首页|3-dimensional trapdoor structure of laccolith-induced doming and implications for laccolith emplacement, Pampa Amarilla, Mendoza Province, Argentina

3-dimensional trapdoor structure of laccolith-induced doming and implications for laccolith emplacement, Pampa Amarilla, Mendoza Province, Argentina

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  • NSTL
  • Elsevier
Laccolith emplacement and growth are controlled by doming of overburden rocks. Understanding the mechanics and structural evolution of laccolith-induced doming is therefore essential for revealing the emplacement dynamics and growth of laccoliths. In this paper, we present a 3D reconstruction of a subsurface laccolithic intrusion through the structural reconstruction of a well-exposed dome at Pampa Amarilla, Neuquen Basin, southern Mendoza province, Argentina. The 3D reconstruction was made possible by the unique integration of surface geological data and subsurface 3D seismic and borehole data. We estimate that the Pampa Amarilla laccolith is similar to 400 m thick, similar to 3 km and 2 km long in the E-W and N-S directions, respectively. Along an E-W cross section, the laccolith exhibits a wedge shape with maximum thickness near its western edge and gradual thinning toward the east. The structure of the dome is typical of a trapdoor, with faulting along the western, northwestern and southwestern edges, and tilting of the overburden to the east. The trapdoor tilting of the laccolith's overburden was the main mechanism controlling the thickening and growth of the Pampa Amarilla laccolith, which exhibits a relatively high thickness-to-length ratio T/D similar to 0.13. Numerous laccolithic intrusions exhibit similar values of T/D, and our study suggests that faulting commonly controls emplacement of laccoliths with T/D > 0.1; conversely, our study suggests that the established mechanical models of laccolith emplacement based on elastic bending of the overburden applies only to thin laccoliths. Finally, our study highlights the necessity and value of integrating field geological measurements with subsurface 3D seismic and borehole data for structural reconstructions of subsurface laccolith intrusions.

Laccolith3-dimensional domeTrapdoor structurePunched laccolithSurface-subsurface data integrationPAYENIA VOLCANIC PROVINCENORTHERN NEUQUEN BASINRIO-GRANDE VALLEYTORRES-DEL-PAINEHENRY MOUNTAINSTHRUST BELTIGNEOUS INTRUSIONSPETROLEUM SYSTEMSSILL EMPLACEMENTSOUTHERN MENDOZA

Galland, Olivier、de la Cal, Hernan、Mescua, Jose、Rabbel, Ole

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Univ Oslo

ROCH SA

Consejo Nacl Invest Cient & Tecn

2022

10.1016/j.tecto.2022.229418

Tectonophysics

Tectonophysics

EISCI
ISSN：0040-1951
年,卷(期)：2022.836
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