کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4682565 1348925 2012 12 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Ñuagapua (Chaco, Bolivia): Evidence for the latest occurrence of megafauna in association with human remains in South America
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات علوم زمین و سیاره ای (عمومی)
پیش نمایش صفحه اول مقاله
Ñuagapua (Chaco, Bolivia): Evidence for the latest occurrence of megafauna in association with human remains in South America
چکیده انگلیسی

Quebrada (stream) Ñuagapua, which is located in the Bolivian Chaco in the Andean foothill generates an alluvial fan many kilometres in length. Three major lithostratigraphic units characterise the sedimentary sequence in this region. The lower and upper parts are formed from predominantly sandy sediments that demonstrate rapid growth of the alluvial fan, associated with an intense erosion of barren slopes. The intermediate unit consists of forest soil that seals deep channels containing bones together with a forest association. The remains of a wooden plank, dated 140 yr BP, were found at the top of this soil, which laterally contains charcoals, ash layers and large charred trunks, sometimes in growth positions. Roots localised in this layer also sustain a number of very large still living trees. These findings are evidence of a recent phase of alluvial fan sedimentation resulting from slope erosion activated by forest clearing. The Chaco has been intensively settled for agricultural and pastoral purposes since the 18th century. The lower unit contains a hearth, scattered burnt bones, flint flakes and ceramic artefacts. Radiometric dating indicates a middle Holocene human occupation, between ca. 7.79 and 6.65 ka cal yr BP. We suggest that the sedimentary unit is associated with intense soil erosion processes triggered by early Neolithic deforestation. A sandy layer of the lower unit, slightly above the archaeological remains, contains transported bones of megafaunal elements that apparently represent the South American latest occurrence of some extinct taxa. The mammal association is highly heterogeneous, containing species living in aquatic, forest, prairie and savannah environments from a very specific layer that represents the almost simultaneous burial of animals killed slightly up-valley. This anomalous association is probably the result of human impact as opening the forest favoured the introduction of open environment fauna that had previously survived on the southernmost part of the continent. Therefore, humans may have played a role in mammalian extinctions in this region, either directly, due to hunting, or due to changing the paleoenvironmental conditions on a wider scale.


► Ñuagapua alluvial fan (Bolivia) contains extinct megafauna, a hearth, flint artefacts and pottery dated 7.8–6.6 cal ka BP.
► It constitute the latest occurrence of Megafauna in South America.
► Sedimentation was due to soil erosion following deforestation in the early Holocene and in the last 200 yrs.
► Humans played a major role in mammalian extinction due to hunting but mostly changing the paleoenvironmental conditions.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of South American Earth Sciences - Volume 33, Issue 1, February 2012, Pages 56–67
نویسندگان
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