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Index fossils must have a short vertical range, wide geographic distribution and rapid evolutionary trends. Another term, "zone fossil", is used when the fossil has all the characters stated above except wide geographical distribution; thus, they correlate the surrounding rock to a biozone rather than a specific time period.
Ausia fenestrata is a curious Ediacaran period (635 – 539 million years ago) [2] fossil represented by only one specimen 5 cm long from the Nama Group, a Vendian to Cambrian group of stratigraphic sequences deposited in the Nama foreland basin in central and southern Namibia. [1]
Graptolite fossils have predictable preservation, widespread distribution, and gradual change over a geologic time scale. This allows them to be used to date strata of rocks throughout the world. [8] They are important index fossils for dating Palaeozoic rocks as they
Oppel's zones are named after a particular distinctive fossil species, called an index fossil. Index fossils are one of the species from the assemblage of species that characterize the zone. Biostratigraphy uses zones for the most fundamental unit of measurement. The thickness and range of these zones can be a few meters, up to hundreds of meters.
Pages in category "Index fossils" The following 46 pages are in this category, out of 46 total. This list may not reflect recent changes. ...
Multiple exceptionally preserved specimens, among the best preserved bat fossils, are known from the Green River Formation of North America. [1] [2] The best known species is I. index. [3] Fragmentary material from France has also been tentatively placed within Icaronycteris as the second species I. menui. [4]
Inoceramus cuvieri are found throughout both middle Turonian Europe and the middle Turonian Western Interior Seaway. [3]In the High Plains of North America, I. cuvieri is an index fossil of the chalky lower Carlile Shale and upper Greenhorn Limestone and the corresponding bedding of the Mancos Shale, and shells of juveniles are particularly common in the Fencepost limestone bed.
Archaeopteris is an extinct genus of progymnosperm tree with fern-like leaves.A useful index fossil, this tree is found in strata dating from the Upper Devonian to Lower Carboniferous), the oldest fossils being 385 million years old, [1] and had global distribution.