New Mexico Geological Society Annual Spring Meeting — Abstracts

Fossil resins (amber) are a complex mixture of extensively polymerized organic molecules of worldwide distribution and is found in soil, coal, rock or petroleum. Although doubtful examples of fossil resin have been reported from the Late Paleozoic, most amber occurs in Late cretaceous to Tertiary strata. Although fossil resins have long intrigued man, little is actually known about their botanical origin, chemistry or diagenetic history. The term "amber" is applied to fossil resins of different origins and properties. We recognize four genetic types of fossil resin: 1) Primary ambers include those fossilized in situ and after deposition is neither transported nor metamorphosed. 2) Secondary ambers are those squeezed out of coal and lignite during coalification. 3) Tertiary ambers are primary or secondary resins that have been transported, buried and metamorphosed to varying degrees. 4) Quaternary resins are those found in petroleum. Various types of inclusions are found in fossil resins; the fluid inclusions are of the following types: 1) atmospheric; 2) degradation products of the resin matrix; 3) hydrous; 4) gases given off by the decomposition of entrapped biota; 5) coal gases produced by coalification; 6) liquid hydrocarbons; 7) gases from maturation of sediments; 8) inorganic inclusions such as CaSO₄. In all cases the composition of the inclusion is modified by reactions with degradative products of the resin matrix, the matrix itself and diffusion. Fluid inclusion studies must consider the chemical nature of fossil resins and any diagenetic influences. Studies of fossil resins must consider the fact that genetic types of amber describe end members on a multidimensional spectrum.