TECTONICS
Supporting Information for
TOPOGRAPHIC INHERITANCE AND GEOMORPHIC RESPONSE TO
INTRAPLATE ACTIVE FAULTING IN THE NORTHERN EDGE OF LUT BLOCK
(CENTRAL IRAN)
Gabriele Calzolari(1), Marta Della Seta(2)*, Federico Rossetti(1), Reza
Nozaem(3), Gianluca Vignaroli(1), Domenico Cosentino(1), Claudio Faccenna(1)
1Dipartimento
di Scienze, Università Roma Tre, Largo S. L. Murialdo 1, 00146 Roma, Italy
2Dipartimento
di Scienze della Terra, Sapienza Università di Roma, Piazzale Aldo Moro 5, 00185 Rome,
Italy
3Department
of Geology, Imam Khomeini International University, 34149-16818 Qazvin, Iran
Contents of this file
Text S1 and S2
Figure S1
Figure S2
Additional Supporting Information (Files uploaded separately)
Table S1
Introduction
Supporting Information are provided on the methodological procedures used in this
paper and in particular on: (i) OSL dating of Quaternary deposits to correlate them with
regionally constrained ones, to use the associated landforms as suitable geomorphic
markers and to provide a minimum age constraint to Quaternary faulting; and (ii)
statistical alluvial fan slope analysis to isolate the tectonic fingerprint in Quaternary
landscape evolution.
In particular we provide here details on: i) the sample preparation, measurement
techniques, equivalent dose measurement and age calculation adopted in OSL dating; ii)
the purposely-developed routine to extract elevation data points from the top surface
remnants of single alluvial fans. We also include the complete dataset obtained in the
alluvial fan slope analysis.
Text S1. OSL dating
Sample preparation
For each sample pure quartz was extracted for De measurements. In OSL lab, the
sample was treated firstly with 10% HCl and 30% H2O2 to remove organic materials and
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carbonates, respectively. After grain size separation, the fraction of 90-125 μm was
relatively abundant. As a result, this fraction was chosen for equivalent dose (De)
determination. The grains were treated with HF acid (40%) for about 40 min, followed by
10% HCl acid to remove fluoride precipitates.
Measurement techniques
Quartz OSL measurements were performed using an automated Risø TL/OSL-20
reader. Stimulation was carried out by a blue LED (λ=470±20 nm) stimulation source for
40 s at 130 °C. Irradiation was carried out using a 90Sr/90Y beta source built into the
reader. The OSL signal was detected by a 9235QA photomultiplier tube through a U-340
filter with 7.5 mm thickness.
Equivalent dose (De) measurement and age calculation
For De determination, SAR protocol was adopted. The preheat temperature is chosen
to be 240 °C for 10 s and cut-heat is 180 °C for 10 s. The final De is the average of Des
of all aliquots, and the error of the final De is the standard error of the De distribution.
For each sample, 20 aliquots were measured for De determination.
The Quartz OSL was fast component dominated. Recycling ratios were between
0.90-1.1. Recuperation is negligible. The cosmic ray dose rate was estimated for each
sample as a function of depth, altitude and geomagnetic latitude. The concentration of U,
Th and K was measured by ICP-MS. The elemental concentrations were then converted
into annual dose rate, taking into account of the water content effect. The final OSL age
is then: De/dose-rate.
Text S2. Statistical alluvial fan slope angle analysis
The routine for the statistical alluvial fan slope analysis encompasses the following
steps: i) clipping the DEM to the extent of each remnant of the mapped alluvial fans; ii)
creating a curvature map of each fan from the clipped DEM; iii) extracting from the
curvature map the areas with positive and low curvature values, likely corresponding to
the remnants of the fan top surface; iv) transforming these areas into a point cloud
containing elevation data. To capture the downstream changes in gradient angle along
the fans, this angle has been measured along the N-S direction by plotting a linear
regressions through the extracted and projected elevation point-cloud data, at 2-km
intervals, for sectors A, B, C, D indicated in Fig. 7b. A total of 71 alluvial fans were
analyzed using this method in areas “west” and “east” of Zone 1. An example of the
extracted alluvial fan top surface elevation data, the resulting linear regressions and the
obtained fan parameters, for a single alluvial fan are presented in Fig. S1 and the
complete dataset is listed in Tab. S1. Few slope data values from the same generation
of fan and the same sector have been discarded as tails if differing more than 1 from
the closest values. The average slope angle value populations (for each generation and
each sector) and the associated 1  error, after discarding the tails, have been used to
plot the results in Fig. 14.
Given the different degree of geomorphic reshaping of the three generations of
alluvial fans, we tested the proposed procedure to check whether some bias could have
affected the obtained slope values. To do this we plotted the slope values obtained for
different generations and different sectors versus each of the following variables: i) the
total fan area; ii) the number of data (n. of elevation points extracted from the top
remnants of each fan); iii) the % fan area coverage (% of fan area corresponding to the
top surface); iv) the N-S length (longitudinal extent of each fan remnant); and v) the data
density (n. of elevation point per meter, once projected them along the N-S axis of each
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fan). The plots in Figure S2 highlight that no correlations can be found between each of
this variables and the obtained slope values, thus confirming the suitability of the
procedure.
Figure S1. Example of extracted alluvial fan data plotted on a N-S transect and the
calculated slope for each sector. m= slope gradient, CendX=fan elevation at the northern
end of sector x.
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Figure S2. Plots used for the methodological test: the slope values obtained with the
proposed procedure for different generations and different sectors have been plotted
versus different variables indicative of the degree of reshaping of each fan.
<Table S1 is uploaded as separate file since it is longer than 1 page>
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Table S1. Complete dataset of the Quaternary alluvial fans slope angle analysis
performed for each fan of the three recognized generations. The analysis is performed
within each of the 2-km wide sectors (A to D), moving progressively far from the major
fault zone of the northern slope of the KFF ridge. m is the ratio between the elevation
and the N-S distance, from wich the slope angle is calculated; CendX is the elevation at
the northern end of sector X
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