sagnotti.qxp_Layout 6 ANNALS OF GEOPHYSICS, 61,3, DA341, 2018; doi: 10.4401/ag-7619 1 “STRATFIT: AN EXCEL WORKBOOK FOR CORRELATION OF MULTIPLE STRATIGRAPHIC TRENDS„ Leonardo Sagnotti1,* and Chiara Caricchi1 (1) Istituto Nazionale di Geofisica e Vulcanologia, Rome, Italy 1. INTRODUCTION The correlation of sedimentary stratigraphic trends from different basins and/or sections is a critical issue for all paleoenvironmental and paleoclimatic recon- structions, as well as for basin characterization in ex- ploration and characterization of georesources. In particular, the reconstruction of changes in climate and/or environmental conditions at a regional or global scale in the geological past is generally accomplished by detailed studies of stratigraphic variations of suit- able proxies in sedimentary sequences, whose tuning results in the set up of reference stack curves [e.g. global stack of oxygen isotope trends in marine sediments; Im- brie et al., 1984; Karner et al., 2002; Lisiecki and Raymo, 2005]. Stratigraphic correlation between dis- tinct sedimentary sections and/or reference stack curves is usually based upon signal matching between two or multiple records of appropriate proxies. This signal matching is an often difficult and tricky process, which requires multiple efforts to converge to- ward the most reliable solutions. Various attempts have been made in paleoclimate research to make correlation of stratigraphic trends easier. The different adopted ap- proaches span from simple correlation by eye matching of stratigraphic features, which is often time-consum- ing, to automated correlation [Martinson et al., 1982; Waterman and Raymond, 1987] or dynamic program- ming techniques [Lisiecki and Lisiecki, 2002]. These lat- ter techniques require the use of specific software and dedicated algorithms, which may not always be acces- sible or under the direct control of general users. In this manuscript, we propose a new user-friendly tool, the StratFit program consisting of a single Microsoft Excel workbook organized in worksheets, which allows an easy correlation of different stratigraphic curves and im- mediate visualization of the results. The StratFit program was conceived to address the Article history Receveid January 21, 2018; accepted April 10, 2018. Subject classification: Stratigraphy; Tie-points; Core correlation; Microsoft Excel workbook; Forecast function. ABSTRACT Correlation of distinct stratigraphic sequences is often critical to characterize evolution of sedimentary basins, as well as for exploration of georesources and for paleoenvironmental and paleoclimatic reconstructions. Stratigraphic correlation is usually based on signal match- ing between two or multiple proxies’ records. Commonly, stratigraphers have to approach the correlation issue with time-consuming meth- ods or specific software that may not be easily accessible or may not allow a full and direct control of the adopted procedure. In this work, we propose a new simple tool, which consists of a single Microsoft Excel workbook (that we named StratFit) organized in work- sheets and allows an easy correlation of different stratigraphic curves and immediate visualization of the results. The correlation pro- cess is based on the FORECAST function and linear regression between subsequent couples of selected tie-points. The program is open source, user-friendly and allows a full control of the correlation process since all the computations are accessible for user’s inspection and improvement. The StratFit workbook and the user manual are freely distributed and can be downloaded as supplementary material. needs related to the environmental magnetism analy- ses, as a tool to correlate two distinct stratigraphic sec- tions by taking into account multiple trends in rock magnetic and paleomagnetic parameters [Sagnotti et al., 2011a,2011b]. Due to the extensive use and distribution of Excel, the operability of this software is guaranteed over the longer term for different operating systems (e.g., Mac Os X, Microsoft Windows). Moreover, the program is open source, user friendly and all the computations are ac- cessible for user’s inspection and improvement. During the correlation process the user can immediately check every change on the graphs and most importantly can take into proper account all useful available informa- tion (e.g., 14C ages, lithological factors among others). Thus, the power of StratFit stems on the fact that this program allows an aware and interactive correlation of stratigraphic trends between two cores and not only an automatic passive match among peaks and troughs. Lastly, the program has the following features, which may be valuable for various users: i) compatibility with nearly all computers; ii) easy input of data by “copy and paste”, immedi- ate visualization of the results and easy export of plots; iii) modular structure in distinct worksheets for each selected stratigraphic trend; iv) easy and prompt visualization of the effects of the adopted matching on multiple stratigraphic trends (up to 11 distinct stratigraphic trends in the re- leased version, but easily expandable at wish); v) complete control of the whole workflow and pos- sibility of implementation of the workbook by users. In the following sections, we describe the software and its main features and applicability. 2. SOFTWARE DESCRIPTION The released version of StratFit workbook is orga- nized in 12 worksheets (Figure 1). The green one is the “Data” worksheet, where the user introduces data for the two cores (one of which considered as “master” and the other as the correlative core) and makes the choice of the tie-points for the cor- relation. The yellow sheets show the plots of the strati- graphic trends for each parameter, where the user can visualize and check the correlations. The correlation process is based on the FORECAST function which implies a linear regression between sub- sequent couples of selected tie-points. This process re- sults in the estimate of the equivalent depth of the correlated curve in the depth scale or age of the “master” curve. In detail the Excel FORECAST function predicts a fu- ture point on a linear trend line fitted to a supplied set of x- and y- values. The syntax of the function is: FORECAST( x, known_y’s, known_x’s ) Where the arguments are: i) x, a numeric value for which you want to forecast a new y-value; known_y’s, an array of known y-values; known_x’s, an array of known x-values. The known_y’s and known_x’s arrays correspond to pairs of coordinates defining consecutive tie-points linking the master and the correlative curves (i.e., depth yB of correlative core B linked to a depth xA of master core A). 2.1 DATA INPUT: GREEN WORKSHEET In the Data worksheet (marked in green) the user en- ters the stratigraphic data of selected parameters (up to 11 distinct parameters) for both the master (core “A”) and the correlative (core “B”) cores and select pairs of tie-points for correlation. The correlation process consists in matching the stratigraphic trends of up to 11 parameters from core B (listed in columns A to L, with headings marked in blue) with corresponding parameters from core A (listed columns T to AE, with headings marked in orange). This correlation is achieved by means of the tie-points, where a depth of B is associated with a depth of A. In detail, the user should copy the data of reference stratigraphic trends of the “master core” in columns T to AE (Figure 2a). Columns A to L must be filled with SAGNOTTI AND CARICCHI 2 42 43 44 Data Plot 01 Plot 02 Plot 03 Plot 04 Plot 05 Plot 06 Plot 07 Plot 09Plot 08 Plot 10 Plot 11 + Normal Visualization sum= 0 FIGURE 1. The StratFit Excel workbook is organized in 12 worksheets. The green one is the “Data” worksheet, where the user in- troduces data for the two cores and makes the choice of tie-point pairs for correlation. The yellow sheets show the plots of the stratigraphic trends for up to 11 distinct parameters, where the user can visualize and check the correlations re- sulting from the adopted tie-points. data of the correlative core (Figure 2b). Stratigraphic coordinates (depths, or ages) are listed in column T for the master core and in column A for the correlative core (Figure 2). The columns P and Q are dedicated to the input of selected pairs of tie-points chosen by the user to corre- late stratigraphic trends finding the best common depth (or age) (Figure 3a). The tie-points could be chosen ei- ther considering significant and coincident peaks and troughs of the curves or taking into account lithostrati- graphic correlations and/or the information coming from other available stratigraphic constraints (e.g., 14C ages). The common depth is computed in the column N according to the FORECAST function, resulting in a common depth by correlating each depth of core B to a corresponding depth of core A (i.e., in the stratigraphic framework of the master core). The stratigraphic frame- work (i.e., data in columns A and T) can also consist of ages rather than depths, of course. Columns AX, AY, AZ and BA include formulas (based on the VLOOKUP, INDEX and MATCH functions) used to find the tie-point pairs on which apply the FORECAST function, for each x value of correlative core B. These columns are colored in red and should not be edited during the use of the software (Figure 3b). Moreover, the Data worksheet includes a graph “Depth A vs Depth B”, to the right of column AE. This graph allows to visualize the relative variation in the sedimentation rate resulting from the chosen tie-point pairs (Figure 3c). 3 STRATFIT: A STRATIGRAPHIC CORRELATION TOOL <==> . Home Layout Tables Charts SmartArt Formula Data Revision StraFit.xlsx Paste Font Alignment Number Format Cells ThemesEdit Wrap Text Merge General Conditional Formatting Styles Actions Themes Arial G C S 10 Q40 A abc ,0 ,00 ,00 ,0 % 000 Aa Aa X A B C D E F G H I J K L Curve B = XX Curve B = XX DATA IN - CORRELATIVE CORE DATA IN - CORRELATIVE CORE - + 1 2 3 1 2 3 4 5 6 7 8 9 10 <==> . Home Layout Tables Charts SmartArt Formula Data Revision StraFit_general form.xlsx Paste Font Alignment Number Format Cells ThemesEdit Wrap Text Merge General Conditional Formatting Styles Actions Themes Arial G C S 10 Q40 A abc ,0 ,00 ,00 ,0 % 000 Aa Aa X T U V W Y Z AA AB AC ADX AE Depth A (cm) Depth A(cm) Curve A = XY DATA IN - MASTER CORE DATA IN - MASTER CORE - + 1 2 3 1 2 3 4 5 6 7 8 9 10 Parameter 11_AParameter 10_AParameter 09_AParameter 08_AParameter 07_AParameter 06_AParameter 05_AParameter 04_AParameter 03_AParameter 02_AParameter 01_A Parameter 11_AParameter 10_AParameter 09_AParameter 08_AParameter 07_AParameter 06_AParameter 05_AParameter 04_AParameter 03_AParameter 02_AParameter 01_A Depth B (cm) Depth B(cm) Parameter 11_AParameter 10_AParameter 09_AParameter 08_AParameter 07_AParameter 06_AParameter 05_AParameter 04_AParameter 03_AParameter 02_AParameter 01_A Parameter 11_AParameter 10_AParameter 09_AParameter 08_AParameter 07_AParameter 06_AParameter 05_AParameter 04_AParameter 03_AParameter 01_A Parameter 02_A Curve A = XY FIGURE 2. “Data” worksheet. a) Columns T to AE, where the user should list the data of reference stratigraphic trends of the “mas- ter core”. b) Columns A to L, where the user should list data of the correlative core. a) b) SAGNOTTI AND CARICCHI 4 2.2 GRAPHS OUTPUT: YELLOW WORKSHEET Each worksheet marked in yellow refers to a specific parameter and shows plots of the stratigraphic trends. On each sheet four graphs are reported. The graphs show i) the stratigraphic variation of the selected parameter in the stratigraphic coordinates (depth or age) of correlative core B (Figure 4a) ii) the stratigraphic variation of the selected parameter in the stratigraphic coordinates (depth or age) of master core A (Figure 4b); iii) the stratigraphic trend of the selected parameter in a common stratigraphic framework, after correlation of core B to core A, both as horizontal (Fig- ure 4c) and vertical (Figure 4d) plots. Observing the trends in the common stratigraphic framework, the ef- fects of the selected tie-point pairs on the stratigraphic matching can be promptly and easily visualized. 3. WORKING EXAMPLE The correlation process starts entering a first selec- tion of a few tie-points, derived from lithological ev- idence or available radiometric data, if available, or by a starting assumption about sedimentation rates. . Home Layout Tables Charts SmartArt StraFit.xlsx Paste Font Alignment NumberEdit GeneralArial G C S 10 A % 000 X L M N O R ZP Depth B - + 1 2 3 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Q S Depth A Tie-pointsTie-points Tie-points Depth B Depth A Depth A (cm) Depth A (cm) >> DGRM/DNRM Int Parameter 11_B Common Depth Depth (cm) 17601-3 correlated to 17603-3 DATA OUTPUT - Common Depth DATA IN - Tie-points DATA OUTPUT - Common Depth DATA IN - Tie-points 35 393 45 409 63 435 85 471 111 542 119 584 134 668 Common Depth Depth (cm) 17601-3 correlated to 17603-3 172 722 184 746 204 235 832 880 3.65E-01 2.76E-01 2.07E-01 1.54E-01 9.23E-02 4.04E-02 4.52E-02 8.69E-02 1.21E-01 1.58E-01 2.18E-01 7 8 9 10 11 12 13 14 15 16 17 393.00 394.60 396.20 397.80 399.40 401.00 402.60 404.20 405.80 407.40 409.00 y = 0.3816x - 105.74 0 50 100 150 200 250 0 200 400 600 800 1000 D ep th B Depth A . Home Layout Tables Charts SmartArt StraFit.xlsx Paste Font Alignment NumberEdit GeneralArial G C S 10 A % 000 X AXAWAVAU AY BA BBAZ - + 1 2 3 1 2 3 4 5 6 7 8 9 10 11 12 13 14 >> These colums include formulas - do not change These colums include formulas - do not change MIN DEPTH B REF MIN DEPTH B REF MAX DEPTH B REF MAX DEPTH B REF MIN DEPTH A REF MIN DEPTH A REF MAX DEPTH A REF MAX DEPTH A REF 393 409 393 409 393 409 393 409 393 409 393 409 393 409 393 409 393 409 393 409 409 435 35 45 35 45 35 45 35 45 35 45 35 45 35 45 35 45 35 45 45 35 45 63 FIGURE 3. “Data” worksheet. a) Columns P and Q where the user should insert selected pairs of tie-points. The common depth is computed in column N according to the FORECAST function. b) Columns AX, AY, AZ and BA include formulas used to find the tie-point pairs that should be used to apply the FORECAST function, for each x value of correlative core B. These columns are colored in red and should not be edited during the use of the software. c) Graph of Depth A versus Depth B. This plot helps to visualise the effects of the selected tie-points on the relative changes in sedimentation rates between the two stratigraphic sequences. a) b) c) 5 STRATFIT: A STRATIGRAPHIC CORRELATION TOOL This process results in an initial visualization of the correlation effects on all the selected stratigraphic trends. Afterwards, the match between the distinct stratigraphic trends can be revised and improved by changing and adding tie-points that link directly the main peaks and troughs of distinct stratigraphic trends. This method is very fast and direct and it al- lows the user to check immediately and simultane- ously the effects on the overall correlations among different parameters. In this way the user may identify the main tie-points for a core correlation that satisfy multiple parameters and stratigraphic trends. Practically, first of all, the user has to paste the data in the specific columns, and then he has to insert some initial tie-points in columns P-Q. For the correct mode of operation of the worksheet the last tie-point of depth B has to be higher than the last value of the depth B. The user then can start an iterative process of improving correlation by changing or adding tie- point pairs. The selection of tie-points correlating core B to core A has an effect on the relative changes in sedimenta- tion rates. This effect can be visualized in the graph “Depth A vs Depth B” in the Data worksheet. 0.00 0.01 0.01 0.02 0.02 0.03 0.03 0 100 200 300 N R M ( A /m ) Depth B (cm) NRM CURVE B= Core 17601-3 CURVE B= Core 17601-3 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0 100 200 300 400 500 600 700 800 900 1000 N R M ( A /m ) Depth A (cm) NRM CURVE A = Core 17603-3 CURVE A = Core 17603-3 CURVE B = Core 17601-3 CURVE A = Core 17603-3 0.00 0.005 0.010 0.015 0.020 0.025 0.030 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0 100 200 300 400 500 600 700 800 900 1000 N R M ( A /m ) N R M ( A /m ) Common Depth (cm) NRM 0.00 0.005 0.010 0.015 0.020 0.025 0.030 0 100 200 300 400 500 600 700 800 900 1000 0.00 0.02 0.04 0.06 0.08 0.10 0.12 C om m on D ep th ( cm ) NRM (A/m) NRM (A/m) FIGURE 4. a) Stratigraphic variation of the Natural Remanent Magnetization (NRM) in the stratigraphic coordinates (depth or age) of core B. b) Stratigraphic variation of the NRM in the stratigraphic coordinates (depth or age) of the core A. c, d) Strati- graphic trends of the selected parameter in a common stratigraphic framework, after correlation of core B to core A, both as horizontal (c) and vertical (d) plots. a) b) c) d) SAGNOTTI AND CARICCHI 6 1 2 3 4 5 6 7 8 9 9.74 m b sf ox 1 3 4 5 m b sf 5.37 2 16°00´E 0 1000 1500 500 m Bear Island m 00 4 m 00 3 m 00 01 m 00 2 m 0 02 m 001 17601 17603 m 00 01 m 0 05 1 0 10 20 Km m 00 1 m 00 51 m 0 03 m 00 2 SPITSBERGEN GREENLAND SEA BARENTS SEA ARCTIC OCEAN FIGURE 5. Bathymetric map of the Kveithola glacigenic trough with location of the cores here discussed. 1 2 3 4 5 6 7 8 9 9.74 m b sf 0 0.015 ΔGRM/ΔNRM 0.03 0.045 30 70 110 K (10-5 SI) 0.06 0.10 0.14 0.18 0.22 0.26 ARM (A/m) 26 MDFNRM(mT) 36 30 90 50 34 28 32 0 20 40 k (10-5 SI) 0.01 0.07 ARM (A/m) 60 20 40 MDFNRM(mT) 0 0.5 1 1.5 ΔGRM/ΔNRM 1 3 4 5 m b sf 5.37 2 0.050.03 0.05 0.1 NRMIntensity (A/m) 30 60 90 Incl (°) -260 -140 -20 120 220 Decl (°) 2 4 MAD (°) 00 6 M ID D LE S LO P E 17603-3 17601-3 NRM/k NRM20mT/ARM20mT RPInorm max 0. 0 0. 2 0. 4 0. 6 0. 8 1. 0 O U T E R S H E LF Decl (°) 30 60 90 Incl (°) MAD (°) -180 40 120 -40 NRMIntensity (A/m) 6 2 400.02 0 0.04 RPInorm max 0. 2 0. 4 0. 6 0. 8 1. 0 NRM/k NRM20mT/ARM20mT 0. 1 ox LEGEND Interlaminated faciesHeavy bioturbated facies Crudely layered faciesCoarse sand with shell debris IRD-rich facies Oxydized layer FIGURE 6. Stratigraphic trends of the rock magnetic and paleomagnetic parameters [Caricchi et al., 2018]. 7 STRATFIT: A STRATIGRAPHIC CORRELATION TOOL 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0 100 200 300 400 500 600 700 800 900 1000 A R M ( A /m ) Common Depth (cm) ARM CURVE A = Core 17603-3 CURVE B = Core 17601-3 668 668 x x 0.000 0.005 0.010 0.015 0.025 0.030 0.035 0.040 0.045 0.050 A R M ( A /m ) 0.000 0.005 0.010 0.015 0.025 0.030 0.035 0.040 0.045 0.050 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0 100 200 300 400 500 600 700 800 900 1000 A R M ( A /m ) A R M ( A /m ) Common Depth (cm) ARM CURVE A = Core 17603-3 CURVE B = Core 17601-3 644 668 x x 130 131 132 133 134 135 136 137 138 33.52 32.19 33.54 33.55 34.90 33.58 33.59 33.60 33.61 2.28E-02 2.35E-02 2.41E-02 2.46E-02 2.48E-02 2.47E-02 2.42E-02 2.34E-02 2.24E-02 3.60E-02 3.73E-02 3.87E-02 3.94E-02 3.89E-02 3.79E-02 3.69E-02 3.60E-02 3.52E-02 82.6 82.3 81.9 81.3 80.4 79.6 78.9 78.8 79.1 13.6 13.3 12.9 12.3 11.4 10.6 9.9 9.8 10.1 1.0 1.1 1.5 1.7 1.7 1.5 1.2 1.1 1.1 44.33 44.57 44.79 44.92 44.90 44.75 44.51 44.25 43.91 34.62 35.35 36.45 37.03 36.61 35.70 34.93 34.53 34.30 0.96 0.96 0.95 0.95 0.97 0.99 1.00 0.99 0.97 8.72E-03 1.14E-01 2.36E-01 2.78E-01 2.35E-01 1.48E-01 6.43E-02 6.77E-03 0.00E+00 0.55 0.59 0.59 0.60 0.58 0.60 0.59 0.57 0.54 628.71 632.77 636.84 640.90 644.97 649.03 653.10 657.18 661.23 Curve B = Core 17601-3 Depth B (cm) k (10E-05SI) NRM (A/m) ARM (A/m) Inc ChRM (°) MAD MDF (NRM) MDF (ARM) NRM20mT /ARM20mT (norm-max) NRM20mT/k (norm-max) ΔGRM /ΔNRM Common Depth Decl ChRM (°) A B C D E F G H I L MJ K N O Tie-Points Depth B Depth A 35 339 45 409 63 435 85 471 111 542 119 548 172 722 184 746 204 832 235 880 Tie-Points Depth B Depth A 35 339 45 409 63 435 85 471 111 542 119 548 172 722 184 746 204 832 235 880 150 710 134 668 FIGURE 7. Example of the tie-points choice and input. a) b) c) d) 3.1 CASE STUDY The example that we discuss refers to a study by Car- icchi et al. [2018], carried out on sediment cores col- lected in the continental margin of the North-western Barents Sea, south of Svalbard (Figure 5). The work aimed to correlate the sedimentary sequences across the continental slope and shelf of the Kveithola glacigenic system, through paleomagnetic and rock magnetic analyses. The stratigraphic trends of the measured rock magnetic and paleomagnetic parameters of Core 17601-3 (correlative core “B”, from the continental outer shelf) and Core 17603-3 (master Core “A”, from the continental slope) are shown in Figure 6. The initial tie-point pairs for core correlation were deduced from 14C ages and lithostratigraphic con- straints. Afterwards, the correlation has been refined through an iterative process aimed to improve the matching between peaks and troughs of paleomagnetic and rock magnetic parameters. To combine different peaks (or troughs) we adjusted the initial tie-points and added some additional tie-point pairs as in the exam- ple reported the Figure 7. Initial correlation implied, for example, the hypothesis that stratigraphic depth of 150 cm in the core B correlates to 710 cm in master core A. This assumption resulted in the plot shown in Figure 7a, referring to the stratigraphic trend of the ARM parameter, that is the intensity of the anhysteretic remanent magnetization, an artificial remanence pro- duced by the simultaneous application of an alternat- ing AF and a constant DC magnetic field, which depends on the concentration of ferrimagnetic miner- als in the sediment. From this plot, it is clear that the ARM peak of Core B resulting at a common depth of 644 cm following the correlation under the initial con- straints, matches closely the peak measured at 668 cm of depth in master Core A (Figure 7a). In this case the initial pair of tie-points was adjusted to improve the correlation and impose matching of the ARM peak ob- served in the two stratigraphic trends. To do this ad- justment, the proper data were found in the “Data” worksheet, searching in column N (Common depth) the value closest to 644 cm and finding the corresponding depth in the column A (Depth B) (Figure 7b). In this case the value is 134 cm, thus the new tie-points pair was defined as 134 - 688, which implies that depth 134 cm in core B was now linked to depth 668 cm in mas- ter core A. Typing these values in the tie-point columns SAGNOTTI AND CARICCHI 8 1 2 3 4 5 6 7 8 9 17603-3 m b sf 1 2 3 4 5 m b sf 17601-3 Interlaminated facies IRD-rich facies Heavy bioturbated facies Crudely layered facies Coarse sand with shell debris LEGEND Oxydized layer 0.0 0.5 1.0 1.5 2.0 2.5 3.0 0 0.02 0.04 0.06 0.08 0.01 0.12 0 100 200 300 400 500 600 700 800 900 1000 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 0 0.05 0.10 0.15 0.20 0.20 0 100 200 300 400 500 600 700 800 900 1000 0 0.2 0.4 0.6 0.8 1.0 1.2 Common Depth (cm) N R M ( A /m ) 17 60 3 A R M ( A /m ) 17 60 3 N R M ( 10 -2 A /m ) 17 60 1) A R M ( 10 -2 A /m ) 17 60 1 R P I ( N R M 20 m T /A R M 20 m T ) 17603-3 Depth (cm)17601-3 correlated to 17603-3 Common Depth (cm) Common Depth (cm) 0 100 200 300 400 500 600 700 800 900 1000 0 5 10 15 20 25 30 35 40 0 10 20 30 40 50 60 70 80 0 100 200 300 400 500 600 700 800 900 1000 k (1 0E -0 5 S I) k (1 0E -0 5 S I) Common Depth (cm) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 0 100 200 300 400 500 600 700 800 900 1 000 N R M 2 0m T /k _n or m -m ax Common Depth 0 10 20 30 40 50 60 70 80 90 100 0 100 200 300 400 500 600 700 800 900 1000 In cl C hR M ( °) Common Depth (cm) FIGURE 8. Resulting correlations between selected rock magnetic parameters of the stratigraphic sequences from the Kveithola continental slope and outer shelf. (Figure 7c) it is possible to visualize directly the effects of the change in the ARM stratigraphic trends from the two cores (Figure 7d), as well as on all the other con- sidered parameters, and then proceed with further anal- ogous adjustments until the overall match is satisfactory. This procedure allowed us to define a close correla- tion between slope and outer shelf sedimentary suc- cessions (Figure 8). 4. CONCLUSION The StratFit workbook is designed to deal with the correlation between two distinct stratigraphic sections by taking into account multiple stratigraphic trends. The released software improves and simplifies the correla- tion process. StratFit may be valuable for various users for the following attributes: - Compatibility with nearly all operating system; - Easy input of data; - Immediate visualization of the results; - Easy export of plots; - Modular structure in distinct worksheets for each selected stratigraphic trend; - Easy and prompt visualization of the effects of the adopted matching on multiple stratigraphic trends; - Full control of the whole workflow and possibility of implementation of the workbook by users. The StratFit workbook and the User manual may be download as supplementary material. We thank Alessandro Vona and Aldo Win- kler for testing the software. The two anonymous reviewers are kindly acknowledged for their suggestions that contributed to improve the paper. We also thank Fabio Caratori Tontini for the editorial handling. REFERENCES Caricchi, C., R.G. Lucchi, L. Sagnotti, P. Macrì, C. Morigi, R. Melis, M. Caffau, M. Rebesco, T. J. J. Hanebuth (2018). 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Geol., 19, 109 - 127. *CORRESPONDING AUTHOR: Leonardo SAGNOTTI, Istituto Nazionale di Geofisica e Vulcanologia, email: leonardo.sagnotti@ingv.itr © 2018 the Istituto Nazionale di Geofisica e Vulcanologia. 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