Fróðskaparrit - 01.01.1998, Side 201

HÁLENDISVINDBORIN SETLØG f FØROYUM
207
lian deposits has been briefly mentioned
(Humlum and Christiansen, in press) to
form part of the periglacial landforms of
the Faroe Islands.
In the following a short description of the
present knowledge of the morphology, lo-
cation, sedimentology and age of the
Faroese highland aeolian sheets is given.
Some indications as to the future use of
these deposits in reconstructing palaeo-
wind directions and periods of activity are
implied.
Morphology and location
of aeolian deposits
The aeolian deposits occur in more or less
undulating sheets and have smooth contin-
uous surfaces devoid of boulders and cob-
bles. There is thus a significant visual dif-
ference between the diamict covered hill-
slopes or bedrock outcrops that dominate
the surface of the Faroese highlands and the
aeolian deposits. Another characteristic of
the aeolian sheets is that they are complete-
ly covered only by grass vegetation, op-
posed to the more mixed vegetation of the
rest of the landscape. This gives the wind-
blown deposits a very homogeneous ap-
pearance in a landscape otherwise dominat-
ed by an uneven surface with boulders and
bedrock protruding in several areas. It also
shows that these aeolian deposits to some
degree can have accumulated during for-
mer more extensive periods of wind activi-
ty than at the present.
Aeolian sediments are often deposited
immediately downslope pass areas, such as
at Neytaskarð north of Norðradalur on
Streymoy. They are also accumulating
above free faces that reach almost vertical-
ly down to sea level, such as at Eiðiskollur
on Eysturoy (Fig. 1) or are associated with
inland free faces or mountain slopes as at
Tindur SE of Vestmanna on Streymoy (Fig.
2). Finally some have simply accumulated
on gently sloping mountain sides; an exam-
ple is seen south of Høgareyn, south of
Vestmanna. Primarily, the inland aeolian
deposits are located on southfacing slopes,
but the deposits associated with free faces
reaching sea level can occur on slopes with
all directions and even on almost horizontal
mountain top surfaces. Aeolian deposits
occur both below, but mainly above the
modern lower limit for periglacial activity
at the Faroe Islands at about 250 - 450 m
a.s.l. as determined by Humlum and Chris-
tiansen (1998; in press).
The aeolian deposits located above free
faces reaching sea level are presumably the
largest. They tend to occur at free faces that
have a northerly or westerly exposure, and
seem to be thickest closest to the free face
top, becoming thinner away from it. At the
small peninsula Slættanes on Vágar a iarge
continuous aeolian cover is deposited im-
mediately above a free face only about 150
m high, with a northwesterly aspect. This
locality shows very clearly that aeolian
sediment accumulation must primarily
have taken place during storms from the
north, as there is no other sediment source
area than the coastal free face which is large
enough to yield such a sediment cover.
The aeolian covers associated with in-
land free faces also seem to be associated
with dominating northerly wind directions.
An example is the cover of aeolian sedi-