Melange versus fore-arc contributions to sedimentation and uplift, during rapid denudation of a young Banda fore-arc/continent collisional belt

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doi: 10.1016/j.jseaes.2017.02.008
Author(s): Duffy, Brendan; Kalansky, Julie; Bassett, Kari; Harris, Ron; Quigley, Mark; van Hinsbergen, Douwe J. J.; Strachan, Lorna J.; Rosenthal, Yair
Author Affiliation(s): Primary:
University of Melbourne, School of Earth Sciences, Australia
Other:
University of Canterbury, New Zealand
Scripps Institution of Oceanography, United States
Rutgers Institute of Marine and Coastal Sciences, United States
Brigham Young University, United States
Utrecht University, Netherlands
University of Auckland, New Zealand
Volume Title: Journal of Asian Earth Sciences
Source: Journal of Asian Earth Sciences, Vol.138, p.186-210. Publisher: Elsevier, Oxford, United Kingdom. ISSN: 1367-9120
Note: In English. Includes appendices. 156 refs.; illus., incl. geol. sketch map
Summary: New sedimentary geochemistry and petrographic analyses provide the most extensive sedimentary documentation yet of the rapid denudation of the young Timor orogen. The data from three basins including two widely-separated, well-dated sections of the Synorogenic Megasequence of Timor-Leste, and a re-dated DSDP 262, constrain the source and timing of detrital sediment flux during forearc-continent collision along the Timor sector of the Banda Arc. The exhumed synorogenic piggy-back basins formed above a mélange unit that developed at the expense of a weak stratigraphic horizon in the Mesozoic stratigraphy, and was exhumed to the sea floor in latest Messinian time. Following an interval of deep marine chalky marl sedimentation, an increasingly muddy sediment flux indicates that the island of Timor became emergent and shed sediment by 4.5 Ma. Comparison of exhumed sections with similar patterns in the DSDP262 chemistry suggests that the sediment source was probably located some 50-60 km distant from the basin, which is consistent with the Aileu region of Timor-Leste that shows an appropriate exhumation history. All sedimentation between 4.5 and 3.2 Ma was probably derived from a low-relief, rapidly eroding, and mudstone-dominated landscape with geochemical affinities to the Triassic-mudstone-derived synorogenic mélange. The mélange unit overlies and surrounds the Banda Terrane, and was presumably structurally emplaced by propagation of a decollement through the Triassic rocks during the collision. After 3.2 Ma, sedimentation was dominated by hard rock lithologies of the Banda Terrane, consisting of forearc cover and basement, the latter including elements of metamafic rocks and metapelites. This phase of sedimentation was accompanied by rapid uplift, which may have been partly driven by a transient imbalance between rock uplift and denudation as resistant lithologies emerged from below mélange-like mudstone. Previous work has suggested that the timing of collision in Timor-Leste and West Timor was substantially different. Our reevaluation of DSDP 262 facies migration history in the context of the re-dating presented here, favours a relatively synchronous onset of uplift in both halves of the island, but with different partitioning of strain between the foreland and hinterland in each half of the island.
Year of Publication: 2017
Research Program: DSDP Deep Sea Drilling Project
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; 18 Geophysics, Solid-Earth; Absolute age; Asia; Banda Arc; Basin analysis; Basins; Batu Putih Formation; Baucau Limestone; Cenozoic; Continental lithosphere; DSDP Site 262; Dates; Deep Sea Drilling Project; Dilor Conglomerate; East Timor; Exhumation; Far East; Faults; Foraminifera; Fore-arc basins; Geochemistry; Globigerinacea; Globorotalia; Globorotaliidae; Indian Ocean; Lari Guti Formation; Leg 27; Lesser Sunda Islands; Lithosphere; Lithostratigraphy; Major elements; Malay Archipelago; Marine sedimentation; Melange; Messinian; Metals; Microfossils; Miocene; Neogene; Overthrust faults; Pacific Ocean; Plate collision; Plate tectonics; Provenance; Reworking; Rotaliina; Sedimentary petrology; Sedimentation; Sedimentology; Sm/Nd; Tertiary; Timor; Timor Sea; Timor Trough; Uplifts; Upper Miocene; Viqueque Formation; West Pacific
Coordinates: S105200 S105200 E1235100 E1235100
Record ID: 2019065899
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands