气候变化领域集成服务门户(CCPortal): The Bruneian record of “Borneo Amber”: A regional review of fossil tree resins in the Indo-Australian Archipelago

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DOI	10.1016/j.earscirev.2019.103005
	The Bruneian record of “Borneo Amber”: A regional review of fossil tree resins in the Indo-Australian Archipelago
	Kocsis L.; Usman A.; Jourdan A.-L.; Hassan S.H.; Jumat N.; Daud D.; Briguglio A.; Slik F.; Rinyu L.; Futó I.
发表日期	2020
ISSN	00128252
卷号	201
英文摘要	In this study we intend to provide an overview on fossilized tree resins (amber) commonly found in Southeast Asia, more particularly in the Indo-Australian Archipelago (IAA). These remains are often referred in literature as “Indonesian amber”, “Borneo amber” or simply as “dammar”. They are very common in the region and the Brunei Sultanate is no exception as most of its Neogene sedimentary successions contain amber-rich layers. Although amber is a common fossil in the country and in northern Borneo, to our knowledge it has not been studied in great detail so far. Here we present an account on the “Borneo Ambers” from Brunei, regarding their stratigraphic origin, basic physical properties, their interaction with the biosphere and their botanical origin using Fourier-transform infrared spectroscopy (FTIR). Additionally, a number of ambers and modern tree resins were analysed for their carbon isotope composition and a few were tested with gas chromatography. We discuss the results in a regional and global context, in comparison with available data from the IAA. The ambers come from four different lithostratigraphic units with an age range of 12 to 3 million years (middle Miocene to Pliocene). Recently reworked ambers from the coast, ambers from younger alluvial deposits, and several modern tree resins from Dipterocarpaceae and Araucariaceae (Agathis borneensis) were also included in the study. The >60 FTIR analyses of modern and fossil specimens suggest that all the Brunei ambers were produced by trees of Dipterocarpaceae. There is no indication of Agathis in the fossil record, in agreement with their lower abundance in the forests of Borneo. Modern and fossil dipterocarp resins were found to be different based on the following criteria: (1) Different reactions to solubility, hot needle and UV tests with faster reaction time and less fluorescence for the modern ones; (2) Clear distinction based on certain FTIR absorbance band ratios, mostly by those that represent carboxylic acids and esters (e.g., ~1700 and 1243 cm-1); (3) Modern resin yielded on an average 3‰ lower δ13C values, (4) Gas chromatography data reflect maturation differences among the samples. Although there is some overlap in the chemical results between the two groups, generally all these differences reflect different maturation stages of the resinous material and point towards loss of low δ13C components from the organic structure of the resin. The minor timewise decreasing trend in average δ13C from the late middle Miocene to late Miocene can be explained by (1) gradual changes in local environmental conditions, and/or (2) increased amount of less mature specimens among the younger samples. In contrast, the highest obtained δ13C values were found in the youngest Pliocene ambers. Instead of maturation bias this can be linked to environmental factors such as cooler-drier climate with increased seasonality, probably reflecting the onset of the northern hemisphere glaciation. © 2019 Elsevier B.V.
关键词	Agathis Amber Dipterocarp Infrared spectroscopy Organic carbon isotopes Resin
英文关键词	amber; carbon isotope; environmental factor; fossil record; isotopic composition; lithostratigraphy; maturation; organic carbon; tree; Borneo; Brunei Darussalam; Agathis (conifer); Agathis borneensis; Araucariaceae; Dipterocarpaceae
语种	英语
来源期刊	Earth Science Reviews
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/203758
作者单位	Geology Group, Faculty of Science, Universiti Brunei Darussalam, Jalan Tungku Link, Gadong, BE1410, Brunei Darussalam; Chemistry Department, Faculty of Science, Universiti Brunei Darussalam, Jalan Tungku Link, Gadong, BE1410, Brunei Darussalam; Bloomsbury Environmental Isotope Facility, University College London, Gower Street, London, WC1E 6BT, United Kingdom; DI.S.T.A.V, Dipartimento di Scienze della Terra, dell'Ambiente e della Vita Università degli Studi di Genova, Corso Europa, 26, Genova, I – 16132, Italy; Environmental and Life Sciences Department, Faculty of Science, Universiti Brunei Darussalam, Jalan Tungku Link, Gadong, BE1410, Brunei Darussalam; Isotope Climatology and Environmental Research Centre (ICER), Institute for Nuclear Research, Hungarian Academy of Sciences, Debrecen, Hungary
推荐引用方式 GB/T 7714	Kocsis L.,Usman A.,Jourdan A.-L.,等. The Bruneian record of “Borneo Amber”: A regional review of fossil tree resins in the Indo-Australian Archipelago[J],2020,201.
APA	Kocsis L..,Usman A..,Jourdan A.-L..,Hassan S.H..,Jumat N..,...&Futó I..(2020).The Bruneian record of “Borneo Amber”: A regional review of fossil tree resins in the Indo-Australian Archipelago.Earth Science Reviews,201.
MLA	Kocsis L.,et al."The Bruneian record of “Borneo Amber”: A regional review of fossil tree resins in the Indo-Australian Archipelago".Earth Science Reviews 201(2020).