Blockfield
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A blockfield [1] (kuma spelt block field [2]), felsenmeer, [1] Filin dutse [2] ko Filin dutse wani wuri ne da dutse- ko dutse-girman dutse yawanci yana da alaƙa da tarihin aikin dutse, yanayin alpine da subpolar da periglaciation. Blockfields sun bambanta da screes da talus gangara a cikin wannan blockfields ba su da asali daga lalacewar taro. An yi imanin cewa an kafa su ne ta hanyar sanyi a ƙasa.[3] Wani madadin ka'idar cewa wuraren da ke cikin zamani na iya samo asali ne daga yanayin sinadarai wanda ya faru a cikin Neogene lokacin da yanayin ya fi zafi. Biye da wannan tunanin za a sake yin aiki da wuraren ta hanyar aikin periglacial. [3][4]
Yawancin sanannun wuraren da aka sani suna cikin arewacin arewa. Ana iya samun misalai a cikin Abisko National Park a Sweden, Snowdonia National Park a Wales, Great End-Scafell Pike ridge a Ingila, da Hickory Run Boulder Field da River of Rocks a cikin Dutsen Appalachian na Amurka. Dukkanin misalai sai dai na farko suna waje da yankunan yanayi na yanzu, kuma saboda haka an ga su a al'ada a matsayin siffofi na asali daga lokutan da suka gabata lokacin da waɗannan yankuna ke ƙarƙashin periglaciation.
Kalmar "felsenmeer" ta fito ne daga ma'anar Jamusanci "teku na dutse". A cikin felsenmeer ko blockfield, sanyi-thaw yanayi ya karya saman dutsen, yana rufe tsarin dutse na ƙasa tare da jagged, duwatsu masu kusurwa. Rashin sanyi ko sanyi yana faruwa ne lokacin da ruwan da aka kama tare da microcracks a cikin dutse ya fadada kuma kwangila saboda sauye-sauye a cikin zafin jiki sama da ƙasa da yanayin daskarewa. An kafa Felsenmeers a wurin, ma'ana cewa ba a jigilar su a lokacin ko bayan halittar su.
Halaye
[gyara sashe | gyara masomin]Felsenmeers kawai suna haɗuwa a kan gangaren 25 ° ko ƙasa. Wani kusurwa mai tsawo yana haifar da jigilar tubalan saboda nauyi. Wannan yana haifar da gangaren tudun, maimakon felsenmeer. Za'a iya ganin rarrabawar ƙuƙwalwa tare da haɗin dutse a wasu lokuta a saman felsenmeers.
Bayani
[gyara sashe | gyara masomin]Rashin zurfin filin dutse ya dogara da kusurwar gangara, nau'ikan dutse, shekaru, da tarihin rushewa. Koyaya, matsakaicin matsakaici don zurfin felsenmeer kusan 1 m. Ballantyne (1998) ya bayyana nau'ikan bayanan felsenmeer guda uku: Nau'in 1 ya ƙunshi duwatsu da ke rufe matrix na tarar a wasu zurfin ƙasa da farfajiya. Nau'in 2 ya ƙunshi duwatsu da ke goyan bayan matrix mai yashi wanda ba shi da haɗin kai wanda ke ci gaba daga farfajiya zuwa ƙasa ta hanyar bayanin martaba. Nau'in 3 kuma ya ƙunshi duwatsu da ke goyan bayan matrix, amma ya bambanta da nau'in 2 saboda matrix ya ƙunshi yashi da / ko yumɓu maimakon yashi.
Abubuwan da suka faru
[gyara sashe | gyara masomin]Saboda bukatun gangara galibi ana samun su a kan tsaunuka. Basalt da duwatsu masu laushi sau da yawa suna samar da mafi girma, mafi yawan felsenmeers fiye da sauran nau'ikan dutse. Blockfields galibi ana samun su a cikin tsaunuka masu tsawo a kusa da Arctic Circle, musamman a Iceland, Canadian arctic da Norway kuma har yanzu suna aiki a wasu sassan Tsakiyar Turai waɗanda ba a rufe su da Kanada ba.[2] A cikin Kudancin Kudancin Hemisphere ana iya samun wuraren da ba su da aiki a cikin Lesotho Highlands, da kuma Tsibirin Prince Edward.[5][6]
Shekaru
[gyara sashe | gyara masomin]Felsenmeers, yawanci, ƙananan siffofin geomorphological ne. Yawancin felsenmeers sun samo asali ne a lokacin ko tun lokacin kankara na ƙarshe (kimanin shekaru 20,000 da suka gabata). Sauran na iya zama siffofi na pre-glacial waɗanda suka tsira daga glaciation a ƙarƙashin glaciers masu sanyi. Za'a iya ƙayyade takamaiman shekarunsu ta amfani da kwanan wata, dabarar da ke aiki mafi kyau a kan kayan da aka fallasa ga hasken sararin samaniya tare da ɗan tsangwama daga bishiyoyi ko ƙasa.
Manazarta
[gyara sashe | gyara masomin]- 1 2 Whittow, John (1984). Dictionary of Physical Geography. London: Penguin, 1984, pp. 66 and 190. ISBN 0-14-051094-X.
- 1 2 3 Leser, Hartmut, ed. (2005). Wörterbuch Allgemeine Geographie, 13th ed., dtv, Munich, pp. 107 and 221. ISBN 978-3-423-03422-7.
Cite error: Invalid
<ref>tag; name "Leser" defined multiple times with different content - 1 2 Goodfellow, B.W.; Stroeven, A.P.; Fabel, D.; Fredin, O.; M.-H., Derron; Bintnja, R.; Caffee, M.W. (2014). "Arctic–alpine blockfields in the northern Swedish Scandes: late Quaternary – not Neogene". Earth Surface Dynamics. 2 (2): 383–401. Bibcode:2014ESuD....2..383G. doi:10.5194/esurf-2-383-2014. Archived from the original on 2 April 2019. Retrieved 11 July 2016.
- ↑ Boelhouwers, Jan (2004). "New Perspectives on Autochthonous Blockfield Development". Polar Geography. 28 (2): 133–146. doi:10.1080/789610122. S2CID 129295656.
- ↑ "Geomorphic and climatic implications of relict openwork block accumulations near Thabana-Ntlenyana, Lesotho". Geografiska Annaler: Series A, Physical Geography. 86 (3): 289–302. 2004. doi:10.1111/j.0435-3676.2004.00232.x. S2CID 128774864.
- ↑ Boelhouwers, Jan; Holness, Steve; Sumner, Paul (2003). "The maritime Subantarctic: a distinct periglacial environment". Geomorphology. Elsevier. 52 (1): 39–55. Bibcode:2003Geomo..52...39B. doi:10.1016/S0169-555X(02)00247-7.