Table 1 Methods used to investigate deposits of spring-associated limestones (SAL) of the Eastern Alps (EA). Abbreviations: AAS=Atomic
absorption spectrometry; ICP=Inductive coupled plasma spectrometry.
Method
Description
Approach
Techniques
Map compilation
No. of maps 1/50.000: 130
No. of maps 1/25.000: 36
No. of maps 1/10.000: one
No. of maps 1/75.000: one
No. of maps 1/500.000: two
Compilation of SAL deposits
indicated in geological maps on
scales of 10/000–1/500.000
Check of climatic significance of
EA-SAL deposits
Comparison of compiled SAL
deposits with (a) mean annual
temperature, (b) mean temperature
range January/July
Source of compiled maps: (a) All
maps (including Geofast maps and
'Gebietskarten') published by
Geological Survey of Austria, (b)
15 maps in 1/25.000 published by
Bayerisches Geologisches
Landesamt (Germany), (c) one
unpublished map produced by the
Brenner Basistunnel Project
Group.
Logged altitudes of SAL deposits
were compared with (a) mean
annual temperature in the EA, (b)
mean temperature range
January/July in the Tyrol, in
defined altitude increments of 500
meters or 1000 meters.
Mean annual temperature was
taken from Steinhauser & Nowak
Main goals
(1) Determine large-scale
geological controls over formation
of limestone-depositing springs
and SAL deposits,
(2) Note characteristics of SAL
deposits:
number per map sheet, altitude
range of deposits, geological
substrate, immediate substrate,
deposit size, hillslope exposition,
inferred type of SAL deposystem,
activity status, remarks
Check for presence of SAL versus
mean annual temperature and
mean temperature gauge
Remarks
Map compilation was
supplemented by own field data
With one exception, only postworld war 2 maps were used
wherein spring-limestone deposits
are mapped
–
Field documentation
Field investigation, mapping of
SAL deposits, check of entire SAL
deposystem at each location,
sampling of facies types (thin
sections)
Experimental precipitation
substrates
Placement of diverse substrates for
calcium-carbonate precipitation in
active limestone-depositing creeks
(1963), mean temperature ranges
January/July from Fliri (1980)
Deposits mapped on a scale of
1/2.000 on isohypsed satellite
orthophotographs, and/or on
laserscanned topography 1/2.000
Natural substrates:
Formatted pieces of wood,
brushes of natural fibers, loofah
'sponges', stones
Artificial substrates:
Cu-platelets, steel nails, rinse
fleece of plastic fibres, steel-fibre
meshworks
X-ray diffraction
Standard X-ray diffraction
Diffraction patterns of powdered
mineral samples of SAL deposits
X-ray with parallel-beam optics
Microbiological investigation
Samples taken in vivo in the field,
transported to lab in ambient water
in a coolbox
Investigation of entire sample and
(1) determine the extent of fossil,
inactive, and active SAL deposits
per occurrence,
(2) map areal extent of different
facies types
(1) Determine rates of
precipitation on different nonliving substrates,
(2) determine 'calcification
successions' within/on porous
substrates (rinse fleece, loofah)
(3) determine seasonality of
precipitation rate and biotic
assemblages
(1) Determine bulk mineralogy
and carbonate polymorphism,
(2) determine relative proportion
aragonite/calcite,
(3) determine Mg content in
magnesian calcite (parallel-beam
optics)
(a) Taxonomic composition of
microbiota,
(b) identification of early-formed
calcium-carbonate crystallisates
Total of 33 deposits was
checked in the field.
Not all were field-mapped (mainly
in case of small size)
Six locations spiked with
experimental substrates
Maximum total observation
interval for experimental
substrates: five years (since 2003)
Check intervals: few weeks to
more than a year (depending on
location and duration of total
observation interval)
Iron oxides presently formed
by microbes at a few active
limestone springs
are amorphous in parallel-beam Xray
Taxa of macro-algae and mosses
were mainly identified in the field,
but samples were also taken for
closer inspection in the lab
Electron microscopy
SEM (backscattered-electron
microscopy)
TEM (transmission electron
microscopy)
CP-SEM microscopy
(CP: critical-point dehydration of
microbes)
of cut-off sub-samples (some subsamples stained with methylene
blue) under
(a) reflected light,
(b) transmitted light,
(c) polarized light,
(d) dark-field microscopy
Abiotic and dead samples of
actively-forming limestone
investigated by electron
microscopy
SEM: (a) investigation of dried
and sputtered samples formerly
populated by living microbial
assemblages, (b) investigation of
samples cleared with H2O2 from
their microbal population
and their relation to microbes
(a) investigate forms and habitus
of microbially-induced calcium
carbonate,
Conducted mainly for limestones
forming in association with
Oocardium stratum, Rivularia,
Scytonema and diatoms
(b) determine the relation of
microbes to their calciumcarbonate precipitates
CP-SEM: investigation of samples
of actively-forming microbialite
taken in vivo in the field, and with
their microbial assemblages still in
place
Investigation of physico-chemistry
of limestone-precipitating spring
waters
Measurement of
Determination of
(a) in-situ: temperature, electrical
conductivity, pH, alkalinity,
(a) physico-chemistry of spring
waters that precipitate calcium
carbonate and, in a few cases,
other compounds (e.g. iron oxide)
(b) major kations and anions,
(c) free CO2,
Free CO2 and oxygen saturation to
date 2008 determined by us for
three springs; additional data are
taken from
Carlé (1975)
Kahler (1978)
Zötl & Goldbrunner (1993),
(d) oxygen saturation,
of active limestone springs, by:
(b) seasonal 'stability' of limestone
springs (in case of repeated
measurements)
Unterwurzacher (2001)
Determine numerical age of
samples of spring limestone
In the Eastern Alps, extremely few
age dates are available relative to
the total minimum number of SAL
deposits.
Determine the 'stability' of
limestone springs relative to
Method was used at three locations
(a) transportable WTW multiparameter detectors (T, pH, cond),
by Aquamerck® alkalinity titration
in the field,
(b) AAS, ICP, autoanalyzer,
(c) titration (CO2),
(d) titration (oxygen saturation)
Water samples for kations were
spiked with three drops of 5%
HNO3
Unspiked water samples for anions
or for complete kat-an analyses
were transported in a coolbox
234
U/230Th disequilibrium dating of
spring limestones
Samples of spring limestone
dissolved, contents of all U and Th
isotopes of samples are measured
by mass spectrometry.
Stable isotope ratios 18O, 13C of
limestone spring
Disturbed open-system
equilibrium between 234U and
230
Th can be used to age-date
limestones back to 500-700 ka b.p.
See Ostermann et al. (2006, 2007)
for detailed description of method
Measurement of 18O, 13C ratios
by mass spectrometry,
seasonal changes,
 O,  C ratios of limestoneprecipitating spring waters
18
13
18
(a) in bimonthly intervals ( O)
over two years,
(b) and in semi-annual intervals
(13C) over two years