Biology of Amber-Producing Trees: Focus on Case Studies of <i>Hymenaea</i> and <i>Agathis</i>

Langenheim, Jean H.

doi:10.1021/bk-1995-0617.ch001

Cited by 70 publications

(75 citation statements)

References 88 publications

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“…It is well known that the amber resin includes both volatile and non-volatile fractions. 30 Most of the volatiles disappear during the aging process and the non-volatile parts (for example, acetogenins, fat and communic acid) become amber by free radical polymerization. Thermal analysis of different ambers, including Dominican amber, reported in the literature 31 indicates no mass loss at temperatures well above the maximum temperature of 175°C examined in the present investigation.…”

Section: Resultsmentioning

confidence: 99%

Using 20-million-year-old amber to test the super-Arrhenius behaviour of glass-forming systems

2013

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Fossil amber offers the opportunity to investigate the dynamics of glass-forming materials far below the nominal glass transition temperature. This is important in the context of classical theory, as well as some new theories that challenge the idea of an 'ideal' glass transition. Here we report results from calorimetric and stress relaxation experiments using a 20-millionyear-old Dominican amber. By performing the stress relaxation experiments in a step-wise fashion, we measured the relaxation time at each temperature and, above the fictive temperature of this 20-million-year-old glass, this is an upper bound to the equilibrium relaxation time. The results deviate dramatically from the expectation of classical theory and are consistent with some modern ideas, in which the diverging timescale signature of complex fluids disappears below the glass transition temperature.

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Section: Resultsmentioning

confidence: 99%

Using 20-million-year-old amber to test the super-Arrhenius behaviour of glass-forming systems

2013

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“…Strong bands at around 710 and 740 cm 1 (C-C vibrations) are typical in spectra of recent resins and decrease during the maturation process, which may be ascribed to damping of skeletal vibrations due to polymerization. 4,5,10,11,15 The copal from Madagascar is botanically assigned to Hymenaea sp. (Leguminosae).…”

Section: Resultsmentioning

confidence: 99%

A Raman spectroscopic approach to the maturation process of fossil resins

Winkler

Kirchner

Asenbaum

et al. 2001

J. Raman Spectrosc.

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Raman spectra of a range of differently aged samples of natural resins (recent resins, copals, fossils resins from Tertiary to Early Cretaceous age) were taken for a comparative study of the age‐induced maturation processes of the resins. It can be shown that a decrease in band intensity at around 1640 cm−1 due to loss of ν(CC) stretching vibrations, together with other spectral details, is correlated with the increase in age of the resins. Copyright © 2001 John Wiley & Sons, Ltd.

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“…Yet Mexican amber warrants study, particularly because it derives from the same angiospermous source trees as the coeval and more thoroughly investigated Dominican amber (early to middle Miocene, 15-20 Mya; Solórzano Kraemer, 2007Iturralde-Vinent and MacPhee 1996). Amber from both deposits is attributed to the Fabaceae genus Hymenaea (Poinar 1991;Langenheim 1995;Poinar and Brown 2002) and not to coniferous trees like most other ambers.…”

Section: Introductionmentioning

confidence: 99%

The first ptychanthoid Lejeuneaceae in Miocene Mexican amber

Scheben¹,

Schmidt²,

Shäfer-Verwimp³

et al. 2014

Telopea

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Two inclusions of leafy liverworts in Miocene Mexican amber are tentatively assigned to the extant genus Mastigolejeunea (Lejeuneaceae subfam. Ptychanthoideae). Both specimens share complicate bilobed leaves with a rounded lobe apex, a lobule with an oblique free margin continuing into the ventral margin of the leaf lobe, elongate leaf cells, a broad ventral merophyte, and undivided underleaves with a truncate to slightly emarginate, recurved apex. The lack of generative structures prevents a more thorough taxonomic treatment. Nevertheless, the inclusions represent the first ptychanthoid Lejeuneaceae from Mexican amber.

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Biology of Amber-Producing Trees: Focus on Case Studies of Hymenaea and Agathis

Cited by 70 publications

References 88 publications

Using 20-million-year-old amber to test the super-Arrhenius behaviour of glass-forming systems

Using 20-million-year-old amber to test the super-Arrhenius behaviour of glass-forming systems

A Raman spectroscopic approach to the maturation process of fossil resins

The first ptychanthoid Lejeuneaceae in Miocene Mexican amber

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