Imbrication
Preferred overlapping orientation of elongate or flat sediment clasts, commonly useful for reconstructing palaeoflow direction.
Language and route: English scientific use of Latin imbricāre ‘cover with overlapping tiles’, from imbrex ‘roof tile’. English scientific use of Latin imbricāre ‘cover with overlapping tiles’, from imbrex ‘roof tile’
Literal gloss: roof-tile overlap
The name and its history
First geological naming act not verified · First geological printed use not verified
- What does the word literally mean?
- Immediate borrowing/formation pathway: English scientific use of Latin imbricāre ‘cover with overlapping tiles’, from imbrex ‘roof tile’. Linguistic gloss: ‘roof-tile overlap’. This is not automatically the original namer’s stated reason.
- What did the original author mean?
- An architectural term was adopted to describe overlapping flat pebbles in gravel beds before sedimentologists systematically measured their orientations.
- Why was the name needed?
- Sedimentary workers needed a map-scale or outcrop-scale indicator of flow direction when ripples and cross-beds were absent.
- What evidence supported the original concept?
- Inclined pebble long axes and preferred dip directions measured at multiple sites; experimental and modern stream analogues explain some, not all, fabrics.
- How has geology changed the concept?
- Current direction requires consideration of clast shape, transport style, paleoslope and post-depositional deformation; one imbricated stone is not a reliable palaeocurrent.
Further historical context
An architectural term was adopted to describe overlapping flat pebbles in gravel beds before sedimentologists systematically measured their orientations.
Sedimentary workers needed a map-scale or outcrop-scale indicator of flow direction when ripples and cross-beds were absent.
Inclined pebble long axes and preferred dip directions measured at multiple sites; experimental and modern stream analogues explain some, not all, fabrics.
Current direction requires consideration of clast shape, transport style, paleoslope and post-depositional deformation; one imbricated stone is not a reliable palaeocurrent.
Editorial qualification
No first petrographic use independently established; process interpretation is retrospective, not a quoted coiner intention.
Related names
Sources
- British Geological Survey, Rock Classification Scheme, Volume 3 overview — Modern descriptive sedimentary classification; does not establish historical first use
- Wentworth (1922), A Scale of Grade and Class Terms for Clastic Sediments — Original 1922 classification paper, verified title/DOI and journal pagination; full article not transcribed
- USGS, Lithologic classification of geologic map units — Alternative modern operational vocabulary, including mudrocks