Evolutionary cycles during the Andean orogeny:: repeated slab breakoff and flat subduction?

被引:117
作者
Haschke, MR
Scheuber, E
Günther, A
Reutter, KJ
机构
[1] Tel Aviv Univ, Dept Geophys & Planetary Sci, IL-69978 Tel Aviv, Israel
[2] Free Univ Berlin, Inst Geol Geophys & Geoinfomat, D-12249 Berlin, Germany
关键词
D O I
10.1046/j.1365-3121.2002.00387.x
中图分类号
P [天文学、地球科学];
学科分类号
07 ;
摘要
Tectonomagmatic similarities between the modern Chilean flat-slab region and pre-Neogene magmatic episodes suggest that they represent analogues to flat subduction. Evolutionary patterns in each magmatic suite include (i) increasing La/Yb ratios and Sr-and Nd-isotopic enrichment through time, (ii) eastward-migration of magmatism after periods of transpressional/transtensional intra-arc deformation, and (iii) subsequent termination and virtual absence of main-arc activity for 5-10 Myr. These patterns may reflect slab shallowing followed by flat subduction and thickening of the overlying crust. if repeated, they require interchanging episodes of slab steepening. Increasing convergence rates force slab kinking and eventual failure of the oversteepened slab, followed by rebound of the slab tip (owing to lack of further slab pull), flat subduction and termination of subduction-related magmatism. Rapid subduction leads to shallow overriding of the detached slab fragment. Eclogitization of the gradually steepening slab tip at depth and subsequent slab pull permits asthenospheric corner flow and subduction-related magmatism.
引用
收藏
页码:49 / 55
页数:7
相关论文
共 39 条
  • [1] BARAZANGI M, 1976, GEOLOGY, V4, P686, DOI 10.1130/0091-7613(1976)4<686:SDOEAS>2.0.CO
  • [2] 2
  • [3] SEISMICITY AND SHAPE OF THE SUBDUCTED NAZCA PLATE
    CAHILL, T
    ISACKS, BL
    [J]. JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH, 1992, 97 (B12) : 17503 - 17529
  • [4] CHARRIER R, 1994, TECTONICS SO CENTRAL, P189
  • [5] TECTONIC AND MAGMATIC EVOLUTION OF THE ANDES OF NORTHERN ARGENTINA AND CHILE
    COIRA, B
    DAVIDSON, J
    MPODOZIS, C
    RAMOS, V
    [J]. EARTH-SCIENCE REVIEWS, 1982, 18 (3-4) : 303 - 332
  • [6] Coira B., 1993, INT GEOL REV, V35, P677, DOI DOI 10.1080/00206819309465552
  • [7] THE ORIGIN AND EVOLUTION OF MAGMAS FROM THE SAN-PEDRO-PELLADO VOLCANIC COMPLEX, S CHILE - MULTICOMPONENT SOURCES AND OPEN SYSTEM EVOLUTION
    DAVIDSON, JP
    FERGUSON, KM
    COLUCCI, MT
    DUNGAN, MA
    [J]. CONTRIBUTIONS TO MINERALOGY AND PETROLOGY, 1988, 100 (04) : 429 - 445
  • [8] G┬u┬anther A., 1998, TERRA NOSTRA, V5, P58
  • [9] Gutscher MA, 2000, GEOLOGY, V28, P535, DOI 10.1130/0091-7613(2000)028<0535:CSMBCB>2.3.CO
  • [10] 2