1. About Correlator 4.0

The Correlator application facilitates stratigraphic correlation of cores from multiple holes at a drill site. Its features support

• depth shifting of cores based on high-resolution core logging data, including images, to construct a core composite depth below sea floor (CCSF) depth scale; and
• splicing of selected core intervals to construct the most complete stratigraphic representation possible at a site. 

On the JOIDES Resolution (JR), the Correlator application documented here is used in conjunction with other applications within the stratigraphic correlation support (SCORS) ecosystem (Fig. 1-1), which are covered in a separate user guide (Table 1-1). 

Figure 1-1. Stratigraphic correlation support (SCORS) applications.

Table 1-1. Stratigraphic correlation support (SCORS) application documentation

Version 4.0 beta was released in April 2022. It can be downloaded at

<GitHub link>

On the JR you don't need to download the application - access will be obvious, or assisted by JRSO staff.

Correlator installs a directory for its internal database at a default location that looks something like this:

• Documents [or other system folder] > Correlator > 4.0 > db | default.cfg | log | temp

When you import correlation data from a directory of choice, Correlator indexes the data and places them in this directory for internal use. You don’t have to be aware of this directory but can change the path if needed (Fig. 1-2).

Figure 1-2. Correlator File menu.

Affine tables created in Correlator versions 3 and 4 differ from those in version 2: they include additional information (last three columns, see Appendix 2) that allow Correlator to reconstruct the relationship between cores. Affine tables created in the production version, 2.1_rc2 can still be imported in 4.0 by right-clicking "Saved Tables" in the Data Manager (available once data are loaded) and choosing Import legacy affine table. However, because legacy affine tables have no record of the reference core used to create a TIE, all cores shifted by a TIE will be converted to status REL on import into 4.0. This has no effect on their cumulative offsets, which will be preserved, but users will have to rebuild the TIEs manually (as was the case in version 2). 

2. Correlator basic functions overview

2.1. Data Manager and Display views

Correlator operates within a single window that can be expanded as much as available monitor space permits. The window can be toggled between the Data Manager view (Fig. 2.1-1) and the Display view (Fig 2.1-2). To navigate between these views, use the top button on the floating tool bar (Figs. 2.1-1 and 2.1-2), which is always available on top of either view unless turned off in the View menu.

Figure 2.1-1. Data Manager view. Also shown is the floating tool bar, where the top button can be used to toggle to the Display view.

 
The Data Manager view has two functional tabs across the top:

• The Data Manager tab (Fig. X) lists the files imported into Correlator and provides the functions for adding and managing the data in Correlator.
• The Generic Data tab displays data from files being imported when such an import is triggered in the Data Manager tab (otherwise it’s an empty grid). 

Figure 2.1-2. Display view, with the Display Preferences tab open on the right.

 
The Display view has three areas, two for data plotting and one for the functional controls, organized in four control tabs.

• The left plot area is for depth shifting, and the corresponding controls are in the Shift Cores tab.
• The right plot area is for the construction of splices, and the corresponding controls are in the Splice Cores tab. This plot area can be turned off at the top of the Display Preferences tab (shown in Fig. X) if more display space is preferred for depth shifting.
• The control area can be toggled among the following four tabs:
  • Close: This tab acts like a button and closes the control panel. The control panel can be opened again by clicking any of the other four tabs.
  • Shift Cores: This tab has controls for depth shifting, which are described in the Depth shift cores section.
  • Splice Cores: This tab has controls for splicing, which are described in the Construct the splice section.
  • Display Preferences: This tab has general data display controls, as shown in Fig. X.
  • Data Filters: This tab offers data filtering options, including decimate, smooth and cull (Fig. X).

2.2. Data Filters

2.3. Display Preferences

3. Manage data in Correlator

3.0. Overview of data management functions

(Move up from 2.6.)

3.1. Import primary correlation data

(Update)

3.2. Import core section summary files

(Update)

3.3. Import core section images

Important:

• You must first import some primary correlation data (and the associated section summary data) before you can import images.
• The images must be JPEG format and in the order of ~200 kb each, which is sufficient for most correlation purposes. Try higher resolution at your own risk.

To import images:

• Right-click on Images in the Data Manager window.
• Navigate to your local data directory
• Select the folder containing the JPEG images you want to import and click import.

3.4. Load data for correlation

(Update)

3.5. Update Correlator data

(Update)

3.6. Export data

Export affine and splice tables

(Update)

Export correlation data

(Update)

Export spliced data and images

(New)

4. Depth shift cores

4.1. Depth shift concepts

(Update)

4.2. Shift cores with the TIE method

(Update)

4.3. Shift cores with the SET method

(Update)

4.4. Undo shifts

(Update)

4.5. Manage affine tables

(Update)

5. Construct the splice

5.1. Splice concepts

(update)

5.2. Create a basic splice

(update)

5.3. Insert a core into an existing splice

(update)

5.4. Shifting cores that are already part of a splice

Concept and rules

Ideally, depth shifting should be concluded before a splice is assembled. However, life is not ideal and you may want to shift a core after you have constructed a splice. Because splice intervals are defined by their CCSF depths, shifting their cores invalidates the splice interval boundaries. A core shift results in a gap, an overlap, or both in the splice, depending whether a chain of tied cores or a single core are shifted, and whether the core(s) are shifted up or down. Correlator will deal with each situation in a clearly defined manner and provide you with relevant information.

Splice intervals boundaries are specified relative to the CCSF depth scale defined by the core sifts. The reason we select a certain core interval as being a splice interval is based on our interpretation of core quality based on the proxy data used to correlate the cores. The interval is therefore intrinsically defined by the the core-section-offset-in-section identity. When we shift cores we want to preserve that intrinsic splice interval. Therefore:

• Rule 1: Splice intervals are shifted with the cores they are associated with.
  • This inevitably creates at least one gap or one overlap in splice intervals.
• Rule 2: Overlaps in splice intervals are automatically resolved by 'clipping' the redundant part of the interval that is shifting.
  • We can do that because both overlapping intervals were approved as suitable for the splice and which one to use is typically a toss-up. You can always move the spice interval boundary very easily if that is not your desired solution.
  • The core-section-offset identity of the clipped splice interval boundary is reverse-computed from the CCSF depth to the CSF-A depth, from where the offset (cm) from top of section is obtained.
• Rule 3: Gaps created by the shifting of splice intervals are left open and you need to go and close them.
  • We prefer not to do that automatically because the interval needed to close the gap has not explicitly been assigned to the splice.

Example

Here is an example of your options and the program's responses when you shift cores that are part of a splice.

Case 1: Shift chain down

'This core and all related cores below' down

• You define a new tie from REF core A3 to SHIFT core B3 where the tie point in SHIFT core B3 is dz m shallower than the REF tie point in A3. This means the SHIFT core will shift down (Fig. X).
• You select “This core and all related cores below”
• The program asks for confirmation of the action (Fig. X), and assuming you OK it:
  • Replaces the previous tie with the new tie and shifts core B3 with all related cores from all holes that are deeper than REF core A3 downwards by dz m, maintaining all ties below the new one.
  • Shifts all splice intervals from from the shifting cores downwards by dz.
  • Creates a gap of length dz between splice intervals A3 and B3 and extends the CCSF scale by dz m.
• You cover the splice gap with a segment from either core A3 or B3, or partially with segments from both cores - it is up to you to decide.

Fig. X. Dialog for repairing a splice gap 

Figure X. Dialog for non-existent core interval. 

• • This solution is not valid, interval boundary falls outside the core.
  • Click the OK button and you return to the four options.

• The third option on the menu allows users to cover the gap with a combination of extensions from both splice intervals using the normal interactive splicing interface.
• The final option cancels the shift and nothing happens to cores or splice intervals.

Case 2: Shift chain up

'This core and all related cores below' up

• Define a new tie from REF core A3 to SHIFT core B3 where the tie point in SHIFT core B3 is dz m deeper than the REF tie point in A3. This means the SHIFT core will shift up (Fig. X).
• Select “This core and all related cores below” and click OK.
  • Results are analogous to those described in previous case.
• Because this action has shortened the CCSF scale, an overlap is created at the top of the splice interval representing the shifted cores. The overlap can be removed completely with a segment from either core A3 or B3, or partially with segments from both cores - it is up to you to decide. Correlator offers you the options in a pop-up window (Fig. X).

Figure X. Dialog for repairing a splice overlap. 

• • "This shift creates an overlap in the splice. How do you want to proceed?’
    • Clip the splice interval from core A3
    • Clip the splice interval from core B3
    • Leave the overlap and let me fix the splice manually
    • Cancel shift

• The first two options apply an “auto-fix”.  The calculated sample identity is validated and if the section-offset doesn’t actually exist in the same core, an error dialog is presented (Fig. X).

Figure X. Dialog for non-existent core interval.

• • This solution is not valid, interval boundary falls outside the core.
  • Click the OK button and you return to the four options.

• The third option on the menu allows users to remove the overlap with a combination of clipping parts from both splice intervals using the normal interactive splicing interface.
• The final option cancels the shift and nothing happens to cores or splice intervals.

Case 3: Shift single core down

'This core only' up

• Define a new tie from REF core A3 to SHIFT core B3 where the tie point in SHIFT core B3 is dz m shallower than the REF tie point in A3. This means the SHIFT core will shift down (Fig. X).
• Select “This core only” and click OK:
  • Replaces the previous tie with the new tie and shifts core B3 downwards by dz m.
• Because this action has not changed the total length of the CCSF scale, a gap is created at the top of the core and an overlap is created at the bottom of the core. The gap and overlap can each be repaired in two ways (see the first two cases) and Correlator therefore simply reminds you to do so yourself using the normal splice interface, or cancel the shift (Fig. X):

Fig. X. Dialog for repairing a single core splice gap and overlap.

• • "This shift creates a gap and an overlap in the splice. The splice interval associated with this core is therefore deleted and you need to splice it in again".
  • Cancel shift

Case 4: Shift single core up

'This core only' up

• Define a new tie from REF core A3 to SHIFT core B3 where the tie point in SHIFT core B3 is dz m deeper than the REF tie point in A3. This means the SHIFT core will shift up (Fig. X).
• Select “This core only” and click OK:
  • Replaces the previous tie with the new tie and shifts core B3 upwards by dz m.
• Because this action has not changed the total length of the CCSF scale, an overlap is created at the top of the core and a gap is created at the bottom of the core. The gap and overlap can each be repaired in two ways (see the first two cases) and Correlator therefore simply reminds you to do so yourself using the normal splice interface, or cancel the shift (Fig. X):

Fig. X. Dialog for repairing a single core splice gap and overlap.

• • "This shift creates a gap and an overlap in the splice. The splice interval associated with this core is therefore deleted and you need to splice it in again".
  • Cancel shift

5.5. Manage splice tables