Acta naturalia Islandica - 01.02.1946, Side 14

Acta naturalia Islandica - 01.02.1946, Side 14
8 TRAUSTI EINARSSON a proof of the Quaternary age of the Hreppar rocks. This appar- ent inconsistency does, however, not appear in the final formu- lation of Pjeturss’ views in 1910, where every moraine is considered of Quaternary age.7) In 1905, however, Pjeturss thought it obvious that the Fnjóskadalur moraines are older than the Pliocene of Tjör- nes and it does not appear that it has been shown directly that the relation is the reverse. L. Hawkes thinks it quite obvious that the Fnjóskadalur sediments are older than the Pliocene of Tjörnes.8) But Hawkes denies the exis- tence of moraines at Fnjóskadalur where reported by Pjeturss. On the other hand J. Líndal reports that he has found a number of moraines in the mountains in question.9) The existence of moraines in these localities seems thus to be somewhat doubtful. But what about the age of these sediments? If they are older than the Pliocene of Tjörnes and are genuine mora- ines, then Pjeturss’ time-scale is entirely upset and we have got a Tertiary glaciation of Iceland. But Pjeturss system as a whole appears to be so well-founded that it cannot be upset by this. The obvious answer to the difficulty just mentioned would be that the moraines at Fnjóskadalur, if genuine, must be younger than the Pliocene of Tjörnes. Some geologists, however, believe that the Pliocene is younger than the “moraines” and this is therefore still an open question. But it seems a priori improbable that the answer to it can seriously influence Pjeturss’ system as a whole. An apparent weakness of the system, which L. Hawkes has already pointed out is the tremendous work of modelling the fjord land- scape of Northern and Western Iceland which according to the system was carried out during part of the Quaternary period. But this is perhaps no real weakness. According to Pjeturss there is no escape from the conclusion that an enormous erosion was carried out in Quaternary times, and this seems to be in accordance with the view of some Norwegian geologists that the Norwegian fjords are of Quaternary, even Middle or Late Quaternary age. Pjeturss’ main arguments, obtained in Snæfellsnes, are, it must be admitted, very strong and seemingly also those derived from the moraines at Hval- fjörður, where a striated floor of the moraines is also reported. — I have in the foregoing pointed out some difficulties which arise in connexion with Pjeturss’ system, but they all seem to be of no

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Acta naturalia Islandica

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