archaeology Archaeology or archeology is the study of human activity through the recovery and analysis of material culture. The archaeological record consists of Artifact (archaeology), artifacts, architecture, biofact (archaeology), biofacts or ecofacts, ...

and

paleontology Paleontology, also spelled as palaeontology or palæontology, is the scientific study of the life of the past, mainly but not exclusively through the study of fossils. Paleontologists use fossils as a means to classify organisms, measure ge ...

a faunal assemblage is a group of animal

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...

s found together in a given

stratum In geology and related fields, a stratum (: strata) is a layer of rock or sediment characterized by certain lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by visible surfaces known as ...

. In a non-deformed deposition, fossils are organized by stratum following the laws of

uniformitarianism Uniformitarianism, also known as the Doctrine of Uniformity or the Uniformitarian Principle, is the assumption that the same natural laws and processes that operate in our present-day scientific observations have always operated in the universe in ...

and

superposition In mathematics, a linear combination or superposition is an expression constructed from a set of terms by multiplying each term by a constant and adding the results (e.g. a linear combination of ''x'' and ''y'' would be any expression of the form ...

, which state that the natural phenomena observable today (such as death, decay, or post-mortem transport) also apply to the paleontological record and that the oldest stratum will be at the bottom of a paleontological deposit. The

principle of faunal succession The principle of faunal succession, also known as the law of faunal succession, is based on the observation that sedimentary rock strata contain fossilized flora and fauna, and that these fossils succeed each other vertically in a specific, reli ...

is used in

biostratigraphy Biostratigraphy is the branch of stratigraphy which focuses on correlating and assigning relative ages of rock strata by using the fossil assemblages contained within them.Hine, Robert. "Biostratigraphy." ''Oxford Reference: Dictionary of Biology ...

to determine each biostratigraphic unit, or

biozone In biostratigraphy, biostratigraphic units or biozones are intervals of geological strata that are defined on the basis of their characteristic fossil taxon, taxa, as opposed to a Lithostratigraphy, lithostratigraphic unit which is defined by the ...

. The biostratigraphic unit is a

section Section, Sectioning, or Sectioned may refer to: Arts, entertainment and media * Section (music), a complete, but not independent, musical idea * Section (typography), a subdivision, especially of a chapter, in books and documents ** Section sig ...

of geological strata that is defined on the basis of its characteristic fossil

taxa In biology, a taxon (back-formation from ''taxonomy''; : taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and ...

or faunal assemblage. Faunal assemblages are also analyzed in archaeological deposits, where they are influenced by cultural activities in addition to ecological processes and natural taphonomy.

Taphonomy

Taphonomy Taphonomy is the study of how organisms decay and become fossilized or preserved in the paleontological record. The term ''taphonomy'' (from Greek language, Greek , 'burial' and , 'law') was introduced to paleontology in 1940 by Soviet scientis ...

is translated from Greek as "laws of burial" (''taphos + nomos''). From death to discovery, many processes can affect the burial and preservation of a faunal assemblage including decay, transport,

bioturbation Bioturbation is defined as the reworking of soils and sediments by animals or plants. It includes burrowing, ingestion, and defecation of sediment grains. Bioturbating activities have a profound effect on the environment and are thought to be a ...

biostratinomy Biostratinomy is the study of the processes that take place after an organism dies but before its final burial. It is considered to be a subsection of the science of taphonomy, along with necrology (the study of the death of an organism) and diag ...

(physical alterations due to sedimentation), and

diagenesis Diagenesis () is the process of physical and chemical changes in sediments first caused by water-rock interactions, microbial activity, and compaction after their deposition. Increased pressure and temperature only start to play a role as sedi ...

(the process by which organic material is converted to mineral). Based on these preservation factors, skeletons and hard parts are most likely to be preserved in faunal assemblages. Taphonomic processes can cause significant "information loss". Most often if an animal dies, the flesh decays first, leaving its bones susceptible to taphonomic processes. Preservation depends on mineral composition and preservation varies with bone density as well as sediment composition. For example, arid or highly saline conditions preserve bones better than wet acidic environments. Other environments that are more likely to preserve faunal remains include sediment slumps in lakes, sink holes, or caves. In these cases, faunal assemblages may represent long-term accumulation rather than one-time events.

Life vs. Death Assemblages

Life and death assemblages are differentially defined in

and

Paleontology

A life assemblage is a faunal assemblage consisting of a single biological community preserved in the environment in which it lived. Conversely, a death assemblage is composed of species that did not live in the place they were deposited and incorporated into the paleontological record. A mixed assemblage contains both non-transported and transported fossils. PSM_V84_D343_Richness_of_deposit_of_the_fossils_in_rancho_la_brea_diggings

PSM_V84_D343_Richness_of_deposit_of_the_fossils_in_rancho_la_brea_diggings

Time-averaging is the phenomenon in which geologic events appear to have happened at the same time based on pooling available fossil evidence. Time-averaging occurs when faunal assemblages are mixed across chronological strata and varies across faunal assemblages. For life assemblages in which a community was completely buried ''in-situ'' by a sudden event such as a storm or mudslide, time averaging does not affect interpretation. However, most faunal assemblages are mixed or death assemblages which have been affected by taphonomic processes which influence paleontological analysis and interpretation. Although

radiocarbon dating Radiocarbon dating (also referred to as carbon dating or carbon-14 dating) is a method for Chronological dating, determining the age of an object containing organic material by using the properties of carbon-14, radiocarbon, a radioactive Isotop ...

is expensive and not possible for specimens older than 50,000 years, when individual bones can be dated researchers can avoid the problems associated with time-averaging. A frequently used faunal assemblage in paleontology and paleoclimatology is the use of foraminifera assemblages as a proxy of past climate and sea levels. Foraminifera are marine microorganisms that are abundant in most parts of the world's ocean and are indicators of ocean temperature, salinity, upwelling intensity, primary productivity, and more. Hominid evolution can also be tracked alongside shifting faunal assemblages. For example, in

East Africa East Africa, also known as Eastern Africa or the East of Africa, is a region at the eastern edge of the Africa, African continent, distinguished by its unique geographical, historical, and cultural landscape. Defined in varying scopes, the regi ...

, a distinctive group of animal species, mostly suids and elephantoids, is characteristic of the fossils preserved from 3.5 Ma to 4.5 Ma. This faunal assemblage has been used effectively to chronologically correlate the East African early hominid sites. Faunal assemblages are useful in determining the foraging patterns of hominids. One such assemblage at Lang Rongrien in Thailand indicated a hunter-gatherer group which was highly flexible when it came to finding food. They relied heavily on turtle and tortoise to supply the meat portion of their diet when hunting large game was unpredictable. This assemblage also suggested the paleoenvironment was drier and cooler than today because of a distinct lack of pig bones.

Archaeology

In archaeology a life assemblage is defined as the animal community which co-occurred in time and space with the human population that created the archaeological deposit. A death assemblage, on the other hand, is that which is used by people and preserved in an archaeological site. If using the paleontological definition of a death assemblage, in archaeology, the faunal assemblage is inherently a death assemblage, since archaeologists assume that humans killed the animals found within the deposits. The taphonomic modifications made by cultural processes are split into two categories, the first being those which the archaeologist cannot control and the second being a direct consequence of an archaeologists' methods. Archaeological deposits are always affected by cultural processes and therefore represent human activities, rather than a complete ecological community. These human activities may include subsistence hunting, agriculture, ritual use, and more. An example of a taphonomic disadvantage in archaeological faunal assemblages is the effects of domestic dogs on the assemblages. By scavenging or through direct feeding by their human counterparts, dogs and other canids can such severe damage to the bones that identification by archaeologists is impossible. This causes site interpretation problems.

References

* Dawson, Peter Colin (1993) ''From death assemblage to fossil assemblage understanding the nature of intra-site and inter-site variability in faunal assemblages'' National Library of Canada, Ottawa, * * Crabtree, Pam J. (2005) ''Exploring Prehistory: How archaeology reveals our past'' McGraw-Hill, Boston p. 450,

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