Amber cretaceous

Lambert, J. B., S. C. Johnson, and G. O. Poinar, Jr. (1996), Nuclear magnetic resonance sediment characterization of cretaceous amber, Archaeometry 38, 325-335. 

Waggoner, B. M. (1994). Fossil micro-organisms from upper Cretaceous amber of Mississippi. Review of Palaeohotany and Palynology, 80, 75-84. 

Hibbett DS, Grimaldi D, Donoghue MJ Fossil mushrooms from Miocene and Cretaceous ambers and the evolution of homobasidiomycetes. Am J Bot 1997 84 981-991. 

Possibly, as presumed by Frausto Da Silva and Williams (2001), some hitherto essential elements lost their biocatalytic functions altogether or are about to do so (ibid.) yet, this issue is open to speculations only because there is no way to determine former biocatalytic functions in fossil samples even if they are fully preserved, like inclusions in amber (with chitin retaining the metals) or dry mummies. Moreover, very few such samples date back beyond the Cretaceous (dinosaur xeromummies from Mongolia, Arabic amber) whereas most of the changes we consider here took place far back in the Precambrian. Changes of enviromnental conditions may also contribute to stabilization of changes by substitution of some redox-inert ion with 3 func-... 

With the exception of burmite all the ambers mentioned so far are from the Tertiary period. There are many finds of amber from the Cretaceous period, 140 to 65 million years ago, but the vast majority of these are of little use as decorative material as they are far too brittle to work. They are usually found in very small pieces and tend to be a dull, opaque brown. They are, however, of great scientific interest, especially as some contain plant and animal inclusions. 

Among the Cretaceous ambers worth mentioning are those from ... 

Siberia has the world s largest Cretaceous amber deposit. It is thought to be about 100 million years old and lies in the permafrost, so is accessible for only a short period each year when the fixjzen ground thaws. 

Europe has its own Cretaceous amber. Deposits have been found in, among other places, England (the Isle of Wight), France, Denmark and Austria. They date from 130 to 100 million years old. 

The following does not apply to Cretaceous amber, with the exception... 

Fig. 19.24. Comparison of spectra of typical Eocene Baltic amber with those from Cretaceous amber from Maryland, Charleston, South Carolina, and Manitoba, Canada. (Langenheim and Beck, 1965.)...

Cooper, K.W. (1964). The first fossil tardigrade Beorn leggi Cooper, from Cretaceous amber. Psyche 71,41-48. 

Anderson, K.B., The nature and fate of natural resins in the geosphere. IV. Middle and upper Cretaceous amber from the Taimyr Peninsula, Siberia evidence for a new structural subclass of resinite, Org. Geochem., 21 209-212 (1994). 

Grimaldi, D., A. Shedrinsky, and T. Wampler, A remarkable deposit of fossiliferous amber from the Upper Cretaceous (Turonian) of New Jersey, in Studies on Fossils in Amber, with Particular Reference to Cretaceous of New Jersey, D. Grimaldi, Ed., Backhuys Publishers, Leiden (2000), pp. 1-76. 

Grimaldi, D., J. Ldlegraven, T. Wampler, D. Bookwalter, and A. Shedrinsky, Amber from Upper Cretaceous through Paleocene strata of the Hanna Basin, Wyoming, with evidence for source and taphonomy of fossil resins. Rocky Mountain Geoi, 35 163-204 (2000). 

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