東非造山運動
東非造山運動 (EAO)是東西兩塊岡瓦納大陸(澳洲–印度–南極洲與非洲–南美)沿莫桑比克帶於新元古代拼合的主要階段。[2]:320–321, 324
岡瓦納大陸的拼合
1980年代早期，麥克威廉姆斯首先提出了岡瓦納大陸在晚前寒武紀期間由兩個更古老的碎塊沿泛非洲莫桑比克帶拼合而來。[3]十年後，這次合併被命名為東非造山運動，不過人們也同時認識到它的過程遠比原來所想要複雜。先是幾個零碎的曾組成羅迪尼亞超大陸的克拉通互相拼合，接着才是兩大塊陸地互相拼合，形成相對短命的岡瓦納超大陸。[2]
關於這次合併，有兩個假說。[4]其一，EAO從島弧合併為主的增生運動在新元古代發展為碰撞造山運動，同時阿扎尼亞與剛果-坦桑尼亞-班韋烏盧板塊於約640Ma相撞。[5]其二，約750-530Ma的東岡瓦納拼合過程分多個階段，可將東非造山運動分為兩個主要時期：早些的EAO(約750-620Ma)和更晚的庫嘎造山運動(約570-530Ma)。[6]在前者發生時，後者體現為兩個同時發生的事件：分別是印度和澳-東南極、印度-阿扎尼亞的碰撞。另外，後一種情況的兩個造山帶在馬達加斯加相交，是阿扎尼亞-印度碰撞的理論位置，庫嘎造山運動的這一部分應被重新命名為馬達加斯加造山運動。[7]:256–257
侵蝕與寒武紀大爆發
東非造山運動最終形成了跨岡瓦納山脈，有超過8000km長、1000km寬。這山系的沉積區也被稱為岡瓦納扇，在美國以約10km厚的沉積物覆蓋了100000km2。沉積過程持續了超過2.6億年，約550Ma的寒武紀大爆發就在這時發生。這些空前的沉積可能為早期動物的多樣化提供了物質基礎。[8]
造山帶受到的侵蝕猛烈到到奧陶紀就變成了埃塞俄比亞的夷平面。[9]:33–64[10]:287–296
新生代
新生代東非裂谷主要從東非的元古代裂谷前系統所遺留的複雜模式演化而來。[11]:325它穿過坦桑尼亞克拉通東部的莫桑比克帶。[12]:106–108
參考
- ^ Meert 2003
- ^ 2.0 2.1 Stern 1994
- ^ McWilliams 1981，Abstract
- ^ For a discussion see Meert 2003，Discussion, p. 31; Collins & Pisarevsky 2005，Comparisons with other models, pp. 256–257; Meert & Lieberman 2008，Assembling Gondwana: polyphase or simple?, pp. 9–11; Nance, Murphy & Santosh 2014，Pannotia (Gondwana), pp. 12, 14
- ^ Azania was defined by Collins & Windley 2002，Discussion, pp. 334–335 and named by Collins & Pisarevsky 2005，第244頁
- ^ Meert 2003，Abstract
- ^ Collins & Pisarevsky 2005，Comparisons with other models
- ^ Squire et al. 2006，Abstract
- ^ Abbate, Ernesto; Bruni, Piero; Sagri, Mario. Geology of Ethiopia: A Review and Geomorphological Perspectives. Billi, Paolo (編). Landscapes and Landforms of Ethiopia. World Geomorphological Landscapes. 2015. ISBN 978-94-017-8026-1. doi:10.1007/978-94-017-8026-1_2.
- ^ Coltorti, M.; Dramis, F.; Ollier, C.D. Planation surfaces in Northern Ethiopia. Geomorphology. 2007, 89 (3–4). doi:10.1016/j.geomorph.2006.12.007.
- ^ Ring 1994，Conclusions
- ^ Aulbach, Rudnick & McDonough 2011，Geology and samples
資料
- Aulbach, S.; Rudnick, R. L.; McDonough, W. F. Evolution of the lithospheric mantle beneath the East African Rift in Tanzania and its potential signatures in rift magmas 478. 2011: 105–125 [6 January 2018]. ISBN 978-0-8137-2478-2. doi:10.1130/2011.2478(06).
|journal=被忽略 (幫助) - Collins, A. S.; Pisarevsky, S. A. Amalgamating eastern Gondwana: The evolution of the Circum-Indian Orogens. Earth-Science Reviews. 2005, 71 (3–4): 229–270. Bibcode:2005ESRv...71..229C. CiteSeerX 10.1.1.558.5911
. doi:10.1016/j.earscirev.2005.02.004. - Collins, A. S.; Windley, B. F. The tectonic evolution of central and northern Madagascar and its place in the final assembly of Gondwana (PDF). The Journal of Geology. 2002, 110 (3): 325–339 [6 January 2018]. Bibcode:2002JG....110..325C. doi:10.1086/339535. hdl:2440/34282 .
- McWilliams, M. O. Palaeomagnetism and Precambrian tectonic evolution of Gondwana 4. 1981: 649–687. ISBN 9780444419101. doi:10.1016/S0166-2635(08)70031-8.
|journal=被忽略 (幫助) - Meert, J. G. A synopsis of events related to the assembly of eastern Gondwana (PDF). Tectonophysics. 2003, 362 (1): 1–40 [6 January 2018]. Bibcode:2003Tectp.362....1M. doi:10.1016/S0040-1951(02)00629-7.
- Meert, J. G.; Lieberman, B. S. The Neoproterozoic assembly of Gondwana and its relationship to the Ediacaran–Cambrian radiation. Gondwana Research. 2008, 14 (1): 5–21. Bibcode:2008GondR..14....5M. S2CID 2814283. doi:10.1016/j.gr.2007.06.007.
- Nance, R. D.; Murphy, J. B.; Santosh, M. The supercontinent cycle: a retrospective essay. Gondwana Research. 2014, 25 (1): 4–29. Bibcode:2014GondR..25....4N. doi:10.1016/j.gr.2012.12.026.
- Ring, U. The influence of preexisting structure on the evolution of the Cenozoic Malawi rift (East African rift system). Tectonics. 1994, 13 (2): 313–326 [6 January 2018]. Bibcode:1994Tecto..13..313R. doi:10.1029/93TC03188.
- Squire, R. J.; Campbell, I. H.; Allen, C. M.; Wilson, C. J. Did the Transgondwanan Supermountain trigger the explosive radiation of animals on Earth? (PDF). Earth and Planetary Science Letters. 2006, 250 (1): 116–133 [11 September 2017]. Bibcode:2006E&PSL.250..116S. doi:10.1016/j.epsl.2006.07.032.
- Stern, R. J. Arc assembly and continental collision in the Neoproterozoic East African Orogen: implications for the consolidation of Gondwanaland (PDF). Annual Review of Earth and Planetary Sciences. 1994, 22 (1): 319–351 [6 January 2018]. Bibcode:1994AREPS..22..319S. doi:10.1146/annurev.ea.22.050194.001535.
