Analogue models of laccolith formation

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doi: 10.1016/0191-8141(95)00012-3
Authors:Roman-Berdiel, Teresa; Gapais, D.; Brun, J. P.
Author Affiliations:Primary:
Université de Rennes I, Géosciences Rennes, Rennes, France
Volume Title:Journal of Structural Geology
Source:Journal of Structural Geology, 17(9), p.1337-1346. Publisher: Pergamon, Oxford-New York, International. ISSN: 0191-8141
Publication Date:1995
Note:In English. 43 refs.; illus., incl. block diag., 2 plates, 3 tables, sects.
Summary:Dynamically scaled analogue models of laccolithic intrusions are described. Experiments consisted of the injection of a Newtonian fluid (flow-viscosity putty) into a sandpack, with or without an interbedded ductile layer of silicone putty acting as a potential decollement level. Boundary conditions were chosen to analyse the influence of the thickness of the brittle cover and of the decollement layer on the pattern of intrusion. Further experiments were made to examine the effects of an extensional regime during intrusion. The experimental results showed that: 1) laccolith formation required the occurrence of a decollement layer between two competent units, 2) the critical thickness of the decollement layer necessary for laccolith formation decreases with increasing depth, 3) laccoliths change from lenses to bell-shaped with decreasing overburden, 4) for a constant thickness of decollement layer, the largest diameter of laccoliths is proportional to the thickness of the overburden and 5) a syn-injection gravitational sliding regime results in an asymmetric batholith, with amplification of the bell shape. [R.A.H.]
Subjects:Clastic sediments; Decollement; Deformation; Depth; Ductile deformation; Effects; Emplacement; Experimental studies; Extension tectonics; Gravity sliding; Intrusions; Kinematics; Laccoliths; Layered materials; Mathematical models; Models; Overburden; Physical models; Plutons; Sand; Sediments; Tectonics; Tethys; Thickness; Viscosity; Asia; Himalayas; Manaslu Granite; Manaslu Laccolith
Abstract Numbers:96M/974
Record ID:1995064414
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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100 1 |a Roman-Berdiel, Teresa  |e analytic author  |u Université de Rennes I, Géosciences Rennes, Rennes 
245 1 0 |a Analogue models of laccolith formation 
300 |a p. 1337-1346 
500 |a In English. 43 refs. 
500 |a Abstract number: 96M/974 
500 |a Abstractor: R.A.H. 
500 |a Affiliation: Université de Rennes I, Géosciences Rennes; Rennes; FRA; France 
500 |a Key title: Journal of Structural Geology 
500 |a Source note: Journal of Structural Geology, 17(9), p.1337-1346. Publisher: Pergamon, Oxford-New York, International. ISSN: 0191-8141 
500 |a Publication type: journal article 
504 |b 43 refs. 
510 3 |a GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom 
520 |a Dynamically scaled analogue models of laccolithic intrusions are described. Experiments consisted of the injection of a Newtonian fluid (flow-viscosity putty) into a sandpack, with or without an interbedded ductile layer of silicone putty acting as a potential decollement level. Boundary conditions were chosen to analyse the influence of the thickness of the brittle cover and of the decollement layer on the pattern of intrusion. Further experiments were made to examine the effects of an extensional regime during intrusion. The experimental results showed that: 1) laccolith formation required the occurrence of a decollement layer between two competent units, 2) the critical thickness of the decollement layer necessary for laccolith formation decreases with increasing depth, 3) laccoliths change from lenses to bell-shaped with decreasing overburden, 4) for a constant thickness of decollement layer, the largest diameter of laccoliths is proportional to the thickness of the overburden and 5) a syn-injection gravitational sliding regime results in an asymmetric batholith, with amplification of the bell shape. 
650 7 |a Clastic sediments  |2 georeft 
650 7 |a Decollement  |2 georeft 
650 7 |a Deformation  |2 georeft 
650 7 |a Depth  |2 georeft 
650 7 |a Ductile deformation  |2 georeft 
650 7 |a Effects  |2 georeft 
650 7 |a Emplacement  |2 georeft 
650 7 |a Experimental studies  |2 georeft 
650 7 |a Extension tectonics  |2 georeft 
650 7 |a Gravity sliding  |2 georeft 
650 7 |a Intrusions  |2 georeft 
650 7 |a Kinematics  |2 georeft 
650 7 |a Laccoliths  |2 georeft 
650 7 |a Layered materials  |2 georeft 
650 7 |a Mathematical models  |2 georeft 
650 7 |a Models  |2 georeft 
650 7 |a Overburden  |2 georeft 
650 7 |a Physical models  |2 georeft 
650 7 |a Plutons  |2 georeft 
650 7 |a Sand  |2 georeft 
650 7 |a Sediments  |2 georeft 
650 7 |a Tectonics  |2 georeft 
650 7 |a Tethys  |2 georeft 
650 7 |a Thickness  |2 georeft 
650 7 |a Viscosity  |2 georeft 
651 7 |a Asia  |2 georeft 
651 7 |a Himalayas  |2 georeft 
653 |a Manaslu Granite 
653 |a Manaslu Laccolith 
700 1 |a Gapais, D.,  |e analytic author 
700 1 |a Brun, J. P.,  |e analytic author 
773 0 |t Journal of Structural Geology  |d Oxford-New York : Pergamon, Sep. 1995  |x 0191-8141  |y JSGEDY  |n Journal of Structural Geology, 17(9), p.1337-1346. Publisher: Pergamon, Oxford-New York, International. ISSN: 0191-8141 Publication type: journal article  |g Vol. 17, no. 9  |h illus., incl. block diag., 2 plates, 3 tables, sects. 
856 |u urn:doi: 10.1016/0191-8141(95)00012-3