a fragment of (sedimentary) rock broken off from a larger rock
clast in American English
(klæst)
noun
a grain of sediment, silt, sand, gravel, etc., esp. as a constituent fragment of a clastic rock formation, as distinguished from a chemical or biogenic component of such a formation
Word origin
[1950–55; prob. back formation from clastic]This word is first recorded in the period 1950–55. Other words that entered Englishat around the same time include: Common Market, action painting, bleep, conflict of interest, wiretap
Examples of 'clast' in a sentence
clast
Dominance of oblate fabrics indicates clast imbrications imposed by compaction and welding.
Hoabin Hong, Yongjae Yu, Seong-Jae Doh, Dongwoo Suk, Jeongmin Kim 2016, 'Magnetic Fabrics and Source Implications of Chisulryoung Ignimbrites, South Korea',Frontiers in Earth Sciencehttp://journal.frontiersin.org/Journal/10.3389/feart.2016.00079/full. Retrieved from DOAJ CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)
Within the studied samples a transition from clast to matrix supported conglomerates was observed.
Csibri Tamás, Rybár Samuel, Šarinová Katarína, Jamrich Michal, Sliva Ľubomír, KováčMichal 2018, 'Miocene fan delta conglomerates in the north-western part of the Danube Basin: provenance,paleoenvironment, paleotransport and depositional mechanisms', Geologica Carpathicahttp://www.degruyter.com/view/j/geoca.2018.69.issue-5/geoca-2018-0027/geoca-2018-0027.xml?format=INT. Retrieved from DOAJ CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)
This carbonate debris can be divided into clast-supported facies and matrix-supported facies.
Gadjah E. Pireno, Emmy Suparka, Dardji Noeradi, Alit Ascaria 2015, 'Porosity and Permeability Development of the Deep-Water Late-Oligocene Carbonate DebrisReservoir in the Surroundings of the Paternoster Platform, South Makassar Basin, Indonesia',Journal of Engineering and Technological Scienceshttp://journals.itb.ac.id/index.php/jets/article/view/746/1096. Retrieved from DOAJ CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)
The matrix-supported facies have much better porosity and permeability than the clast-supported facies.
Gadjah E. Pireno, Emmy Suparka, Dardji Noeradi, Alit Ascaria 2015, 'Porosity and Permeability Development of the Deep-Water Late-Oligocene Carbonate DebrisReservoir in the Surroundings of the Paternoster Platform, South Makassar Basin, Indonesia',Journal of Engineering and Technological Scienceshttp://journals.itb.ac.id/index.php/jets/article/view/746/1096. Retrieved from DOAJ CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)
Conglomerates are polymictic, clast- to matrix-supported, with clasts and matrix entirely composed of local bedrocks.
Jasenka Sremac, Josipa Velić, Marija Bošnjak, Ivo Velić, Davor Kudrnovski, TamaraTroskot-Čorbić 2018, 'Depositional Model, Pebble Provenance and Possible Reservoir Potential of CretaceousConglomerates: Example from the Southern Slope of Medvednica Mt. (Northern Croatia)',Geoscienceshttps://www.mdpi.com/2076-3263/8/12/456. Retrieved from DOAJ CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)
The cm-sized clast contains abundant large organic grains or aggregates up to 20 μm in phyllosilicate-rich matrix.
Yoko Kebukawa, Motoo Ito, Michael E. Zolensky, Richard C. Greenwood, Zia Rahman, HirokiSuga, Aiko Nakato, Queenie H. S. Chan, Marc Fries, Yasuo Takeichi, Yoshio Takahashi,Kazuhiko Mase, Kensei Kobayashi 2019, 'A novel organic-rich meteoritic clast from the outer solar system', Scientific Reportshttp://link.springer.com/article/10.1038/s41598-019-39357-1. Retrieved from DOAJ CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)
The components build a clast-supported framework.
M. Spiske, R. B. Halley 2014, 'A coral-rubble ridge as evidence for hurricane overwash, Anegada (British Virgin Islands)',Advances in Geoscienceshttp://www.adv-geosci.net/38/9/2014/adgeo-38-9-2014.pdf. Retrieved from DOAJ CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)
Structural sediments such as graded bedding of fining upward, parallel lamination and soil clast were found.
Yudhicara Yudhicara, Andrian Ibrahim 2017, 'SEDIMENTOLOGICAL PROPERTIES OF THE 2010 MENTAWAI TSUNAMI DEPOSIT', Bulletin of the Marine Geologyhttp://ejournal.mgi.esdm.go.id/index.php/bomg/article/view/45. Retrieved from DOAJ CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)
Finally, we conclude that the individual sets of clast fabric usually indicate only local debris-flowdirections.
P.P. Woźniak, M. Pisarska-Jamroży, Ł. Elwirski 2018, 'Orientation of gravels and soft-sediment clasts in subaqueous debrites – implicationsfor palaeodirection reconstruction: case study from Puck Bay, northern Poland', Bulletin of the Geological Society of Finlandhttp://www.geologinenseura.fi/bulletin/Volume90/Bulletin_vol90_2_161-174_2018_Wozniak-etal.pdf. Retrieved from DOAJ CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)