Relative dating and unconformities
Superposition constrains age order in an undisturbed depositional sequence; inclusions predate their host, and cross-cutting features postdate what they cut.
Key knowledge
Superposition constrains age order in an undisturbed depositional sequence; inclusions predate their host, and cross-cutting features postdate what they cut. Unconformities record missing time through nondeposition and/or erosion. These relations can order events without assigning a numerical age.
Conditions and scope
- Overturning, fault repetition, reworking and intrusive relations require checking the geological context.
- A missing interval need not have a visually obvious angular discontinuity.
Sources · 1
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Evidence and review
Read superposition, inclusion, cross-cutting and four unconformity types, retaining disrupted-sequence limits.
2026-10-10 · Independent AI editorial review: All36 Life-authored Earth compact statements/conditions/displayed equations and all81 origin semantic links read; all36 author exact-source matrix rows and exclusions assessed. All18 inherited Earth compact records read for combined inventory. Targeted independent actual primary sections listed below; not every source body or proof independently reread. AI editorial reference review, not human certification/field proficiency or whole-field completion. Receipt: earth-life-independent-content-review.1.
Entry details
Permanent link to this entry ↗- Record identity
- uni-earth-stratigraphic-relations
- Revision
- core.1
- Structured reference record
- University core expansion