A marine sediment concept defining how particles accumulate, are reworked, and change after burial on the seafloor. It governs depositional processes, physical properties, and post-depositional reactions measured through cores and laboratory analyses. It does not uniquely identify sources or processes without supporting stratigraphic, mineralogical, and geochemical evidence. It materially affects habitat, slope stability, and climate records by controlling the properties and composition of seabed deposits. The concept is generally stable, though analytical resolution and property measurement methods improve over time.

Principle

Maintain the original stratigraphic continuity, context, and physical integrity of the recovered core by minimizing manipulations so that the archive half remains a reproducible reference for future observations and reassessments.

Demonstration

On a research vessel, a piston core is split longitudinally; the archive half is photographed, described macroscopically, wrapped in inert material, refrigerated or frozen as required, and placed in a climate-controlled repository labeled with cruise ID, core ID, depth intervals and orientation marks.

Misapplication

Treating the archive half as expendable and performing destructive subsampling before adequate documentation, or assuming that the archive half is unaffected by prior handling and using it without verifying its condition.

Consequence

When preserved correctly, the archive half provides a stable, verifiable record enabling reanalysis with improved methods, cross-checks of earlier interpretations, and legal or regulatory review of stratigraphic claims.

Reversal

The working half: the complementary split portion that is deliberately sampled, subsampled, and altered to obtain materials and measurements, and therefore not preserved as the primary long-term record.

Boundary

Applies specifically to split core procedures where a physical longitudinal split produces two complementary halves; does not apply to unsplit whole-core samples, grab samples, surface grabs, drill cuttings, or crushed/subsampled material where no intact half remains.

Semantic Tension

Tension exists between preserving an untouched archive half for future use and the scientific pressure to make immediate measurements that may require sampling the same material; users must balance immediate data needs against long-term preservation.

Synthesis

The Core Archive Half is the intentionally preserved longitudinal half of a core that serves as the minimally disturbed, documented reference of the recovered sequence, kept to ensure reproducibility, future study, and verification while the complementary working half supports immediate destructive analyses.