Late Jurassic-Early Cretaceous climate change record in clay minerals of the Norwegian-Greenland Seaway

摘要

The humid climate of northwestern Europe during the Late Jurassic Early Cretaceous was punctuated by widespread arid phase. There are few well constrained and complete sections that document this climate shift from semi-humid to arid, and back to more humid conditions. Detrital clay minerals formed in soils and derived through weathering may be used as palaeoclimatic proxies, and here, clay mineral assemblages from several well-constrained sections from the Norwegian Continental Shelf are presented as a N-S transect of the Norwegian-Greenland Seaway. Palaeoclimate signals in most of the clay mineral sections are complicated by diagenetic overprinting. Yet, towards the Boreal realm of the Norwegian-Greenland Seaway there is a discernib palaeoclimatic signal in the clay mineralogy of Well 16/3-4. At similar to 30 degrees N, kaolinite is known to have reappeared in the clay mineralogical record in the upper part of Calpionellid Zone B (early-mid Berriasian). However, we find an absence of kaolinite at 40 degrees N in Well 16/3-4 from the North Sea until the late Berriasian, suggesting that initiation of the first humid phase in the Early Cretaceous Norwegian-Greenland Seaway was diachronous.