Rapid Pliocene uplift of Timor

Abstract

Palynology of exhumed Pliocene marine turbidites and marl beds on the island of Timor provide insights into crustal deformation in the Indonesian region. Between ca. 4.5 and ca. 3 Ma, palynomorphs were sourced primarily from Australia and New Guinea, with increasing swamp and mangrove elements sourced from an emerging proto-Timor. Following ca. 3.1 Ma, pollen and charcoal evidence track the rapid uplift of Timor to a high island, with the progressive appearance of montane and dry, lee-side fl oristic elements. Early-to mid-Pliocene uplift rates of 0.5-0.6 mm yr-1 increased to 2-5 mm yr-1 in the latest Pliocene. The rapid topographic development of Timor-Leste initiated earlier but followed a pattern similar to that of more westerly localities in the Timor sector of the Banda Arc. Timor's emergence from the marine environment is closely correlated with the timing of closure of the Indonesian seaway to deep-dwelling foraminfera.

Structural style in a young flexure-induced oblique extensional system, north-western Bonaparte Basin, Australia

“…Whilst this age for collision is older than some other estimates (3.5e2 Ma BP; Audley-Charles, 2004;Spakman and Hall, 2010), it is consistent with other evidence for a regional tectonic event at approximately 8 Ma BP from both Timor and the adjacent Australian North West Shelf (McCaffrey et al, 1985;Reed, 1985;Berry and McDougall, 1986;Richardson and Blundell, 1996;Rutherford et al, 2001;Keep et al, 2002;Harris, 2011;Duffy et al, 2013). Timor Island seems to have first emerged by~4.5 Ma BP (Nguyen et al, 2013), and uplift accelerated at~3 Ma BP (Quigley et al, 2012;Nguyen et al, 2013). At Present, the Australian plate is moving N20 E at rates of~77 mm yr À1 ( Fig.…”

“…De Keep and Harrowfield, 2008;Langhi et al, 2011;Bourget et al, 2012). It also coincides with the development of the Timor Trough and uplift of the Timor Island (Veevers et al, 1978;Keep et al, 2002;Haig, 2012;Nguyen et al, 2013), and suggests that the development of lithospheric flexure (Londoño and Lorenzo, 2004;Langhi et al, 2011) mainly controlled the Neogene-Recent deformation in this area. Flexure is capable of inducing extension in a convergent setting (Bradley and Kidd, 1991), and is widely accepted as the main deformation mechanism in the northern Bonaparte Basin (Etheridge et al, 1991;O'Brien et al, 1999;Keep et al, 2002;Londoño and Lorenzo, 2004;Keep et al, 2007;Langhi et al, 2011).…”

Resolving spatial heterogeneities in exhumation and surface uplift in Timor-Leste: Constraints on deformation processes in young orogens

“…From 12 to 41 m, the section exposes rhythmic alternations of chalks and marls, which may represent Milankovitch‐driven cyclicity, with the thickness of the cycles and the clay content increasing upward suggesting increase of sedimentation rate. From 41 m to the top of the section at 240 m, we find a succession of alternating clays, sandstones, and conglomerates [ Haig and McCartain , ; Nguyen et al , ]. This succession generally coarsens upward, with bedded sandstones and conglomerates becoming more common and clays becoming more contaminated with silt and sand upward.…”

Why mountains matter for biodiversity

“…Do evolutionary processes coincide with mountains uplift? When considering that uplift is counteracted by erosion (Antonelli, Kissling, et al, ; Molnar, ), mountains typically rise at about 1 mm/year (Graham, Parra, Mora, & Higuera, ), with extreme rates reported for Timor (c. 5 mm/year; Nguyen, Duffy, Shulmeister, & Quigley, ). But even though these rates sound slow from a human perspective, on a geological scale these processes can have a major impact on mountain taxa.…”