1 Ductile and brittle deformation in Singapore: a record of Mesozoic orogeny and 2 amalgamation in Sundaland, and of post-orogenic faulting 3 4 A. Graham Leslie*1, Thomas J.H. Dodd1, Martin R. Gillespie1, Rhian S. Kendall2, Thomas P. 5 Bide3, Timothy I. Kearsey1, Marcus R. Dobbs3, Michael Kim Woon Lee4, and Kiefer Chiam5 6 7 1British Geological Survey, Lyell Centre, Research Avenue South, Edinburgh, EH14 4AP, United Kingdom. 8 2British Geological Survey, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, United Kingdom. 9 3British Geological Survey, Environmental Science Centre, Keyworth, Nottingham, NG12 5GG, United Kingdom. 10 4Neptune Court, 8 Marine Vista #15-33, Singapore 449032. 11 5BCA Academy, 200 Braddell Rd, Singapore 579700 12 *(Corresponding author e:mail:
[email protected]) 13 14 Keywords: Singapore, Mesozoic, orogeny, fold and thrust tectonics, faulting. 15 16 Abstract: Singapore bedrock geology is dominated by late Permian to Triassic arc magmatism and 17 a genetically related, essentially Middle to Upper Triassic, marine to fluvial volcano-sedimentary 18 inner forearc succession. These Mesozoic strata are deformed into a pattern of NE-translated 19 ductile–brittle deformation structures during the latest Triassic to earliest Jurassic collision and 20 amalgamation of the Sibumasu continental block with the southern part of the Sukhothai Arc. The 21 subduction-related magmatic complex represented in Singapore by the granitic to gabbroic plutons 22 of the Bukit Timah Centre likely acted as a backstop to thrusting at this time. Collisional tectonics 23 drove progressive shortening and steepened earlier-formed inclined asymmetrical folds, 24 culminating in the regional-scale development of a non-coaxial, NE-vergent and NE-facing, fold 25 and thrust system.