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Please use this identifier to cite or link to this item: http://apo.ansto.gov.au/dspace/handle/10238/2611

Title: Stratigraphy and sedimentology of the longest terrestrial record in NE-Australia: Lynch’s Crater.
Authors: Wust, R
Kershaw, P
Rieser, U
Jacobsen, GE
Deino, A
Keywords: Stratigraphy
Australia
Sedimentation
Craters
Volcanic Rocks
Peat
Issue Date: Jul-2007
Publisher: Elsevier
Citation: Wust, R., Kershaw, P., Rieser, U., Jacobsen, G. E., & Deino, A. (2007). Stratigraphy and sedimentology of the longest terrestrial record in NE-Australia: Lynch’s Crater. International Union for Quaternary Research XVII Congress (INQUA) – “The Tropics: Heat Engine of the Quaternary”, 28th July – 3rd August 2007. Cairns, Australia: Cairns Convention Centre. In Quaternary International, 167-168, 456.
Abstract: Lynch’s Crater on the Atherton Tablelands in NE-Australia, formed some >200,000 years ago during an explosive eruption of basaltic material creating a maar more than 80 m deep. The crater walls are highly weathered and are blanketed by thick (>2 m) sequences of laterites that contain slates and other metasedimentary rocks (up to boulder size) and various types of volcanic rock fragments. Since the eruption, the maar has been filled with lake sediments that are topped by peat material and the recovered core was 64 m long. The basal sediments below 62.75 m are composed of massive grey silty-sandy clays with abundant rock fragments including basalts, vein quartz and other quartz-rich metasediments. The subsequent 50 m thick lake sediments are composed of massive and laminated sediments. The bottom lake sediments have frequent thick (up to > 2 cm) turbidite sequences while the top sediments have only few thin (max few mm) clay-rich turbidite deposits. Beside the turbidite layers, the lake sediments are either massive or laminated. Most of the sediments in particular in the upper 30 m are laminated. The varves are chemical varves with various colours from dark green, dark blue (vivianite) to black. The top 13–16 m (depending on the location in the crater) are composed of mainly minerotrophic peats and represent the past 60 ka. Geochemical analysis shows that Heinrich and Dangaard-Oeschger events can be detected. Here we present in detail stratigraphic and geochemical changes and present evidence for environmental changes of the entire core. The geochronology is based on C14 AMS, OSL and Ar-Ar dates.
URI: http://apo.ansto.gov.au/dspace/handle/10238/2611
ISSN: 1040-6182
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