冰透鏡(英語:Ice lense)是當水分在土壤或岩石中擴散時, 在局部區域積聚時,若溫度降低形成的冰體。冰最初聚集在孔隙或裂縫中,只要水分能繼續補充,溫度低於冰點,冰就會繼續聚集並成長成透鏡體,將土壤或岩石楔開[1]。冰透鏡平行於地表生長,在土壤或岩石中深達幾厘米到幾分米(英寸到英尺)。 在1990 年的研究表明,冰解離(ice segregation)比凍融能更有效造成岩石的破裂[2] [3]

在北極苔原中,由於週期性的冰透鏡形成而造成Pingo

冰透鏡的形成由凍脹引起土壤隆起和基岩斷裂的關鍵作用,是在寒冷地區的主要風化作用。凍脹會產生岩石碎片,並改變景觀。儘管在冰緣地區(高山、亞極地和極地)的岩石破裂通常歸因於孔隙和裂縫中的水的凍結和體積膨脹,但大部分凍脹和基岩破裂是由冰解離和冰透鏡生長引起的[4]

凍脹是指當水向上進入到土壤中的冰凍溫度深度時,就結冰引起土壤向上膨脹[5]。冰的生長需要供水,由土壤中的毛細作用將水輸送。由於上覆土壤的重量,限制了冰的向上生長,就在土壤內形成一個透鏡狀冰區域。土壤必須有足夠的孔隙度讓水性通過毛細管作用上升,但孔隙度又不能太高到破壞毛細管的連續性[6][7]

參考文獻

  1. ^ Walder, Joseph; Hallet, Bernard (March 1985). "A theoretical model of the fracture of rock during freezing". Geological Society of America Bulletin. Geological Society of America. 96 (3): 336–346. Bibcode:1985GSAB...96..336W. doi:10.1130/0016-7606(1985)96<336:ATMOTF>2.0.CO;2.
  2. ^ "Periglacial weathering and headwall erosion in cirque glacier bergschrunds"; Johnny W. Sanders, Kurt M. Cuffey, Jeffrey R. Moore, Kelly R. MacGregor and Jeffrey L. Kavanaugh; Geology; July 18, 2012, doi:10.1130/G33330.1
  3. ^ Rempel, A.W. (2007). "Formation of ice lenses and frost heave". Journal of Geophysical Research. American Geophysical Union. 112 (F02S21): F02S21. Bibcode:2007JGRF..11202S21R
  4. ^ Murton, Julian B.; Peterson, Rorik; Ozouf, Jean-Claude (17 November 2006). "Bedrock Fracture by Ice Segregation in Cold Regions". Science. 314 (5802): 1127–1129. Bibcode:2006Sci...314.1127M. doi:10.1126/science.1132127. PMID 17110573. S2CID 37639112
  5. ^ Peterson, R. A.; Krantz , W. B. (2008). "Differential frost heave model for patterned ground formation: Corroboration with observations along a North American arctic transect". Journal of Geophysical Research. American Geophysical Union. 113: G03S04. Bibcode:2008JGRG..11303S04P. doi:10.1029/2007JG000559.
  6. ^ Taber, Stephen (1929). "Frost Heaving" (PDF). Journal of Geology. 37 (5): 428–461. Bibcode:1929JG.....37..428T. doi:10.1086/623637. S2CID 224836578. Archived from the original on 2013-04-08. Retrieved 2010-03-24.
  7. ^ Rempel, A.W.; Wettlaufer, J.S.; Worster, M.G. (2001). "Interfacial Premelting and the Thermomolecular Force: Thermodynamic Buoyancy". Physical Review Letters. 87 (8): 088501. Bibcode:2001PhRvL..87h8501R. doi:10.1103/PhysRevLett.87.088501. PMID 11497990.