Geology Reference
In-Depth Information
time little published data have become available
with reference to its age. However, a recently
published geological map includes clues to the
age of the Mendola Dolomite (Avanzini, 2002).
Notes from the map indicate that the 'Mendola
Formation' is a platform carbonate body of late
Anisian-early Ladinian age (Avanzini, 2002).
Portions of the map's notes are paraphrased below
(translated by N. Preto, pers. comm. 2006).
The second is the peritidal member. The lower
boundary of the peritidal member is marked by a
palaeosol and sometimes associated with tepee
horizons. The upper boundary is more variable. At
Mendola Pass, strongly karstifi ed portions are
infi lled with andesitic and basaltic volcanics that
are laterally equivalent with the basinal Roen
Limestones. Additionally, a few ammonoids of the
avisianum
subzone occur at the base of the peri-
tidal member (Preto, pers. comm.). The sedimentary
environment is that of an aggrading, periodically
exposed carbonate platform.”
“Within the Mendel Dolomit, Ogilvie Gordon (1927)
recognized a lower member with dasycladacean
algae
Diplopora anullatissima
and
Physioporella
paucifoliata
corresponding to the Sarl-Dolomit, and
an upper member with
Diplopora annulata
corre-
sponding to the Schlern-Dolomit. These conclusions
were later corroborated by von Klebelsberg (1935)
and Van Hilten (1960). Further stratigraphic studies
carried out for the purpose of geological mapping
of the area distinguished two informal units within
the Mendola Formation. The fi rst is the subtidal
member, corresponding to the Upper Serla Dolomite
and Contrin Dolomite of the eastern Dolomites.
The section measured in this study belongs
to the 'peritidal member' of the Mendola
Formation, which overlaps with the Latemar
Platform interior biostratigraphy (Fig. 6). The
assemblage of dasycladacean algae extracted
from the Mendola section includes
Physoporella
leptotheca
(Cycle 7),
Diplopora annulata annu-
lata
(Cycles 7, 8 and 20) and
Gyroporella ladinica
(Cycle 20). Dasycladacean algae of the subtidal
member of the Mendola Formation, including
Latemar
stratigraphy
540
500
Fig. 6.
Stratigraphic column of the
Latemar Platform modifi ed from
Egenhoff
et al
. (1999), Preto
et al
. (2001)
and Manfrin
et al
. (2005) on the left
and proposed correlative stratigraphic
chart from Mendola Pass to the right.
Depth scale applies to both charts.
Dasycladacean algae from Latemar
section are reported in Gaetani
et al
.
(1981). LTF, Lower Tepee Facies; LCF,
Lower Cyclic Facies; MTF, Middle
Facies; UCF, Upper Cyclic Facies; UTF,
Upper Tepee Facies. Dasycladacean
algae and lithostratigraphy from
Mendola Pass are reported in Ogilvie
Gordon (1927) and Avanzini (2002).
Dasycladacean algae marked with an
asterisk (
P. leptotheca, D. annulata,
and
G. ladinica
) were collected at the
Mendola study interval, indicating
placement in the 'Peritidal Member'
of the Mendel Dolomit and providing
a zone of possible correlation to the
Latemar Platform based on the occur-
rence of
P. leptotheca, D. annulata
there. Correlation of Mendola study
interval to Latemar section (marked by
horizontal grey bar) is based on dasycla-
dacean biostratigraphy and maximum
statistical correlation of Mendola and
Latemar cycle thickness series.
450
Mendola Pass
correlation
400
350
Position of study
interval based on
Dasycladacean
and maximum
statistical correlation
300
250
200
xx
x
x
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150
100
50
0
