Variation in the deterioration of fossil resins and implications for the conservation of fossils in amber

Title Variants

Alternative: Deterioration of amber

Related Titles

Series: American Museum novitates, no. 3734

By

Bisulca, Christina.
Nascimbene, Paul C.
Elkin, Lisa, 1966-
Grimaldi, David A.

Type

Book

Material

Published material

Publication info

[New York], American Museum of Natural History, c2012

Notes

Caption title.

"February 23, 2012."

"The Division of Invertebrate Zoology at the American Museum of Natural History houses a ... collection of fossiliferous amber, including material ranging from the early Cretaceous (145-110 Ma) to as recent as the Holocene"--P. 2.

The deterioration of fossil resins (crazing, cracking, and darkening) was investigated by comparing the effects of one year of accelerated aging--specifically intensive exposure to light, heat, and fluctuating humidity, both individually and in combination--on samples from several natural resin deposits. These included two Cretaceous ambers (from Myanmar (Burma) and central New Jersey), two Tertiary ambers (from the Baltic and the Dominican Republic), and Holocene copal from Zanzibar. The five resins were chosen for their disparate ages and botanical origins (and thus chemical and physical properties), as well as their paleontological significance. In all cases, pronounced deterioration occurred under combined exposure to light and fluctuating humidity, based on surface crazing and a decrease in absorbance of light in the UV region (360-400 nm). While crazing did not visibly occur in cases of fluctuating humidity in dark conditions, or UV exposure alone, spectrophotometric evidence indicates that some deterioration did take place. Yellowing after exposure to elevated temperatures occurred in all samples tested, with the exception of Burmese amber. All four true ambers exhibited a decrease in UV absorbance after exposure to heat (while copal actually showed an increase). The samples from the five deposits represent three chemical subclasses of fossil resins, and each of the resins reacted differently to the various aging conditions, with New Jersey amber particularly unstable. Based on these results, amber collections should be stored in an environment with stable humidity, relatively low heat, and minimal exposure to light. Anoxic sealing and storage, and particularly embedding amber samples in a high-grade epoxy, may be beneficial, and further investigation is indicated.

Subjects

Amber , Amber fossils , American Museum of Natural History , Catalogs and collections , Collection and preservation , copal , Deterioration , Division of Invertebrate Zoology , Museum conservation methods , New York , New York (State) , Resins, Fossil

Call Number

QL1 .A436 no.3734 2012

Language

English

Identifiers

OCLC: 777955134