Three new Cenomanian-Coniacian cores from the Ruhrgebiet (northwestern Germany) provide the opportunity to study the otherwise poorly exposed proximal zone of the southwestern MÃ¼nsterland Cretaceous Basin. The strata formed in an epicontinental shallow-marine environment and are assigned to four lithostratigraphical units, i.e., the Essen GrÃ¼nsand Formation, BÃ¼ren Formation, Duisburg Formation and Emscher Formation. The cores have been logged and described in detail with respect to litho- and biofacies, dated using an integrated approach and sampled for microfacies analysis. The litho- and biofacies analyses as well as the microscopic study of thin sections resulted in the differentiation of three principle facies associations (FA): transgression conglomerates (FA I), sandstones rich in glauconies (FA II) and spiculitic, silty-sandy marls (FA III). These can be associated with the depositional environment of an inner shelf (FA I-II) and a proximal middle shelf (FA III). The facies associations contain characteristic components and fabrics, resulting in the differentiation of nine facies types (FT). Five principal sediment sources are evident: (1) siliciclastics shed from the south (Rhenish Massif), (2) skeletal grains of calcareous macrobenthic organisms, (3) planktic carbonate (c-dinocysts, planktic foraminifera, nannofossils), (4) biogenic silica (mainly from siliceous sponges), and (5) authigenic glaucony grains. The integrated facies analysis leads to a much better understanding of depositional environments and sedimentary dynamics at the southern margin of the Late Cretaceous epicontinental sea in northwest Germany.
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|Titolo:||Facies analysis of proximal Upper Cretaceous deposits from the southwestern MÃ¼nsterland Cretaceous Basin (northwest Germany)|
|Data di pubblicazione:||2017|
|Appare nelle tipologie:||03.1 Articolo su rivista|