Sunday, 25.06.2017
Jurassic Forum



[ New messages · Members · Forum rules · Search · RSS ]
Page 1 of 11
Jurassic Forum » JURASSIC references & paper reviews » Jurassic around the world » Arp G. (2010) (Ammonitenfauna und Stratigraphie des Toarcium)
Arp G. (2010)
mhornДата: Saturday, 25.12.2010, 11:44 | Сообщение # 1
Admin
Group: Администраторы
Posts: 1060
Reputation: 0
Status: Offline
Arp G. (2010) Ammonitenfauna und Stratigraphie des Grenzbereichs Jurensismergel/Opalinuston-Formation bei Neumarkt i.d. Opf. (oberstes Toarcium, Fränkische Alb) // Zitteliana, Vol. A 50: pp. 25-54.

pdf: http://epub.ub.uni-muenchen.de/11987/1/zitteliana_2010_50_04.pdf

A temporary exposure at Pölling west of Neumarkt i.d.Opf. exhibited 1,7 m blue–grey marlstones of the Jurensismergel–Formation and almost 2,0 m blue–grey marly claystones of the Opalinuston–Formation with numerous ammonites, belemnites and small–sized macrobenthos. The ammonites show the well–known development from evolute, radially–ripped Dumortieria with faint keel, to Cotteswoldia with ogival whorl section, and finally relatively involute Pleydellia with lanceolate whorl section, fine–undulating ripps and sharp keel. The investigated sedimentary section shows, if compared to localities nearby, comparatively thick “Radiosus–beds” (higher Levesquei–Zone) in phosphoritic facies, with a “Striatulo–Costatus–horizon” at its basis. Above that, comparatively thick “Hircinus–beds” (Mactra and Aalensis subzones) in pyritic facies follow, overlain by at least 200 cm thick “Torulosum–beds” in phosphoritic facies. Sedimentary discontinuities are evident at the basis of the Mactra subzone, at the basis of the Aalensis subzone, and at the basis of the Torulosum subzone. A hypothetic explanation for the observed lateral thickness variations of single zones and subzones within the Jurensismergel Formation in the area of investigation is found in submarine, possibly multiple, erosional events due to intensity changes of coastline–parallel bottom currents, independent from a slow eustatic sealevel–fall.


Middle Jurassic - Lower Cretaceous ammonites & aptychi
 
Jurassic Forum » JURASSIC references & paper reviews » Jurassic around the world » Arp G. (2010) (Ammonitenfauna und Stratigraphie des Toarcium)
Page 1 of 11
Search:

jurassic.ru © 2017
Free web hostinguCoz