Wiki: Dominican amber - upcScavenger

Dominican amber is amber from the Dominican Republic derived from resin of the extinct tree Hymenaea protera.

Dominican amber differentiates itself from Baltic amber by being nearly always transparent, and it has a higher number of fossil inclusions. This has enabled the detailed reconstruction of the ecosystem of a long-vanished tropical forest.George Poinar, Jr. and Roberta Poinar, 1999. The Amber Forest: A Reconstruction of a Vanished World, (Princeton University Press)

Age

The age of the amber has been controversial. A study in the early 1990s returned a date up to 40 million years old. However, other authors have suggested a date in the Miocene, around 20–15 million years old, based on marine microfossils found in the sediment the amber is contained in.

Mining sites

There are three main sites in the Dominican Republic where amber is found: La Cordillera Septentrional, in the north, and Bayaguana and Sabana de la Mar, in the east. In the northern area, the amber-bearing unit is formed of clastic rocks, washed down with sandstone fragments and other sediments that accumulated in a River delta environment, even in water of some depth.Leif Brost and Ake Dahlstrom. The Amber Book, Geoscience Press, Inc., Tucson , AZ, 1996 Wilfred Wichard und Wolfgang Weitschat: Im Bernsteinwald. - Gerstenberg Verlag, Hildesheim, 2004, Baroni Urbani, C. & Saunders, J.B. (1980): The fauna of the Dominican Republic amber: the present status of knowledge. – Memorias, 9a geologica del Caribe, 1: 213–223; Santo Domingo. (Published 1983).

In the eastern area, the amber is found in a sediment formation of organic-rich laminated sand, sandy clay, intercalated lignite, and as well as some Solvation beds of gravel and calcarenite.Schlee, D. (1984): Besonderheiten des Dominikanischen Bernsteins. – Stuttgarter Beitr. Naturk., C, 18: 63-71; Stuttgart.

Both areas seem to have been part of the same sedimentary basin but were later disrupted by movements along major faults.Manuel A. Iturralde-Vennet 2001. Geology of the Amber-Bearing Deposits of the Greater Antilles. Caribbean Journal of Science, Vol. 00, No. 0, 141–167, 2001

Mining

Dominican amber, especially Dominican blue amber, is mined through bell pitting, which is extremely dangerous. The bell pit is basically a foxhole dug with whatever tools are available. Machetes do the start, some shovels, picks and hammers may participate eventually. The pit itself goes as deep or safe as possible, sometimes vertical, sometimes horizontal, but never level. It snakes into hill sides, drops away, joins up with others, goes straight up and pops out elsewhere. 'Foxhole' applies indeed: rarely are the pits large enough to stand in, and then only at the entrance. Miners crawl around on their knees using short-handled picks, shovels and machetes.

There are few to no safety measures. A pillar or so may hold back the ceiling from time to time but only if the area has previously collapsed. Candles are the only source of light. Humidity inside the mines is at 100%. Since the holes are situated high on mountainsides and deep inside said mountains, the temperature is cool and bearable, but after several hours the air becomes stale. During rain the mines are forced to close. The holes fill up quickly with water, and there is little point in pumping it out again (although sometimes this is done) because the unsecured walls may crumble.Martínez, R. & Schlee, D. (1984): Die Dominikanischen Bernsteinminen der Nordkordillera, speziell auch aus der Sicht der Werkstaetten. – Stuttgarter Beitr. Naturk., C, 18: 79-84; Stuttgart.

Variations

Dominican amber can be found in many colors, besides the obvious amber. Yellow and honey colored are fairly common. There is also red and green in smaller quantities and the rare blue amber (fluorescent).Schlee, D. (1980): Bernstein-Raritaeten (Farben, Strukturen, Fossilen, Handwerk). – 88 S. (mit 55 Farbtafeln); Staatl. Museum für Naturkunde Stuttgart.

The blue amber reportedly is found mostly in Palo Quemado mine south from La Cumbre.

The Museo del Ambar Dominicano, in Puerto Plata, as well as the Amber World Museum in Santo Domingo have collections of amber specimens.

Paleobiology

Numerous organisms have been described from amber specimens including:

Protozoans