| mhorn | Дата: Tuesday, 20.04.2010, 20:11 | Сообщение # 1 |
Admin
Group: Администраторы
Posts: 1060
Reputation: 0
Status: Offline
| Branski P. (2010) Kaolinite peaks in early Toarcian profiles from the Polish Basin – an inferred record of global warming // Geol. Quart., 54 (1): 15–24. Warszawa.
pdf: http://www.pgi.gov.pl/images/stories/G_Q/54_1/branski.pdf
In lower Toarcian clay deposits (Ciechocinek Fm., VIII depositional sequence of the Lower Jurassic) from three boreholes from the Polish Basin, illite-dominated sedimentation representing the lower part of studied interval was in terrupted by enhanced kaolinite input. Levels of high kaolinite/illite ratio at the VIIIb/VIIIc parasequence boundary suggest strong continental weathering in a humid-subtropical to tropical climate related to the phase of the early Toarcian global warming recorded at the top of the tenuicostatum Zone and correlated with isotope curves from a number of European sections. Kaolinite enrichment may be locally enhanced by reworking of pre-Jurassic kaolinitic rocks and differential settling. Diagenetic processes were not sufficient enough to trans form the initial kaolinite, but may have altered smectite and mixed-layers into illite and/or chlorite.
Middle Jurassic - Lower Cretaceous ammonites & aptychi
|
| |
| |
