SEDIMENTOLOGICAL CHANGES ACROSS THE ORDOVICIAN-SILURIAN BOUNDARY IN HADELAND AND THEIR IMPLICATIONS FOR REGIONAL PATTERNS OF DEPOSITION IN THE OSLO REGION - A REPLY
Cjr. Braithwaite et al., SEDIMENTOLOGICAL CHANGES ACROSS THE ORDOVICIAN-SILURIAN BOUNDARY IN HADELAND AND THEIR IMPLICATIONS FOR REGIONAL PATTERNS OF DEPOSITION IN THE OSLO REGION - A REPLY, Norsk geologisk tidsskrift, 76(4), 1996, pp. 257-258
Baarli (this issue. pp. 253-255) provides general support For our mode
l of an easterly supply of sediment into the Oslo Region during the la
test Ordovician and Rhuddanian. Our block model for the basin is neces
sarily schematic but, importantly, shows a series of half-grabens with
their basement surfaces tilted eastwards. The interplay between fault
movement and rate of sediment supply was thus able to produce sea flo
or topographies which differed from half-graben to half-graben and cou
ld show Local eastward deepening, but with the overall transport of si
liciclastic material into the basin from the east. However, Baarli als
o provides new and convincing evidence for the derivation of sediment
of a new provenance, from the west, during the Aeronian. Our basin mod
el can accommodate this with the continuation of an eastern source and
westward dipping palaeoslope in the Hadeland segment of the basin.