Chiapas amber
Chiapas amber is the name of a variety of amber found in the southern Mexican province of Chiapas , for which a Miocene age (approx. 13 to 20 million years) is assumed.
Find area
The amber , embedded in sand-lime stone sediments with layers of lignite , is mainly found in the area of the municipality of Simojovel . The term "Mexican amber", which is often used for amber from Chiapas, is misleading in that amber is also found in other areas of Mexico, such as the Cretaceous amber in Baja California in the north of the country, which is known as bacalite in the Anglo-Saxon-speaking area .
Chemical and physical characteristics
The amber ranges in color from transparent yellow to dark red. The dark red specimens are mostly found near the surface; this suggests that the color is due to oxidation . In the Anderson & Crelling classification system for fossil resins , Mexican amber is assigned to class 1c. The structure of the resins in this category is characterized by polymers and copolymers of labdanoid diterpenes and they lack succinic acid . The Chiapas amber has an unusually high carbon content with a correspondingly low oxygen content.
Botanical origin and palaeo-habitat
An extinct representative of the genus Hymenaea is considered to be the mother plant of the resin from which Chiapas amber originated . Poinar & Brown (2002) called the species Hymenaea mexicana . Presumably it is a close relative of the species Hymenaea courbaril (known in Mexico under the name "Guapinol"), which is still growing in Mexico today . The Miocene "Mexican amber forest" is based on the amber inclusions as part of a mangrove forest or at least as a forest area in its immediate vicinity.
History and economic importance
Chiapas amber was already known to the inhabitants of the find area in pre-Columbian times. The amber was used by the Indians for jewelry and ritual objects and was probably also used as a means of payment. The first Spanish conquistadors are said to have learned of the existence of the amber deposit. Even today amber is extracted by the rural population from tunnels and shafts they dug themselves. The total yield is estimated at 100 to 200 kilograms per year and some of it is processed into jewelry in local craft shops.
Scientific collections and fossils
The amber was first mentioned scientifically at the turn of the 19th and 20th centuries; from the 1950s onwards, Chiapas amber was systematically processed scientifically.
Important scientific collections of Mexican amber can be found in the State Museum of Natural History Stuttgart, the University of California, Museum of Paleontology, Berkeley, USA and in the Museum of Paleontology in Tuxla Gutiérrez Chiapas, Mexico. The pieces in these collections contain several thousand organic inclusions, including representatives from more than 175 arthropod families. The composition of the fossil society is similar to that of the Dominican amber of the same age .
See also
literature
The information in this article is essentially based on the following literature sources:
- PD Hurd, RF Smith; JW Durham: The fossiliferous amber of Chiapas, Mexico. - In: Ciencia 21 (1961): 107-118, Mexico City 1962.
- Jean H. Langenheim & Curt W. Beck: Catalog of Infrared Spectra of Fossil Resins (Amber) I - North and South America. - In: Botanical Museum Leaflets , Harvard University, Vol. 22, No. 3: 65-120, Cambridge (MA) 1968.
- G. Poinar, A. Brown, A .: Hymenaea mexicana sp. nov. (Leguminosae: Caesalpinioideae) from Mexican amber indicates Old World connections . In: Botanical Journal of the Linnean Society 139 (2): 125-132, London 2002.
- George O. Poinar Jr .: Life in Amber , Stanford (USA) 1992.
- Dieter Schlee: Amber - amber and amber fossils. - In: Stuttgart Contributions to Natural History , Series C, Issue 8, Stuttgart 1978.
- Mónica M. Solórzano Kraemer: Mexican Amber. - In: David Penney (Ed.): Biodiversity of the fossils in amber from the major world deposits : 42–56, Manchester (UK) 2010.
Web links
- Museo del Ambar in San Cristóbal de Las Casas, Chiapas, México (Spanish and English)
- Website of David Gibson on Mexican amber with pictures from the excavation site and further information on the role of amber in pre-Columbian times (English)