RT Journal Article
T1 Depositional setting and early diagenesis of the dinosaureggshell-bearing Aren Fm at Bastus, Late Campanian,south-central Pyrenees
A1 Díaz Molina, Margarita
A1 Kälin, Otto
A1 Benito Moreno, María Isabel
A1 López Martínez, María Nieves
A1 Vicens, Enric
AB The Late Cretaceous Aren Fm exposed north of Bastus in the Tremp Basin (south-central Pyrenees) preserves an excellent record of dinosaur eggs laid in a marine littoral setting. Different from other cases reported in literature, at the Bastus site the preferential nesting ground was original beach sand. The coastal deposits of Aren Fm can be grouped into four facies assemblages, representing respectively shoreface, beachface, beach ridge plain and backbarrier lagoon environments. Shoreface deposits include fine- to coarsegrained hybrid arenites and subordinate quartz-dominated conglomerates with ripple structures of wave and wave-current origin.Beachface deposits are mainly storm beach conglomerates, but parallel-laminated foreshore arenites locally occur. Backbarrier lagoon deposits comprise of washover sandy conglomerates that grade laterally into sandy lime mudstones, biomicrites and marls.Beach ridge sediment, wherein the bulk of dinosaur eggs and eggshell debris occurs, predominantly is a reddish hybrid arenite that has undergone a complex early diagenetic evolution, including marine and meteoric cementation followed by soil development. The reddish arenites overlie wave-dominated shoreface deposits and in places pass laterally into lagoonal deposits.They originally formed shore ridges, that became stabilized during progradational episodes by pedogenesis (beach ridge, sensu[Otvos, E.G., 2000. Beach ridges—definitions and significance. Geomorphology 32, 83–108.]), which also affected the dinosaur eggs. The eggshell-bearing beach ridge arenites are typically preserved at the top of parasequences forming the systems tracts of a third-order sequence. Thick packages of this facies resulted from aggradation of barrier/beach ridge deposits, whose preservation below surfaces of transgressive erosion was favoured by incipient lithification.
PB Elsevier
SN 0037-0738
YR 2007
FD 2007-07-15
LK https://hdl.handle.net/20.500.14352/50446
UL https://hdl.handle.net/20.500.14352/50446
LA eng
DS Docta Complutense
RD 26 ago 2024