Seasonal record from recent fluvial tufa deposits (Monasterio de Piedra, NE Spain): sedimentological and stable isotope data - Tufas and Speleothems: Unravelling the Microbial and Physical Controls - page 126

Cross-sections of tufa deposited on tablets:
identification of six-monthly intervals

events; and (2) presence or absence of lamination
and/or textural variations.

Sedimentary record from tablets in fast
flowing water areas

The identification of the different sedimentation
intervals (i.e. the periodic thickness variations
obtained with the MEM) was made by plotting on
each tablet section the successive thickness data
measured every six months with the MEM that cor-
responded to the five-point row that coincided with
the cross-section cutting (Fig. 4). The recognition of
the different sedimentation intervals presented a
number of problems depending on: (1) thickness of
the preserved deposits, in some cases closely
related to the intensity and/or frequency of erosion

In general, the laminated record of tablets in fast
flowing conditions had a rather good correlation
with the several thickness data obtained seasonally
with the MEM (Figs 4a & 5b, d, f). The smoothly
domed morphology typical of this laminated
facies caused some lack of coincidence between
the five-point lines obtained with the MEM and
the intervals recognized on the tablet sections.

Fig. 4. Cross-sections of (a) tablets 3 (fast flow conditions on the river bed) and (b) 7 (stepped waterfall) and thickness
of each cool and warm period. For each case, white lines joint the thickness data measured seasonally with the
MEM at the five points of the row closest to the tablet cross-section cutting. In (b), numbers help see the succesive
seasonal measures; dashed lines represent erosion, deduced as negative values of thickness (e.g. lines 4 and 8)
with respect to the previous measures (e.g. lines 3 and 7).