Inquiries: peter@ldeo.columbia.edu
This is Motif Version 2.1. (june 10, 1999, Peter deMenocal, L-DEO)
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Splicer is an interactive workstation software product for graphically displaying and depth-shifting multiple-hole core physical property and age-control data for constructing complete, composite stratigraphic records and timeseries.
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The program serves three main functions:
COMPOSITING - Optimal intercorrelation and depth-shifting of multiple-hole core data and development of the Composite Depth Scale.
SPLICING - Construction of complete, spliced sequences from multiple-hole data using the Composite Depth Scale.
AGE MODEL AND TIMESERIES DEVELOPMENT - The program also reads biostratigraphic and magnetostratigraphic age control data which can be displayed, depth-shifted, and applied to generate continuous time-series records from the spliced data records.
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Here is a general overview of how Splicer works:
1) Multisensor Track core data (GRAPE density, magnetic susceptibility, natural gamma activity, P-wave velocity, color reflectance) are read for any number of offset holes using the "OPEN..." menu item (under FILE). The user specifies data culling, smoothing, and decimating options. These data are plotted in the left-hand window as a series of channels, each channel represents the data from a given hole. Data from each core are presented as a single continuous trace; core numbers are shown at the lower left of each core.
2) Up to five different types of age control data (Nannofossil, foraminifera,radiolaria, and diatom biostratigraphy, and paleomagnetic reversal boundaries) can be read using the "OPEN/STRATIGRAPHY FILE..." menu item (under FILE). These data are plotted as a series of color-coded bars adjacent to the core data for each hole. There is a simple tab-delimited (Excel) format for stratigraphic files.
3) The user then selects the "COMPOSITE" menu item (under PROCESS) to begin linearly depth-shifting the core data from adjacent holes to intercorrelate all core data to a common (composite) depth scale. Using the COMPOSITE tool, the user selects tie points between holes based on visually correlative features. When a tie is made the program calculates the cross-correlation between the two records at the tie point and suggests an optimized tie point based on the best cross-correlation between the two cores. The user can then depth-shift this core (and all the others below it in that hole..) relative to the other cores. All user activity is stored in a REPORT FILE which keeps a time-stamped log of correlation and splicing activity for poserity purposes. The correlation proceeds downward stratigraphically on a core-by-core basis.
The resulting depth scale is referred to as the COMPOSITE DEPTH SCALE and depth values are in meters composite depth (mcd). The depth offsets required to construct the composite depth scale is stored in a file called an AFFINE TABLE. The AFFINE TABLE contains the depth adjustment values which must be applied to the depths of each core from each hole to (re)build the composite depth scale. These offset values can be applied to the biostratigraphic and magnetic polarity data and saved as separate files.
4) Once all data have been depth shifted to the composite depth scale then individual core segments can be selected and spliced together in the right-hand window to build a continuous, complete record. One begins splicing by selecting the SPLICE -> CONSTRAINED menu item (under PROCESS). (CONSTAINED means that the resulting splice preserves the composite depth scale established in the left-hand window; this is the preferred way to build a spliced composite record. UNCONSTRAINED means that the user can make a splice which differs slightly from the composite depth scale).
The SPLICE pop-up window allows the user to select the first core to begin splicing: The user clicks on any core with the center mouse button, hits the GRAB CORE button, and the core is redrawn in the left column of the right-hand panel. The user then selects a second core - the one which will be spliced below the first core - and it is drawn on the right column of the right window. The user then clicks any place where the two cores overlap (with the center mouse button) and the cross-correlation between the two cores at that point of overlap is shown. The user can drag (mouse button depressed) over the interval to find the best point to define the splice.
The program indicates a good splice position by flashing "This is a good splice" when the cross-correlation is centered and the difference between the tie point data values is less than 10% of the splice value. If the tiepoint is satisfactory then the user hits the SPLICE TO TIE button and the program splices the two core records at that point (trims the bottom off the left core and trims the top off the right core). The results can be stored in a SPLICE TABLE which defines the ODP identifier, mbsf, and mcd tiepoint data to rebuild the spliced record.
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updated: 15 February, 1997
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