Purpose
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Peter Blum, October 2022 (another update)
Purpose of stratigraphic correlation on the JOIDES Resolution
Shipboard (during expedition)
- Minimize coring gaps
- Provide rapid correlations when drilling multiple holes to ensure core gaps in one hole are covered by core in another hole.
- Use of the secondary core logger (Special task multisensor logger, STMSL) in addition to the primary logger (whole-round multi-sensor logger, WRMSL) is highly recommended.
- Requires effective real-time communication with the "core tech" from the drilling crew to achieve drilling depth corrections in time to mitigate coring gaps.
- Construct core composite depth scale below seafloor (CCSF)
- Provide a first order correlation of all cores from multiple holes by depth shifting (affine translation without scaling)
- Construct sampling splice
- Provide a primary spliced section, consisting of core intervals from multiple holes.
- The primary splice shall represents as much as possible of the stratigraphic section at a drill site.
- Sample locations in the curated core (core depth below seafloor, method A, CSF-A) can be mapped easily to the splice using the core offsets that define the CCSF depth scale.
Typically on shore (post-expedition - optional)
- Map non-splice intervals into the the primary splice (includes stretching and squeezing).
- Scale the CCSF depth scale, and/or a modified/mapped variant of it, to other depth scale(s) to match the drillers depth below seafloor (DSF) scale or a wireline logging depth scale.
- Astronomical tuning of the final depth scale.
Workflow and tools
- The workflow for the correlation of stratigraphic records obtained from scientific ocean drilling cores requires multiple applications.
- The workflow summarized here is primarily for the shipboard tasks. However, most of it can be done on shore before and/or after an expedition.
Table 1. Tasks and tools for stratigraphic correlation on and off the JOIDES Resolution.
| TaskWorkflow | Data types | Tool on JR | Applicable on shore? | User guide |
|---|---|---|---|---|
| Prepare data for correlation | Non-image data | Correlation Downloader | Not a this time. Use already prepared data or ask JRSO staff for help. | |
| Image data | LORE (LIMS Online Reports) | Yes | ||
| ImageRedux: cull and resample images ImageResample (R script) | Yes | |||
| Correlate: shift cores and splice core segments | All non-image and image data | Correlator app | Yes | |
| Load shift offsets and splice interval data to the LIMS database | Affine tables Splice interval tables | SCORS Uploader and Manager | Yes but requires credentials to write to the LIMS database (and approval by project manager) | |
| Download data with CCSF (core composite depth below seafloor) depths | All data accessible from the LIMS database | LORE (LIMS Online Reports) | Yes |
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Figure 1-1. Stratigraphic correlation support (SCORS) workflow and tools.
Correlation Downloader
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