The vertical and lateral aggradation of terminal and crevasse splay deposits in continental environments can form extensive fine-grained, sheet-like sandstone bodies which may form an important but often overlooked component of subsurface hydrocarbon reservoirs. This study examines splay deposits on the modern day Distributive Fluvial System (DFS), of the Parapeti River, Bolivia, using remote sensing techniques and geographic information system (ArcGIS) to characterise both lateral and terminal modern splay systems. Overall emphasis is given to the spatial and temporal relationship between sedimentary facies at the distal part of the Parapeti DFS over the past 42 years. A sedimentary facies evolution model is created to account for the development of the distal part of the Parapeti DFS. A number of splay deposits have formed and developed during this period and the Parapeti channel has prograded ~17 km basinward by short-term deposition in one location, followed by either repeated local avulsion or coeval downstream progradation of the terminal channel and associated splays. Rock record examples from the Miocene aged Huesca DFS in the Ebro Basin, Spain were studied in order to compare dimensional data as well as understand the relationship between splays and associated channel bodies. The study area is characterized by thin sandstone sheets (0.05-2.6 m thick; 100s m wide) interbedded with mudstones and siltstones interpreted to represent a terminal splay complex based on the distribution of facies, architectural elements and paleocurrent data. There is a strong resemblance between the model developed for the Parapeti DFS and the splay complexes recorded in the Miocene Huesca DFS. Sedimentary models are proposed in which terminal splay formation through avulsions is considered to be the dominant process in the distal parts of both systems. Avulsions control sediment distribution, resulting in stacking of splay deposits to form extensive sandstone sheets. However, it is suggested that different types of avulsion successions (i.e. progressive or abrupt) recognized by previous workers, may not be distinguishable in the rock record as they can produce a similar stratigraphic signature.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:693267 |
| Date | January 2016 |
| Creators | Do, Thi Thuy Linh |
| Publisher | University of Aberdeen |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=230525 |
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