南土狼丘
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南土狼丘（英語：Coyote Buttes South）是位於美國亞利桑那州的一個旅遊勝地，靠近猶他州北部邊界。與波浪谷及白袋地區兩旅遊勝地均位於科羅拉多高原內的帕里亞峽谷-朱紅懸崖荒野區的狼丘上。屬猶他州卡納布大階梯-埃斯卡蘭特國家紀念區的土地管理局管理[1]。
該地區因早期河流切割形成許多孤立的小丘，並出露其色彩鮮明的砂岩地層[2]，而廣為人知。出露的風成砂岩呈現大規模的交錯層理，加上由差異風化所造成的凹凸層面，更引人入勝。由於地層脆弱而限制入境人數，發放許可證採用每日現場抽籤系統（最多16人）及每月線上抽籤系統（最多48人）[3][4]。
在南土狼丘也可以看到如同白袋地區的花椰菜岩，但是棕色的，分佈在小丘頂上。大部分出露在南土狼丘的砂岩都呈現厚層交錯層理的曡加。在區域地質剖面其沉積層面趨近水平，代表無區域性構造運動。也證實了科羅拉多高原的穩定性構造。同理恐龍腳印在水平地面上，而不在斜坡上，也證實該地區的構造穩定性。在此地不同程度的風蝕地貌顯出不同程度的差異侵蝕. 從初始的凹凸層理，深切層理到只剩下的骨架。 有的呈現出洋蔥狀剝離。也有形同波浪谷的地貌，但規模較小。
地質
[編輯]南狼丘如同波浪谷及白袋地區一樣，均由侏羅紀納瓦荷砂岩（Navojo Sandstone）組成並暴露了大面積風成砂岩內的疊加交錯層理[5]。每一套交錯層理由有規律的交替顆粒流和風紋層組成[6]，並和上下套由沉積層面隔開。每一套交錯層理方向和傾斜角與上下套不同，代表了侏羅紀時期沙丘在沙漠中，被盛行風吹移的變化[7]。由於顆粒流和風紋層具不同的抗侵蝕能力而造成差異侵蝕。這些差異在南狼丘壁上造成凹凸不平的層面， 有的凸出層面可以形成長板凳，讓遊客坐着休息。由於這些砂岩的組成顆粒尺寸不同，它們的膠結程度亦不一樣[8]。有的砂岩很軟及脆弱[9][10][11]。
圖集
[編輯]
參考文獻
[編輯]- ^ Bureau of Land Management (October 24, 2014). "Paria Canyon-Vermilion Cliffs – Wilderness Management Plan". BLM Website. Archived from the original on January 20, 2016. Retrieved January 18, 2016.
- ^ VERLANDER, J.E. (1995), The Navajo Sandstone. Geology Today, 11: 143-146. https://doi.org/10.1111/j.1365-2451.1995.tb00943.x)
- ^ Bureau of Land Management. "Coyote Buttes Permit Area". BLM Website. Archived from the original on April 12, 2012. Retrieved April 6, 2012.
- ^ Bureau of Land Management. "BLM-AZ How to Obtain a Permit – Coyote Buttes Permit Area". BLM Website. Archived from the original on April 13, 2012. Retrieved April 6, 2012.
- ^ William E. Freeman, G. S. Visher; Stratigraphic analysis of the Navajo Sandstone. Journal of Sedimentary Research 1975;; 45 (3): 651–668. doi: https://doi.org/10.1306/212F6E06-2B24-11D7-8648000102C1865DWilliam E. Freeman, G. S. Visher; Stratigraphic analysis of the Navajo Sandstone. Journal of Sedimentary Research 1975;; 45 (3): 651–668. doi: https://doi.org/10.1306/212F6E06-2B24-11D7-8648000102C1865D)
- ^ Ralph E. Hunter, David M. Rubin（1983）Interpreting Cyclic Crossbedding, with An Example from the Navajo Sandstone, Editor(s): M.E. Brookfield, T.S. Ahlbrandt, Developments in Sedimentology, Elsevier,Volume 38,1983,Pages 429-454,ISSN 0070-4571,ISBN 9780444422330, https://doi.org/10.1016/S0070-4571(08)70808-2. (https://www.sciencedirect.com/science/article/pii/S0070457108708082)
- ^ John E. Marzolf(1983), Changing Wind and Hydrologic Regimes During Deposition of the Navajo and Aztec Sandstones, Jurassic (?), Southwestern United States.Editor(s): M.E. Brookfield, T.S. Ahlbrandt, Developments in Sedimentology,Elsevier,Volume 38,1983, Pages 635-660,ISSN 0070-4571,ISBN 9780444422330, https://doi.org/10.1016/S0070-4571(08)70816-1.(https://www.sciencedirect.com/science/article/pii/S0070457108708161) )
- ^ Schultz, R. A., C. H. Okubo, and H. Fossen (2010), Porosity and grain size controls on compaction band formation in Jurassic Navajo Sandstone, Geophys. Res. Lett., 37, L22306, doi:10.1029/2010GL044909. )
- ^ Seiler, W.M. (August 1, 2008). "Jurassic Navajo sandstone of Coyote Buttes, Utah/Arizona : coloration and diagenetic history, preservation of a dinosaur trample surface, and terrestrial analogs to Mars (unpublished M.S. thesis, Dept. of Geology and Geophysics, University of Utah, Salt Lake City, Utah)". none. Archived from the original on March 5, 2012.
- ^ Chan, M.A., and A.W. Archer (2000) Cyclic eolian stratification on the Jurassic Navajo Sandstone, Zion National Park: Periodicities and implications for paleoclimate. Archived April 21, 2016, at the Wayback Machine in D.A. Sprinkel, T.C. Chidsey, Jr., and P.B. Anderson, eds., pp. 607–18. Geology of Utah's Parks and Monuments.[dead link] Archived January 11, 2012, at the Wayback Machine Utah Geological Association, Salt Lake City, Utah.
- ^ Caputo, M.V. (2003) Geology of the Paria Canyon-Vermilion Cliffs Wilderness, Utah and Arizona. in D.A. Sprinkel, T.C. Chidsey Jr., and P.B. Anderson, eds., Geology of Utah's Parks and Monuments. Archived January 11, 2012, at the Wayback Machine Utah Geological Association, Salt Lake City, Utah.