Timing of diagenesis and very low‐grade metamorphism in the eastern sector of the Sierra de Cameros (Iberian Range,Spain): a U–Pb SHRIMP study on monazite |
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| Authors: | P. Del Río L. Barbero P. Mata C. M. Fanning |
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| Affiliation: | 1. Dpto. Ciencias de la Tierra, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz, 11051, Puerto Real, Cadiz, Spain;2. Research School of Earth Sciences, Australian National University, Canberra ACT 0200, Australia |
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| Abstract: | The Sierra de Cameros is an intracontinental orogen and represents the north‐western part of the Iberian Range in Northern Spain. It comprises a thick sequence of syn‐rift continental sediments (mainly sandstones and carbonates) deposited during lower Cretaceous times. A unique characteristic of the Sierra de Cameros in relation to the rest of the Iberian Range is the presence of low‐grade metamorphism in certain parts of the basin, an event that predates basin inversion. This paper describes the presence, textural relationships and geochemical aspects of authigenic and/or metamorphic monazite within different lithologies from the deepest parts of the basin. Sensitive high resolution ion microprobe (SHRIMP) U–Pb dating of monazite records the presence of two age populations: the first with 206Pb/238U ages ranging from 122 to 116 Ma which is considered as diagenetic in origin, whilst the second is dated at 99 ± 2 Ma and postdates the metamorphic climax. |
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