id	author	title	date	pages	extension	mime	words	sentence	flesch	summary	cache	txt
geusb-4903	Gravesen, Peter; Roll Jakobsen, Peter	Pre-Quaternary rocks and sediments with a high level of radioactivity in Denmark	2016	4	.pdf	application/pdf	2733	140	61	but the high value for the radon emana- tion of the black clay can only be compared with levels of Paleocene black clay from the Erslev area which has even higher values (Table 1). In a few shallow boreholes at Thisted, more than 50 cm of black clay has been encountered indicating non-eroded remnants of the black clay, and black clay material is also enclosed in the till at some locations.	cache/geusb-4903.pdf	txt/geusb-4903.txt