdf en
dc.format.extent ix, 72 pages en
dc.language.iso en en
dc.publisher California State University, Northridge en
dc.rights.uri en
dc.subject Lithostratigraphy en
dc.subject Drainage Development en
dc.subject Madre de Dios Basin en
dc.subject Madre de Dios Formation en
dc.subject Neogene en
dc.subject Depositional Environment en
dc.subject Provenance en
dc.subject Petrography en
dc.subject Stratigraphy en
dc.subject Amazon Basin en
dc.subject.other Dissertations, Academic -- CSUN -- Geology. en
dc.title Use of Sedimentary Petrology and Provenance to Resolve Questions Regarding Neogene Fluvial/Lacustrine Drainage Development and Potential Marine Influence in the Southern Rim of the Amazon Basin en
dc.type Thesis en 2016-02-02T21:01:35Z en
dc.contributor.department Geological Sciences en M.S. en
dc.contributor.committeemember Hertel, Fritz S en
dc.contributor.committeemember Heermance, Richard V en
dc.contributor.committeemember Campbell, Kenneth en
dc.rights.license By signing and submitting this license, you the author grant permission to CSUN Graduate Studies to submit your thesis or dissertation, and any additional associated files you provide, to CSUN ScholarWorks, the institutional repository of the California State University, Northridge, on your behalf. You grant to CSUN ScholarWorks the non-exclusive right to reproduce and/or distribute your submission worldwide in electronic or any medium for non-commercial, academic purposes. You agree that CSUN ScholarWorks may, without changing the content, translate the submission to any medium or format, as well as keep more than one copy, for the purposes of security, backup and preservation. You represent that the submission is your original work, and that you have the right to grant the rights contained in this license. You also represent that your submission does not, to the best of your knowledge, infringe upon anyone's copyright. If the submission contains material for which you do not hold copyright, or for which the intended use is not permitted, or which does not reasonably fall under the guidelines of fair use, you represent that you have obtained the unrestricted permission of the copyright owner to grant CSUN ScholarWorks the rights required by this license, and that such third-party owned material is clearly identified and acknowledged within the text or content of the submission. If the submission is based upon work that has been sponsored or supported by an agency or organization other than the California State University, Northridge, you represent that you have fulfilled any right of review or other obligations required by such contract or agreement. CSUN ScholarWorks will clearly identify your name(s) as the author(s) or owner(s) of the submission, and will not make any alterations, other than those allowed by this license, to your submission. en

Files in this item


This item appears in the following Collection(s)

Show simple item record

Search DSpace

My Account

RSS Feeds