The skeletal remains of a Paleoamerican (Naia; HN5/48) and extinct megafauna were found at −40 to −43 mbsl in a submerged dissolution chamber named Hoyo Negro (HN) in the Sac Actun Cave System, ...Yucatan Peninsula, Mexico. The human remains were dated to between 12 and 13 Ka, making these remains the oldest securely dated in the Yucatan. Twelve sediment cores were used to reconstruct the Holocene flooding history of the now phreatic cave passages and cenotes (Ich Balam, Oasis) that connect to HN. Four facies were found: 1. bat guano and Seed (SF), 2. lime Mud (MF), 3. Calcite Rafts (CRF) and 4. Organic Matter/Calcite Rafts (OM/CRF) which were defined by their lithologic characteristics and ostracod, foraminifera and testate amoebae content. Basal radiocarbon ages (AMS) of aquatic sediments (SF) combined with cave bottom and ceiling height profiles determined the history of flooding in HN and when access was restricted for human and animal entry. Our results show that the bottom of HN was flooded at least by 9850 cal yr BP but likely earlier. We also found, that the pit became inaccessible for human and animal entry at ≈8100 cal yr BP, when water reaching the cave ceiling effectively prevented entry. Water level continued to rise between ≈6000 and 8100 cal yr BP, filling the cave passages and entry points to HN (Cenotes Ich Balam and Oasis). Analysis of cave facies revealed that both Holocene sea-level rise and cave ceiling height determined the configuration of airways and the deposition of floating and bat derived OM (guano and seeds). Calcite rafts, which form on the water surface, are also dependent on the presence of airways but can also form in isolated air domes in the cave ceiling that affect their loci of deposition on the cave bottom. These results indicated that aquatic cave sedimentation is transient in time and space, necessitating extraction of multiple cores to determine a limit after which flooding occurred.
•We reconstruct the water table response to Holocene sea-level rise.•Model the flooding history of Sac Actun Cave in Quintana Roo, Mexico.•Utilize microfossils and sedimentary sequences to study sedimentation in Hoyo Negro.•Contribute to understanding site formation of a significant archaeological site.•Provide a minimum age for mammalian skeletons in Hoyo Negro.
The Cradle of Humankind cave sites in South Africa preserve fossil evidence of four early hominin taxa:
Australopithecus africanus,
Australopithecus sediba,
Paranthropus robustus and early
Homo. In ...order to integrate this record into a pan-African scenario of human evolutionary history it is critical to have reliable dates and temporal ranges for the southern African hominins. In the past a lack of precise and accurate chronological data has prevented the evaluation of the temporal relationships between the various sites. Here we report new uranium–lead (U–Pb) radiometric ages obtained from sheets of calcium carbonate flowstone inter-bedded between clastic cave sediments at the site of Swartkrans, providing bracketing ages for the fossiliferous deposits. The fossil bearing units of Swartkrans, specifically the Hanging Remnant and Lower Bank of Member 1, are underlain by flowstone layers dated to 2.25
±
0.05
Ma and 2.25
±
0.08
Ma and capped by layers of 1.8
±
0.01
Ma and 1.7
±
0.07
Ma. The age bracket of the Member 1 deposits is therefore between 2.31 and 1.64
Ma. However, by combining the U–Pb with biostratigraphic data we suggest that this can be narrowed down to between 1.9 and 1.8
Ma. These data can be compared with other recently dated sites and a radiometrically dated U–Pb age sequence formed: Sterkfontein Member 4, Swartkrans Member 1, Malapa, and Cooper's D. From this new U–Pb dataset, a pattern of contemporary flowstone development emerges, with different caves recording the same flowstone-forming event. Specifically overlapping flowstone formation takes place at Swartkrans and Sterkfontein at ~
2.29
Ma and ~
1.77
Ma, and at Sterkfontein and Malapa at ∼
2.02
Ma. This suggests a regional control over the nature and timing of speleothem development in cave deposits and these flowstone layers could assist in future correlation, both internal to specific deposits and regionally between sites.
► South African cave sites preserve early human (hominin) fossils; ► Previously sites and fossils were not directly or thoroughly dated; ► We use Uranium-Lead dating on flowstones to provide precise new ages; ► Three time periods record contemporary flowstone growth, aiding in correlation; ► Now possible to integrate South African fossils into scenarios of human evolution
Quaternary climate and sea-level research in coastal karst basins (caves, cenotes, sinkholes, blueholes, etc.) generally focuses on analyzing isotopes in speleothems, or associating cave elevations ...prior sea-level highstands. The sediments in coastal karst basins represent an overlooked source of climate and sea-level information in the coastal zone, but to accurately interpret these sediments first requires an understanding of the forcing mechanisms that emplace them. In this study, we hypothesize that coastal karst basins transition through vadose, littoral, anchialine, and finally into submarine environments during sea-level rise because groundwater and sea level oscillate in near synchrony in the coastal zone, causing each environment to deposit a unique sedimentary facies. To test this hypothesis, the stratigraphy in twelve sediment cores from a Bermudian underwater cave (Green Bay Cave) was investigated and temporally constrained with twenty radiocarbon dates. The results indicate that we recovered the first succession spanning the entire Holocene from an underwater cave (~
13
ka to present). The sediments were characterized with X-radiography, fossil remains, bulk organic matter, organic geochemistry (δ
13C
org, C:N), and grain size analysis. Four distinct facies represent the four depositional environments: (i) vadose facies (>
7.7
ka, calcite rafts lithofacies), (ii) littoral facies (7.7 to 7.3
ka: calcite rafts and mud lithofacies), (iii) anchialine facies (7.3 to 1.6
ka: slackwater and diamict lithofacies), and (iv) submarine facies (<
1.6
ka: carbonate mud and shell hash lithofacies). The onset and duration of these sedimentary depositional environments are closely linked to Holocene sea-level rise in Bermuda, indicating that sea level controls environmental development in coastal karst basins. Finally, we present a conceptual model for interpreting the sediments and environments in coastal karst basins as a result of sea-level change.
► Sedimentation in coastal karst basins (CKBs) is poorly understood. ► We present the first complete Holocene succession from a Bermudian underwater cave. ► The cave evolved through four sedimentary depositional environments. ► Facies and environmental changes were driven by Holocene sea-level rise. ► A conceptual model describes environmental evolution in CKBs from sea-level change.
Caves are usually oligotrophic ecosystems, where the organic matter represents a limiting factor to the hypogeal community and sediments are often a significant energy source. With a view to ...identifying the energy input influencing the ecological processes occurring in caves, as well as the potential alteration sources of the natural equilibriums, geochemical features of several typologies of clastic sediments from the Pertosa-Auletta Cave (Italy) were investigated. The collected sediments, analyzed for a number of chemical (organic matter, Al, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, S, Si, Sr, Ti, V, Zn concentrations) and mineralogical (quartz, calcite, dolomite, clay minerals) characteristics, showed a different composition. Overall, their origin is supposed to be allochthonous, related to the important fluviokarst activities interesting the cave in the past, whereas the abundance of calcitic and dolomitic compounds can be autochthonous, being the carbonate the main host rock. The highest concentrations of organic matter, together with C, Cu, Mo, N, P, Pb, S and Zn, highlighted in one sample composed mainly of bats guano, revealed an important bioavailable energy input as well as a pollutant accumulation, mainly of anthropogenic origin.
Raponzolo is a paleo-phreatic cave explored in 2011 in the Brenta Dolomites (Trentino, Italy), at the remarkable altitude of 2,560 m a.s.l. Differently to all other caves of the area, it hosts ...well-cemented fine to medium sands of granitic-metamorphic composition. The composition suggests a sediment source from the Adamello and Tonale Unit, separated from the Brenta by one of the most important tectonic lineaments of the Alps (Giudicarie Line). The fine-sand sediment was sampled to determine burial time and thus a minimum age of the cave. Cosmogenic isotopes (
26
Al and
10
Be) in quartz grains allowed to estimate a minimum burial age of 5.25 Ma based on the mean sediment transport time at the surface and infer original altitude of the catchment area. Detrital apatite fission-track (AFT) and U-Pb dating on zircons provide information on the source, both from a regional and altitude (exhumation) perspective. Two populations of detrital AFT ages center at 17 (−2.3 + 2.6) Ma and 23 (−3.3 + 3.9) Ma, whereas the main detrital zircon U-Pb age populations are younger than 40 Ma. These correspond to intrusive and metamorphic sources nowadays outcropping exclusively above 2,200–2,300 m a.s.l. in Northern Adamello and Tonale. The results point to a late Miocene erosion and infilling of the cave by allochtonous sediments, with important implications on the timing of cave speleogenesis, as well as the paleogeographical connection, tectonic evolution and uplift of different structural units of the Alps. The roundness and the well sorted size of the quartz grains suggest a fluvial or aeolian origin, possibly recycled by glacial activity related to cold events reported in high latitude areas of the world at 5.75 and 5.51 Ma. These glacial phases have never been documented before in the Alps. This information confirms that the valleys dividing these geological units were not yet deeply entrenched during the onset of the Messinian Salinity Crisis (5.6–5.5 Ma), allowing an efficient transport of sediments across major tectonic lineaments of the Alps. This study shows the potential of cave sediments to provide information not only on the age of speleogenesis but also on the paleogeography of a wide area of the Alps during the late Miocene.
Sterkfontein Caves is the single richest early hominin site in the world with deposits yielding one or more species of
Australopithecus and possible early
Homo, as well as an extensive faunal ...collection. The inability to date the southern African cave sites accurately or precisely has hindered attempts to integrate the hominin fossil evidence into pan-African scenarios about human evolutionary history, and especially hominin biogeography. We have used U-Pb and U-Th techniques to date sheets of calcium carbonate flowstone inter-bedded between the fossiliferous sediments. For the first time, absolute age ranges can be assigned to the fossil-bearing deposits: Member 2 is between 2.8 ± 0.28 and 2.6 ± 0.30 Ma and Member 4 between 2.65 ± 0.30 and 2.01 ± 0.05 Ma. The age of 2.01 ± 0.05 Ma for the top of Member 4 constrains the last appearance of
Australopithecus africanus to 2 Ma. In the Silberberg Grotto we have reproduced the U-Pb age of ∼2.2 Ma of for the flowstones associated with StW573. We believe that these deposits, including the fossil and the flowstones, accumulated rapidly around 2.2 Ma. The stratigraphy of the site is complex as sediments are exposed both in the underground chambers and at surface. We present a new interpretation of the stratigraphy based on surface mapping, boreholes logs and U-Pb ages. Every effort was made to retain the Member system, however, only Members 2 and 4 are recognized in the boreholes. We propose that the deposits formally known as Member 3 are in fact the distal equivalents of Member 4. The sediments of Members 2 and 4 consisted of cone-like deposits and probably never filled up the cave. The U-Th ages show that there are substantial deposits younger than 400 ka in the underground cave, underlying the older deposits, highlighting again that these cave fills are not simple layer-cakes.
Although debris, loams and clays are usually regarded as typical cave sediments, loess and loess-like sediments are common among clastic cave deposits in the near-entrance facies of caves and rock ...shelters. Late Weichselian loess layers are very common in caves from the Kraków-Częstochowa Upland and were recognized in almost each excavated cave and rock shelter. These layers were initially dated to the LGM (Last Glacial Maximum), but new chronometric dating results are available that allow us to present a more detailed scheme of the geological age of the series.
This paper evaluates the significance of Polish in-cave loess layers as correlative horizons. We present the lateral and vertical stratigraphy and lithological variability of cave loesses and their usefulness as lithostratigraphic markers. These features are especially important for archeology and paleontology, as cave sediments, including loess, are usually the carriers of archeological and paleontological material.
•Cosmogenic nuclide burial dating of cave sediments in Liuchong River, southwestern China.•The embryonic form of modern Wujiang River was possibly presented at 0.75Ma ago.•The high river incision ...rate of northwest Guizhou Plateau is nearly ∼0.48m/ka.•Strong uplift of Tibetan Plateau in Quaternary might be the primary reason.•Others are due to the soluble carbonate bedrock and cut-through of Three Gorges.
Cosmogenic nuclides 10Be and 26Al have been analyzed for sediments from the multilevel riverside caves along the Liuchong River at the southeastern margin of the Tibetan Plateau. The Liuchong River is the northern origin of Wujiang River, which passes through the northwestern Guizhou Plateau and cuts down hundreds of meters into the bedrock, leaving behind an abundance of multilevel caves. The measured 26Al/10Be ratios produced the apparent burial ages in range of 0.49–2.85Ma. Taking into account of geomorphic and geological backgrounds, the Dashi Cave located at the highest level along the Liuchong River system formed around 0.75Ma ago, which probably suggests the initial formation age of the modern Wujiang River. The resulted incision rate of ∼480m/Ma in Guizhou in the last 0.75Ma is slightly higher than those in adjacent areas. This feature implies an intensive downcutting history of the Liuchong River during the Quaternary, which might be primarily caused by the uplift of Tibetan Plateau, cut-through of the Three Gorges and soluble carbonate bedrock.
The Guizhou Plateau represents a geomorphic transition between the Tibetan Plateau and the Yangtze River Plain. It likely formed in response to the propagation of surface uplift in southeastern Tibet ...during India-Eurasia continental collision. However, the uplift history of the region is unclear largely due to a lack of datable material. The bedrock geology is dominated by carbonate rocks, which contains numerous multi-level caves in the main river valleys that are linked to the river incision history. Cosmogenic 26Al and 10Be burial dating of sediments in caves and river terraces from the northwestern and southern plateau reveals the fluvial chronology and provides the first direct determination of long-term river incision rates. The caves and terraces on the Liuchong River in NW Guizhou yield burial ages of between 0.41 ± 0.12 Ma and 2.85 ± 0.21 Ma, indicating an average incision rate of 57 ± 3 m/Ma. Four level caves at Libo in southern Guizhou yield burial ages of between 0.56 ± 0.16 Ma and 3.54 (+0.25/-0.22) Ma, indicating slightly slower incision rate (47 ± 5 m/Ma). These new results imply that the high elevation of the Guizhou Plateau had developed before the Late Pliocene, and that surface uplift during the Late Cenozoic was largely uniform across the region.
Deciphering human activities in archaeological sites is a priority issue in archaeological studies, nevertheless its geochemical fingerprints on sediments are poorly known. In sites belonging to the ...recent prehistory these geochemical signals have been taken into account, but in oldest sites this subject has not been studied sufficiently.
The aim of this paper consists on tracking geochemical proxies that can be attributed to anthropogenic processes in endokarstic Pleistocene deposits. Recognize these elements can be a key factor in order to explore the potential of non-excavated archeological levels and find out activities performed in those sediments more accurately. For that purpose a Middle–Upper Pleistocene endokarstic deposit (Cueva del Ángel) belonging to the Iberian Peninsula has been chosen. This site provides numerous evidences of human activities, as butchering and cooking of predated animals or the habitual use of fire throughout its main stratigraphic sequence.
This geochemical/archaeological approach highlights that the upper units consist of anthropogenic influenced sediments, while the lower unit shows a greater percentage of geogenic inputs. Based on P and Zn–Cu–Sr, several levels with higher anthropogenic inputs have been identified. These two attributes can be suggested as proxies of human activities for this site. High values of P appear to be linked with “butchering highly occupied” levels, and high levels of Zn–Cu–Sr seem to be related with fires. This geochemical information has been compared and tested with previous archeological information.
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