“Cueva Fell”的意思、由来-开放百科全书

Fell's Cave was discovered by Junius Bird. It came to his attention because arrow points and flakes were found on the surface. The cave was originally called the Río Chico shelter, but was later renamed by Bird to Fell's Cave in honor of the Fell family who owned the Estancia Brazo Norte, the North Arm Station, where the cave is located.^[3] Excavation of the site began in 1936.

Site formation

Fell's Cave is located in the Río Chico canyon, Chile, near the Straits of Magellan and the Argentine border. This area is known as the Southern Patagonian Basalt Plateaus.^[3] Situated on the southeast side of what was once a river bank, it is more accurately described as a rock shelter. It was formed by river water wearing away at the sandstone bank, leaving behind a canopy of lava conglomerate and thus creating a shelter {{convert|28|ft|m|abbr=on}} deep and {{convert|38|ft|m|abbr=on}} wide. The erosion formed a smooth floor of hard clay.^[4] Remnants of sandstone still clinging to the conglomerate roof eventually fell to the floor, forming an archaeologically sterile layer that separated later human occupation periods.^[4]

Stratigraphy

Junius Bird labelled the occupational sediment layers of the site from top to bottom, the top layer directly under the surface is I and the oldest, lowest layer is V.

The surface material of the site is composed of dirt, rocks, and hard-packed sheep manure. The surface layer ranges from {{convert|18|to|24|in|cm|abbr=on}} in thickness.^[5]

The youngest stratigraphic layer of Fell's Cave is a dark earth layer, reaching approximately {{convert|10|in|cm|abbr=on}} in thickness.^[6] This component dates from around 700 years BP to the present.^[7] According to conventional radiocarbon dating, the layer dates to 1265 CE +-90.^[8]

The division between Layer I and Layer II is relatively indistinguishable as the sediments are of similar dark earth, and also reach about {{convert|10|in|cm|abbr=on}} or more in thickness.^[6] This layer dates to around 6,500 years BP.^[7]

This layer dates to around 8,500 to 6,500 years BP.^[7] The earth consistency between Layers II and III marking a notable distinction between the two. Layer III is approximately {{convert|12|to|15|in|cm|abbr=on}} thick and consists of compacted dark earth.^[6]

The thickness of this layer varies from {{convert|13|to|17|in|cm|abbr=on}} and consists of firmly packed dark earth.^[15] This layer dates from c. 10,000 to 8,500 years BP.^[7]

After the earliest layer, Layer V, had accumulated, sandstone slabs fell from the roof of the cave and sealed it off. This layer is {{convert|15|to|20|in|cm|abbr=on}} thick.^[4]

A refuse soft clay soil varying in thickness from {{convert|3|to|9|in|cm|abbr=on}} composes the oldest occupation level at the site.^[9] The site dates from 11,000 +-170 years BP to 10,080 +-160 years BP according to conventional radiocarbon dating.^[8]

Chronology

Bird named the periods from earliest to latest, thus Period I is the oldest and is associated with Layer V, while Period V is the latest and is associated with Layer I.

This period (layer I) is typified by a tool assemblage containing small arrow points and various bone tools, as well as such cultural materials as combs and beads.^[7] Based on the style of the arrow points, it is likely that this period is associated with the Ona Indians.^[7] The faunal assemblage of this period is dominated by guanaco bone fragments.^[6]

Period IV is characterized by the presence of stone tools such as stemmed or legged stone points, knives, and small thumb-nail scrapers as well as a bone tool assemblage.^[23] Large bolas, various beads and other ornaments are also present.^[10] This Period can also be distinguished by the building of structures including extended burials and rock cairns.^[10] Again, the faunal assemblage is dominated by guanaco.^[15]

Present in this layer are bone awls, stone scrapers, and triangular stone points with rounded bases. Also, bolas of notably smaller size than the subsequent later period, period IV.^[7] It has been suggested that these small stone bolas may have been used in procurement of birds.^[7] Guanaco and fox bone fragments dominate the faunal assemblage.^[6]

This layers consists mainly of bone points and awls, and stone scrapers.^[7] Junius Bird notes in Travels and Archaeology in South Chile that this layer contained significantly more sediment in relation to artifact distribution.^[11]

The oldest cultural occupation at this site belongs to the Fell's Tradition.^[12] Thus, Fell's Cave is the type site for the Fell's Tradition. This tradition is characterized most notably by fishtail points as well as various stone scrapers, choppers, stone discs and bone tools.^[7] Several hearths were also excavated from this level which produced three radiocarbon dates between c.11,000 and 10,000 years BP.^[7]

Ecology

Climate

In the Late Pleistocene, prior to 12,500 years BP, the area surrounding Cueva Fell was dominated by high winds, year-round freezing temperatures, and annual precipitation under 300 mm. This heathland environment was replaced by a treeless, xeric, herbaceous steppe environment through 11,000 years BP, as the freezing temperatures and winds began to abate.^[13]^[14] This is the climate and terrain that most closely predated the first human inhabitants in the area.

The earliest human occupation dates suggested by the finds in Layer V—c. 11,000 to 10,000 years BP correspond to a period of stadial cooling. In what has been described as a possible South American equivalent to the Younger Dryas, the Patagonian region experienced a period of low temperatures and high precipitation as well as advancing glaciers.^[15] This was followed in 10,000 to 9,000 years BP by a warming trend. These two thousand years in question marked a fitful end to the last ice age, one marked by high environmental variability. While this produced significant changes in some taxa, humans, at this time, were already becoming adept at adjusting to new environments and appear not to have been deleteriously affected by the changeable and unpredictable climate.^[16]

As the Holocene warming trend persisted, so the environment of southern Patagonia continued to change. The archaeology of Fell's Cave provides evidence for the regular occurrence of summer droughts in the area—droughts that, combined with increasing summer storm activity, may have led to wildfires. The decrease in water availability combined with the evident (through pollen analysis) dramatic change in grazing flora species, are proposed as contributing factors to the evident faunal extinction.^[17]^[18]

The period of 9,000 to 6,000 years BP saw less remarkable shifts in climate, with a general trend away from xeric taxa and, it is then presumed, an increase in precipitation. There is insufficient radiocarbon control at the site to determine local climate conditions post-6,000 years BP, however regional ecology suggests a slight shift towards more aridity.^[19]

Today Cueva Fell joins most of southern Argentina in what is known as the Fuego-Patagonia steppe environment. The area receives less than {{convert|400|mm|in|abbr=on}} annual precipitation (typical for the Patagonia region but much drier than neighbouring coastal or mountain terrains) and is dominated by bunch grasses from the genera Festuca and Stipa, along with a variety of herbaceous vegetation.^[20]

Flora & fauna

Cueva Fell is notable for the range of now-extinct faunal finds excavated from within it. Notable among these are the giant sloth and the horse. The horse was to become extinct and absent in the Americas through most of the Holocene until it was imported by Europeans.^[21] In fact the evidence of the ancient horse Cueva Fell was the first proof that horses occupied the Americas before being reintroduced from the Old World. The stratified remains of both human and animals provides evidence that human occupation of the area actually preceded the extinction of both the native horse (Parahipparium saldasi) and the ground sloth. This same evidence suggested that ancient horse was hunted and eaten.^[22] However humans weren't the sole predators in the area. Bone remains of the horse, llama and ground sloth all display puncture marks, most likely made by the Patagonia panther.^[23]

The Early Holocene taxa change—the extinction of mostly herbivorous animals in South America—was initially attributed to human over-hunting, as were the megafaunal extinctions in North America. Analysis of pollen extracted from Cueva Fell suggested a substantial reduction in grassland in southern Patagonia in the period just preceding these extinctions, and was an early piece of evidence in the mounting argument against hunting as the primary cause of species collapse.^[3] Large quantities of guanaco (lama) were also found in the older depositional layers. Where other large grazing fauna died out in the early Holocene, guanaco appear to have survived as a result of their less specialized plant diet, adapting to the change in vegetation that accompanied the warming Holocene. Guanaco population sizes initially dipped along with other grazing species, but eventually recovered.^[24]

Analysis of canine remains found in all five human occupation levels of the cave initially suggested they were those of domestic dog (Canis familiaris). This would have been remarkable as the earliest evidence for the domestic dog in the Americas. However subsequent analyses suggest the skull and teeth remains to have been from two wild species: Pseudalopex griseus (South American gray fox) and Canis avus (a small fox or wolf-life canine, particular to South America in the late Pleistocene period).^[25] Other faunal bone remains include hawks and falcons.^[23]

Artifacts

The first excavation of Fell's cave in 1936 yielded 511 artefacts. These included hafted implements, knives, scrapers, bolas, a couple of circular rubbing stones, and bone tools.^[50]

Perhaps the most significant find in the 1936 excavation was the fishtail projectile point. All of the fishtail points were associated with large mammals including: extinct horses, giant ground sloths, and guanacos. Fifteen fishtail projectile points were recovered from Layer V which is the oldest layer that dates back to 11,000 +-170 and 10,080 +-160 years BP. These fishtail point have been radiocarbon dated to be ca. 11,000 years old.^[27]

Discoidal stones, referred in the chart as circular rubbing stones, were also found. Bird notes in a 1970 journal article that “stone artefacts shaped by pecking and grinding are so generally absent among Paleo-Indian finds that exceptions are noteworthy”.^[28] There were two stones found in Cueva Fell; both of them were clearly associated with animal remains. Both were made from lava. The larger stone has a diameter of about {{convert|12.3|cm|in|abbr=on}} and weighs about {{convert|1.12|kg|lb|abbr=on}} while the smaller stone is about {{convert|8.4|cm|in|abbr=on}} in diameter and weighs about {{convert|0.5|kg|lb|abbr=on}}.^[29] There was also a substantial amount of scrapers found throughout all the Cueva Fell layers. The bone tools found, according to Bird, were made from sloth bone because there bone used showed no evidence of marrow cavities.^[30]

In 1969 there was a second dig organized at Cueva Fell but it was focused in a slightly different location of the cave. During this excavation 415 artifacts were found; various points, knives, scrapers, cores, bolas, and bone tools.

Site significance

The colonization of the New World

The colonization of the Americas may be one of the most contentious archaeological debates today. The issue involves a large body of research and numerous theories as to how and when this event began. For decades, the Clovis-first model^[32]^[33] trumped all other theories for the Settlement of the Americas. This theory basically holds that the Clovis culture constituted the earliest peoples to arrive in and inhabit North America. Entering the Americas from Asia via the Bering Land Bridge and migrating south through the ice free corridor, the Clovis people populated southern North America. This population spread through Central America and finally South America.

At the time the theory was proposed no archaeological evidence had been discovered in the Americas which pre-dated 11,050 to 10,800 years BP, or the onset of the Clovis culture. However, in the last few decades a multitude of sites were found, which at first challenged this theory and now demand a new model to explain the peopling of the Americas.^[34] Based on the current understanding of archaeological evidence, it is now widely accepted that a pre-Clovis culture colonized the Americas via a Pacific coastal route sometime between 14,000 and 12,000 years BP.^[35]

Some of the evidence supporting the coastal theory comes from the southern-most portions of South America. Many researchers now agree that occupation of Tierra del Fuego, between 11,000 and 10,500 years ago, simply does not provide enough time for mid-continental migration. A similar argument is made about Monte Verde, which may be the best known and most widely accepted of these sites and which pre-dates Clovis by approximately 1,000 years.

Although site discovery and excavation were not recent, Cueva Fell is representative of occupation of southern South America. The earliest occupation at Cueva Fell, between 11,000 +-170 and 10,080 +-160 years BP, does not pre-date but is coeval with Clovis.^[36] Other Late Pleistocene sites in Argentina, such as Cerro Tres Tetas, Cueva Casa del Minero and Piedra Museo are also contemporaneous with Clovis and the early occupation at Fell's Cave.^[34]

Stone tool technology

The common tendency to compare South American and North American prehistory is increasingly becoming outmoded, most notably in regards to early technological adaptations. It has been long believed that the early fluted points of South America represented a diffusion of the fluted North American Clovis points. South American fluted points include the fishtail point represented at Cueva Fell and many other regions, the El Jobo point (Venezuela), and the Paijan point (Peru and Ecuador), all of which dating to Clovis times.^[37]

The fluted stone tool variants of South America represent regional adaptations to the procurement of Pleistocene megafauna that contrasts with the continent-wide use of Clovis points in North America.^[38] Such regional technological adaptations seem to reflect the initial dispersal of small paleoindian groups throughout the vast continent. The fishtail points of Cueva Fell thus represent crucial evidence in the distinction between tool technologies in the southern and northern continents of the Americas.

Site discovery in Fuego-Patagonia

Finally, Cueva Fell deserves recognition for representing possibly the earliest occupation of Fuego-Patagonia approximately 11,000 BP.^[39] This southern region of South America is symbolic of "the end of the line" for the initial colonization of the New World.

The early inhabitants of Fuego-Patagonia signify sparse populations spread out over large territories and chances of site discovery in this region are low.^[66] Compounding the low likelihood of site discovery in this region is the deeply buried contexts associated with such early occupation and the subsequent increase of various perturbation processes threatening the archaeological integrity.^[40] Many of these sites, Cueva Fell included, are rock shelters which have been used as dens by carnivorous fauna over thousands of years, which not only disturb archaeological deposits but add difficulty to recognizing archaeological sites.^[40] Low population density combined with these other factors make Junius Bird's discovery of Cueva Fell in 1936 truly remarkable in and of itself.

Site discovery