ulkoruuvimassat

Ulkoruuvimassat is a term used in geoscience to refer to the outer portions of core samples obtained during drilling operations. In many Arctic and subarctic exploration contexts, the core is recovered with an outer shell that is processed separately from the inner core. The outer mass provides rapid information on near-surface lithology, weathering, and potential contamination.

During core recovery, the outer shell may be kept intact or removed, then logged and stored separately. Analyses commonly include descriptive logging, thin-section inspection, and quick geochemical screening to identify alteration halos and avoid cross-contamination with the inner core.

They are susceptible to mud intrusion and mixing with overlying materials, so observers treat them as supplementary to the inner core data. Proper documentation of handling is essential to maintain data integrity.

The term appears in Greenlandic- and Nordic-language technical vocabularies, likely built from elements meaning outer, drill, and samples. The usage is not universally standardized across organizations. Related topics include drill core and core logging.