The role of backstop shape during inversion tectonics physical models

Anais da Academia Brasileira de Ciências

Caroline J.s. Gomes¹  André Danderfer Filho¹  Ana Maria A. Posada¹  Anielle C. Da Silva¹ 

[1] ,Universidade Federal de Ouro Preto Escola de Minas Departamento de GeologiaOuro Preto MG ,Brasil

关键词: analogue models;    backstop geometry;    buttress effect;    inversion tectonics;    normal detachment reactivation;    modelos analógicos;    geometria do anteparo;    efeito obstáculo;    tectônica de inversão;    reativação do descolamento basal;   

DOI  :  10.1590/S0001-37652010000400021

来源: SciELO

【 摘 要 】

The style of deformation of rocks from basin-infilling sequences in positively inverted natural basins was discussed upon the results of laboratory experiments carried out in sandboxes with sand packs laid down in the space between two wooden blocks. The space simulated stages of crustal extension leading to (1) a half graben due to extension above a listric extensional detachment, with the blocks simulating the footwall and hanging wall, or (2) a graben, with the blocks simulating the external margins that drifted apart above a horizontal detachment. Combinations of two different angles were used to simulate the dip of curved normal faults along the internal face of the wooden blocks. Backstops in the half graben had a convex up internal face. Backstops in the graben had a concave up internal face. Shortening as partitioned in forward and backward movements within the sand packs, and the kinematics of contraction was largely influenced by the convex or concave internal faces. A buttress effect characterized by rotation of the sand pack close to the footwall was stronger for footwall with steeper-dipping internal faces. The results were compared to other physical experiments and applied to an inverted basin found in nature.

【 授权许可】

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