Collapse of large complex impact craters: Implications from the Araguainha impact structure, central Brazil

Lana, Cristiano; Romano, Rafael; Reimold, Uwe; Hippertt, João Fernando Martins

doi:10.1130/g21952.1

Cited by 20 publications

(60 citation statements)

References 12 publications

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“…Petrographic studies by Engelhardt et al (1992) led to the conclusion that energy released upon the impact was sufficient to excavate a 2-2.5 km vertical section through the undeformed sediments of the Paraná Basin and part of the underlying crystalline basement rocks ( Fig. 2b) (see also, Lana et al 2006aLana et al , 2007. The excavation of the Paraná sediments affected an area with a radius of several kilometers and resulted in a 20-25 km wide cavity with a minimum depth of 2-2.5 km (Lana et al 2006a).…”

Section: Geology Of Araguainhamentioning

confidence: 99%

“…The Araguainha impact structure is the eroded remnant of the largest impact crater in South America (Crósta et al 1981;Theilen-Willige 1981;Engelhardt et al 1992;Lana et al 2006aLana et al , 2007. It is located in the northeastern part of the Paraná Basin (Fig.…”

Section: Geology Of Araguainhamentioning

confidence: 99%

“…Lana et al (2007) have demonstrated that the present morphology of the crater is largely controlled by the concentric arrangement of the structures and layered sedimentary units. However, while some structural data have been reported for some parts of the impact structure (Lana et al 2006a(Lana et al , 2007, no comprehensive structural analyses have been directed at understanding the geometry of the central uplift and the crater rim. In addition, the structural implications of the concentric ring features for the evolution of the impact crater have not been fully discussed.…”

Section: Introductionmentioning

confidence: 99%

“…However, the internal geometry of large (>25 km) impact structures remains a matter of contentious debate, as an increasing number of field-based mapping and geophysical experiments indicate that terrestrial craters of similar sizes may have distinct internal structures and morphologies (Jansa et al 1989;Tsikalas et al 1998aTsikalas et al , 1998bMorgan et al 2000;Dypvik and Jansa 2003;Grieve andTherriault 2000, 2004;Vermeesch and Morgan 2004;Wünnemann et al 2005). The structural variation between terrestrial craters seems to be a result of the distinct response of different target rocks (under distinct strain regimes and geothermal gradients) to the extreme pressure and temperatures released upon impact (Ivanov and Deutsch 1999;Lana et al 2003aLana et al , 2003bLana et al , 2006aLana et al , 2006bSpray et al 2004;Dence 2004;Collins et al 2004;Gibson and Reimold 2005;Riller 2005).…”

Section: Introductionmentioning

confidence: 99%

“…The 40 km wide Araguainha impact structure is a rare example of a shallowly eroded impact structure that provides an unparalleled opportunity to study the kinematics of complex crater formation ( Fig. 1) (Crósta et al 1981;Theilen-Willige 1981;Engelhardt et al 1992;Lana et al 2006aLana et al , 2007. Remote sensing analysis and stratigraphic correlations indicate that Araguainha preserves a fully exposed central peak, an annular basin and two main concentric ring features ( Fig.…”

Section: Introductionmentioning

confidence: 99%

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Structural evolution of the 40 km wide Araguainha impact structure, central Brazil

Lana

Filho

Marangoni

et al. 2008

Meteorit & Planetary Scien

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Abstract-The 40 km wide Araguainha structure in central Brazil is a shallowly eroded impact crater that presents unique insights into the final stages of complex crater formation. The dominant structural features preserved at Araguainha relate directly to the centripetal movement of the target rocks during the collapse of the transient cavity. Slumping of the transient cavity walls resulted in inward-verging inclined folds and a km-scale anticline in the outer ring of the structure. The folding stage was followed by radial and concentric faulting, with downward displacement of kilometer-scale blocks around the crater rim. The central uplift records evidence for km-scale upward movement of crystalline basement rocks from the transient cavity floor, and lateral moment of sedimentary target rocks detached from the cavity walls. Much of the structural grain in the central uplift relates to structural stacking of km-scale thrust sheets of sedimentary strata onto the core of crystalline basement rocks. Outward-plunging radial folds indicate tangential oblate shortening of the strata during the imbrication of the thrust sheets. Each individual sheet records an early stage of folding and thickening due to non-coaxial strains, shortly before sheet imbrication. We attribute this folding and thickening phase to the kilometer-scale inward movement of the target strata from the transient cavity walls to the central uplift. The outer parts of the central uplift record additional outward movement of the target rocks, possibly related to the collapse of the central uplift. An inner ring structure at 10-12 km from the crater center marks the extent of the deformation related to the outward movement of the target rocks.

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Section: Geology Of Araguainhamentioning

confidence: 99%

Section: Geology Of Araguainhamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Structural evolution of the 40 km wide Araguainha impact structure, central Brazil

Lana

Filho

Marangoni

et al. 2008

Meteorit & Planetary Scien

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Impact cratering: The South American record – Part 1

et al. 2019

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Magnetic fabric of Araguainha complex impact structure (Central Brazil): Implications for deformation mechanisms and central uplift formation

Yokoyama¹,

Trindade²,

Lana³

et al. 2012

Earth and Planetary Science Letters

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The weakening mechanisms involved in the collapse of complex impact craters are controversial. The Araguainha impact crater, in Brazil, exposes a complex structure of 40 km in diameter, and is an excellent object to address this issue. Its core is dominated by granite. In addition to microstructural observations, magnetic studies reveal its internal fabric acquired during the collapse phase. All granite samples exhibit impactrelated planar deformation features (PDFs) and planar fractures (PFs), which were overprinted by cataclasis. Cataclastic deformation has evolved from incipient brittle fracturing to the development of discrete shear bands in the center of the structure. Fracture planes are systematically decorated by tiny grains (b 10 μm) of magnetite and hematite, and the orientation of magnetic lineation and magnetic foliation obtained by the anisotropies of magnetic susceptibility (AMS) and anhysteretic remanence (AAR) are perfectly coaxial in all studied sites. Therefore, we could track the orientation of deformation features which are decorated by iron oxides using the AMS and AAR. The magnetic fabrics show a regular pattern at the borders of the central peak, with orientations consistent with the fabric of sediments at the crater's inner collar and complex in the center of the structure. Both the cataclastic flow revealed from microstructural observations and the structural pattern of the magnetic anisotropy match the predictions from numerical models of complex impact structures. The widespread occurrence of cataclasis in the central peak, and its orientations revealed by magnetic studies indicate that acoustic fluidization likely operates at all scales, including the mineral scales. The cataclastic flow made possible by acoustic fluidization results in an apparent plastic deformation at the macroscopic scale in the core.

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Collapse of large complex impact craters: Implications from the Araguainha impact structure, central Brazil

Cited by 20 publications

References 12 publications

Structural evolution of the 40 km wide Araguainha impact structure, central Brazil

Structural evolution of the 40 km wide Araguainha impact structure, central Brazil

Impact cratering: The South American record – Part 1

Magnetic fabric of Araguainha complex impact structure (Central Brazil): Implications for deformation mechanisms and central uplift formation

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