Origin and internal architecture of an offshore mudstone belt

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Mudrocks are relatively understudied and are mostly ignored despite the fact that they comprise over 50 % of all sedimentary rocks in the geologic record. There has been a renewed interest in mudrocks over the past few years partly in response to the economic potential of shale gas and basin center gas. The focus of this research will be the Cretaceous Mancos Shale mudstone belt in Utah. The Cretaceous was a naturally occurring greenhouse period in Earth's history when the dinosaurs reigned supreme and the Western Interior of North America from Arctic Canada to the Gulf of Mexico was flooded with sea water. Global sea level was up to 250 m higher than present day. The Cretaceous Western Interior Seaway (CWIS) dissected the North American continent into two parts: a mountainous western half and a lower-lying eastern half. The western half was tectonically active with only a narrow coastal plain separating the mountains from the sea. Small- to moderate-sized, fast-flowing rivers drained the eastern part of the mountains and transported a significant volume of sediments into the CWIS, depositing a thick succession of sands, silts and clays. Following deposition and lithification, these sedimentary rocks were slowly uplifted to form the magnificent scenery in the western interior of the United States. One of the most spectacular regions is the Canyonlands-area of east-central Utah which is home to one of the longest continuous cliff-lines in the world, the 300-km-long Book Cliffs. The main objective of this research is to add fundamental new knowledge regarding the origin and internal architecture of offshore mudstone belts. Long-term goals for this research are to unravel the sediment delivery mechanisms and dominant direction of sediment transport on the shelf, and to develop appropriate models for shelf mudstones. Unravelling the origin and internal architecture of the Mancos Shale mud belt will lead to a better understanding of shallow marine sedimentation patterns, sea level change (i.e. rate, magnitude, cyclicity), basin history and environmental change through time. The latter is essential for placing our modern "early stage" greenhouse conditions into their proper historical perspective.