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Geoscience ›› 2019, Vol. 33 ›› Issue (05): 970-978.DOI: 10.19657/j.geoscience.1000-8527.2019.05.04

• Structural Geology and Stratigraphy • Previous Articles     Next Articles

Late Pleistocene Tectonic History of the Western Segment of Maniao-Puqian Fault: Evidence from the Laocheng Section, Northern Hainan Island

LI Wei1(), JIA Liyun2,3(), HU Daogong2,3, ZHANG Xujiao1, XIA Mengmeng2, LIN Wenjie1, YUAN Yue1   

  1. 1. School of Earth Sciences and Resources,China University of Geosciences,Beijing 100083,China
    2. Institute of Geomechanics,Chinese Academy of Geological Sciences,Beijing 100081,China
    3. Key Laboratory of Active Tectonics and Crustal Stability Assessment,Beijing 100081,China
  • Received:2019-04-16 Revised:2019-07-01 Online:2019-10-26 Published:2019-10-28
  • Contact: JIA Liyun

Abstract:

Maniao-Puqian Fault is an important seismogenic fault for the M7.5 Qiongshan earthquake in Hainan in 1605. Its tectonic history is of great significance for evaluating the crustal stability, earthquake risk mitigation, and the engineering of major construction projects such as the bridge connecting Hainan island and Leizhou peninsula. Geological and geomorphic studies show that the western segment of Maniao-Puqian Fault zone is about 2.5 km wide from north to south, and composed of three near-E-W-trending subparallel stepped normal faults. Fault profile excavation in Laocheng town exposed a wide (~70 m) N-S-trending fault zone, which reveals the fault tectonic history. Optically stimulated luminescence (OSL) dating results of the Daotang Formation indicate that the fault had experienced two tectonic events in 16-31 ka BP: an earlier N-/S-dipping normal faulting with a 3.3 m cumulative vertical displacement, followed by an intensive S-dipping normal faulting. Stratigraphic displacement in different ages indicates that the Maniao-Puqian Fault has been active since Pliocene, and its activity is strong in the Quaternary. It remains an important active fault in northern Hainan island.

Key words: Maniao-Puqian fault, Laocheng section, optically stimulated luminescence (OSL) dating, tectonic history

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