Cosmogenic Nuclide Burial Dating Research Articles

The Chronology of Early Human Settlement in Three Gorges Region, China—Contribution of Coupled Electron Spin Resonance and Uranium-Series Dating Method

The Three Gorges region (TGR) located in the geographic center of China, is a transition zone between mountain and plain areas, and a probable migration corridor for hominins and other mammals between South and North China. Detailed chronological information of paleoanthropological evidence in this area could help us better understand the human evolution in East Asia. The OSL and U-series dating methods are two conventional dating methods generally adopted to date such sites; however, their applications were limited by the dating range—restricted to several hundred of millennia and ambiguous stratigraphic relationship between the archaeological remains and the dating target materials. Cosmogenic nuclide burial dating of quartzite stone artifacts and coupled electron spin resonance and uranium series dating (ESR/U-series) of fossil teeth have the potential to date Early–Middle Pleistocene hominin sites in Asia and were applied increasingly in China in recent years. However, the application of cosmogenic 26Al/10Be burial dating is limited in TGR because most sites are dominated by limestone, leading to the scarcity of the quartz component. In this case, the coupled ESR/U-series method plays a more important role in the establishment of the chronology of human settlement. In TGR, by using the coupled ESR/U-series method, we have dated seven important Early and Middle Pleistocene hominin settlement sites, including Longgupo, Jianshi, Yunxian, Meipu, Bailongdong, Changyang, and Yumidong sites. Based on our dating results, we propose that hominins were settled in TGR probably from the early stage of Early Pleistocene (∼2.5−2.2 Ma) at the Longgupo site to the late Middle Pleistocene to Late Pleistocene of the Yumidong site (∼274−14 ka) and very likely to spread to other parts of East Asia during this time period. In view of the potential of coupled ESR/U-series dating on fossil teeth from the hominin sites in the TGR, future work may consider the micro damage or non-destructive analysis of enamel fragment with the ESR method and laser ablation ICP-MS techniques that will make possible the direct dating of precious human fossils in China.

Fluvial evolution in a growing thrust-fold range of the Yumu Shan, NE Tibetan Plateau

In an active thrust-fold belt, the drainage evolution, such as the alternation between transverse and longitudinal rivers, will influence the surface erosion within the range and the sedimentary sequence in the foreland basin. However, knowledge of the controls of changes in transverse or longitudinal drainage patterns in an uplifting range is limited. The Yumu Shan, on the northeastern margin of the Tibetan Plateau, is an example for a young and active thrust-fold range that shows evidence for drainage reversals since ∼3 Ma. The materials we used are the late Cenozoic depositional sequences around the Yumu Shan. Analyses of the lithology, grain size, roundness, and clast orientation of gravel deposits on the northern and southern flanks, combined with the results of cosmogenic nuclide burial dating, reveal that a transverse river, the Liyuan River, crossed the Yumu Shan range during 3.0–1.8 Ma by eroding weak Cenozoic sedimentary rocks. After 1.8 Ma, however, this transverse river was deflected and flowed along the edge of the range, and a longitudinal river developed along the back flank of the range. This process was synchronous with the exposure of resistant Paleozoic rocks by the continuous uplift of the range. After comparison with other potential controlling factors for drainage reversals, such as variations in rock uplift, climate or upstream aggradation, we find that the change in bedrock resistance was the most likely control on the change from a transverse to a longitudinal drainage pattern in this relatively young thrust-fold belt. Furthermore, through comparison with a series of active fold-thrust belts worldwide, we propose a simple conceptual model for the drainage evolution of active fold-thrust belts. In the earlier stage of the uplift, the exposed soft sedimentary rocks will cause transverse (antecedent) rivers to cross the range. After the continuous uplift of the range, resistant rocks cause the deflection of a transverse river and its change to a longitudinal river along the back flank of the range. In the final stage, after the several million years to around ten million years of uplift, with the development of a mature range, the local base level of the foreland will greatly fall, promoting a return to a transverse drainage pattern by headward erosion and capture of longitudinal rivers.

Late Cenozoic channel migration of the proto-Yangtze River in the delta region: Insights from cosmogenic nuclide burial dating of onshore boreholes

A thorough magnetostratigraphic chronology of the Yangtze River Delta is problematic due to coarse-grained (i.e., poorly magnetized) deposits and sedimentary discontinuity. This study presents cosmogenic nuclide data which facilitate 26Al/10Be burial dating to determine the absolute age of horizons from four previously reported long onshore boreholes in the Yangtze Delta region that record sediment provenance change to the Yangtze River. Dates obtained close to the provenance change horizons in boreholes RGK15 and ZKJ39 from the northern delta were 4.99 (+1.26/−0.81) Ma and 4.74 (+0.94/−0.70) Ma, the oldest radiometric ages of borehole sediments yet to date. The provenance change horizon in boreholes LQ19 and LQ11 in the southern delta were dated to 0.94 (+0.17/−0.16) Ma and 0.57 ± 0.17 Ma, respectively. These new ages combined with previous lithofacies and provenance studies imply that the proto-Yangtze River first entered the northern delta prior to ~5 Ma, then migrated gradually southward to the present estuary location after 0.94 Ma and moved even further south at 0.57 Ma. The southward migration history of the proto-Yangtze River channel sheds lights not only on the tectonic subsidence widely occurring on the east China coast during the Quaternary, but also on the somewhat controversial connection history of the Yangtze River to the East China Sea.

Early Pleistocene climate-induced erosion of the Alaska Range formed the Nenana Gravel

Abstract The Pliocene-Pleistocene transition resulted in extensive global cooling and glaciation, but isolating this climate signal within erosion and exhumation responses in tectonically active regimes can be difficult. The Nenana Gravel is a foreland basin deposit in the northern foothills of the Alaska Range (USA) that has long been linked to unroofing of the Alaska Range starting ca. 6 Ma. Using 26Al/10Be cosmogenic nuclide burial dating, we determined the timing of deposition of the Nenana Gravel and an overlying remnant of the first glacial advance into the northern foothills. Our results indicate that initial deposition of the Nenana Gravel occurred at the onset of the Pleistocene ca. 2.34 Ma and continued until at least ca. 1.7 Ma. The timing of initial deposition is correlative with expansion of the Cordilleran ice sheet, suggesting that the deposit formed due to increased glacial erosion in the Alaska Range. Abandonment of Nenana Gravel deposition occurred prior to the first glaciation extending into the northern foothills. This glaciation was hypothesized to have occurred ca. 1.5 Ma, but we found that it occurred ca. 0.39 Ma. A Pleistocene age for the Nenana Gravel and marine oxygen isotope stage 10 age for the oldest glaciation of the foothills necessitate reanalysis of incision and tectonic rates in the northern foothills of the Alaska Range, in addition to a shift in perspective on how these deposits fit into the climatic and tectonic history of the region.

Progressive back-warping of a rider block atop an actively exhuming, continental low-angle normal fault

Can continental low-angle normal faults (LANFs) initiate and remain active at shallow (<30°) dips? The Mai'iu-Gwoira fault system is an active, large-displacement detachment fault in SE Papua New Guinea.Although the Mai'iu fault is still active in the west, to the east it dips 15–22° at the surface, and has been abandoned in favor of the younger, 42 ± 7° dipping Gwoira fault. Fault abandonment has caused part of the former hanging wall to be captured by the footwall. This rider block's structure records progressive shallowing of the Mai'iu fault concurrent with slip.We present 26Al/10Be cosmogenic nuclide burial dating; along with a recently published (U–Th-Sm)/He apatite and zircon age, these provide the first direct dating of the Gwoira conglomerate. These data imply inception of the Mai'iu fault before 3.12–6.04 Ma, and inception of the Gwoira fault between 2.29 and 5.62 Ma.Bedding fault cut-off angles suggest the Mai'iu fault did not initiate as a LANF. Rather, it initially dipped >44° at the surface, and was subsequently back-rotated while active to its present 15–22° surface dip. This suggests that continental LANFs initiate at moderate dips, and evolve according to the ‘rolling-hinge’ process.

Cosmogenic nuclide burial dating of Liuwan Paleolithic site in the Luonan Basin, Central China

The Luonan Basin is a key region of early human settlement in Central China with more than 300 discovered Paleolithic sites. Artifact layer 1 of the Liuwan site was dated to approximately 0.6 million years (Ma) based on correlation with the well-dated loess–paleosol sequence of the central Chinese Loess Plateau. This study reassessed the age of the Liuwan artifact layer via an absolute dating method, namely, 26Al/10Be burial dating. We determined the burial age of artifact layer 1, which was most likely at least 0.60 ± 0.12 Ma (1ơ), using three simple burial ages. The new burial age confirmed the previous estimated age and provided a considerably accurate age range. Therefore, we suggest the use of the 26Al/10Be burial dating method in thin loess-covered Paleolithic sites around the Qinling Mountain Range is helpful to understand the early human behavior.

Mid-Miocene cosmogenic upper limit for 10Be/21Ne burial age

Abstract Cosmogenic nuclide burial dating provides an alternative method for sediment dating, and the combination of radionuclide 10Be with noble gas isotope 21Ne would theoretically extend the burial dating range up to around 15 Ma ago, which endows 10Be/21Ne pair with huge potential in middle-Miocene sediment dating. Especially in the magnetostratigraphic studies of the Cenozoic sedimentary strata, the 10Be/21Ne pair could be expected to provide absolute age marker when the well-dated volcanic ash layer or bedded mammalian fossils are absent. However, the validity and accuracy of the 10Be/21Ne burial dating when used close to its limiting middle Miocene ages has not been assessed in case study. Here, we show our dating results of the sedimentary stratum samples, which deposited at the same bedding of the Vertebrate fossils of Platybelodon tongxinensis that offer an independent age constraint between 12 and 15 Ma. The 10Be/21Ne analyses yielded a mean burial age of 13.25 ± 0.33 Ma, which agrees well with the paleontological proxy, and the MSWD value of 0.66 indicates the good agreement of the apparent dispersion of six aliquots data with their individual measurement errors. In view of the extended applicable dating range of 10Be/21Ne pair, it is promising in providing absolute age marker or valuable chronological information for a variety of fields in Earth science and beyond.

Geochronological investigations using a combination of luminescence and cosmogenic nuclide burial dating of drill cores from the Vienna Basin

Geochronological investigations using a combination of luminescence and cosmogenic nuclide burial dating of drill cores from the Vienna Basin

Cosmogenic nuclide burial dating of an alluvial conglomerate sequence: An example from the Hexi Corridor, NE Tibetan Plateau

Abstract The thick alluvial conglomerate sequences around the Tibetan Plateau have been notoriously difficult to date. Here we use the cosmogenic nuclide burial dating method to date the Yumen and Jiuquan formations, a ∼900 m thick fanglomerate found in the Hexi Corridor, the foredeep of the Qilian Shan, and exposed in the Laojunmiao anticline. We date 16 sites with simple burial dating and 2 sites with isochron burial dating, and use these dates to reinterpret the magnetostratigraphy of the section. We suggest that the bottom of the Yumen Formation, defined by a progressive unconformity, is around 5 My. Taking this timing as the initiation of anticline growth, the long-term crustal shortening rate at the ramp zone in western Qilian Shan is about 0.72 mm/yr, consistent with those obtained from middle and eastern Qilian Shan. The boundary between the Yumen and Jiuquan Formations is near ∼1.2 My. Three other angular unconformities are dated to ∼2.6–3.1, ∼2.2–2.5, and ∼1.2–1.7 My, respectively. Burial dating offers a robust chronology for these deposits, and when combined with paleomagnetic stratigraphy offers much tighter precision.

Two million years of river and cave aggradation in NE Brazil: Implications for speleogenesis and landscape evolution

This study characterizes and provides ages for an extensive sedimentary record occurring in Lapa Doce and Torrinha caves, NE Brazil. With >40km of surveyed passages, these caves integrate a distributary cave system fed by allogenic recharge from the surrounding sandstone plateaus. Sediment petrography together with descriptions of depositional facies and architectural elements shows four depositional units related to fluvial and standing water environments. These include, from bottom to top: (1) a channel unit including lateral bars deposited during an ordinary flood regime; (2) a sandy flood unit including minor channel and scour fills derived from bank-full equivalent flood events; (3) mud caps deposited in standing water that often reach the ceiling; and (4) intraclast breccias associated with collapse of the mud caps under saturated conditions. The deposits were dated using a combination of cosmogenic nuclide burial dating and U-series dating of flowstone. Cosmogenic nuclide data point to fluvial aggradation being active since 1.91+0.12My and extending until 0.36±0.08My, with intensive cave and valley aggradation events between 0.78±0.10My and 0.44±0.12My. Long term alluviation of the cave system seems to be important in forming passages, determining their configuration, and setting up a general distributary pattern evident in passage morphology and sedimentary sequences. Mud caps overlapping the fluvial deposits are interpreted as the products of successive rising and lowering of the water table (static level). Radiometric ages of interstratified flowstones and speleothems show that these oscillations were active at least since 115ky ago and finally ceased around 12ky ago, indicated by the recurrent age obtained from uneroded capping flowstones. These long-term water table oscillations may drive paragenetic expansion of the whole cave system. Valleys, caves and other landforms in our study area are part of an ancient landscape with multiple episodes of burial and exhumation. Despite the possibility of much older sediment being preserved somewhere in the cave system, our data indicate a younger Quaternary age for the bulk of the sediment filling the study caves.

Lake George revisited: New evidence for the origin and evolution of a large closed lake, Southern Tablelands, NSW, Australia

Lake George contains the longest continuous sedimentary record of any Australian lake basin, but previous age models are equivocal, particularly for the oldest (pre-Quaternary) part of the record. We have applied a combination of cosmogenic nuclide burial dating, magnetostratigraphy and biostratigraphy to determine the age of the basal (fluvial) unit in the basin, the Gearys Gap Formation. Within the differing resolutions achievable by the three dating techniques, our results show that (i) the Gearys Gap Formation, began accumulating at ca 4 Ma, in the early Pliocene (Zanclean), and (ii) deposition had ceased by ca 3 Ma, in the mid late Pliocene (Piacenzian). Whether the same age control provides an early Pliocene (Zanclean) age for the formation of the lake basin is uncertain. During the Piacenzian, the vegetation at the core site was a wetland community dominated by members of the coral fern family Gleicheniaceae, while the surrounding dryland vegetation was a mix of sclerophyll and temperate rainforest communities, with the latter including trees and shrubs now endemic to New Guinea–New Caledonia and Tasmania. Mean annual rainfall and temperatures are inferred to have been ∼2000–3000 mm, although probably not uniformly distributed throughout the year, and within the mesotherm range (>14°C <20°C), respectively. Unresolved issues are: (1) Does the basal gravel unit predate uplift of the Lake George Range and therefore provide evidence that one of the proposed paleo-spillways of Lake George, that above Geary's Gap, has been elevated up to 100–200 m by neotectonic activity over the past 4 million years? (2) Did a shallow to deepwater lake exist elsewhere in the lake basin during the Pliocene?

Cosmogenic nuclide burial dating of hominin-bearing Pleistocene cave deposits at Swartkrans, South Africa

Based on the cosmogenic nuclide burial dating technique, we present new radiometric age estimates of 2.19 ± 0.08 and 1.80 ± 0.09 million-years-old (Ma) for Member 1, and 0.96 ± 0.09 Ma for Member 3 of the Swartkrans Formation in South Africa. Our data are consistent with, and expand upon, results from previous radiometric dating techniques used at the site. The burial ages of Member 1 are consistent with the uranium–lead (U–Pb) age provided by bracketing flowstones (Pickering et al., 2011), while the age of Member 3 is significantly more precise than the large age bracket provided by U–Pb dating of tooth enamel (Balter et al., 2008) and recently re-evaluated electron spin resonance data (Herries and Adams, 2013). These new dates provide the complete age range for the extinct hominin, Paranthropus robustus, as well as indicate the first appearance of the genus Homo in southern Africa. Our results also indicate: the first, as well as the last, manufacture and use of bone digging tools in South Africa; some of the earliest evidence of stone tool use and large animal butchery in South Africa; and one of the earliest archaeological indications of the domestication of fire in the world.

Cosmogenic nuclide burial age of the Sanying Formation and its implications

The Pliocene fluvial/lacustrine sediments of the Sanying Formation lie along the Red River fault and its northwest extension; their majority outcrops appear around Eryuan. The Sanying Formation is characterized by multiple intercalated coal layers and its unconformities contact with the underlying Triassic limestone and the overlying Quaternary coarse sediments. Cosmogenic nuclide burial dating confirms the Pliocene age of the Sanying Formation. The burial ages of the overlying Quaternary sediments provide the lower age limit of the Sanying Formation: 2 Ma. Detrital zircon U-Pb age distribution suggests provenance of the Sanying Formation traced to the Songpan-Ganzi flysch belt. From the spatial distribution as well as sedimentary and fault ages, we found a strong connection of the Sanying Formation with the Red River and the Jianchuan faults. We therefore propose that activation of the Red River and the Jianchuan faults during the Late Miocene resulted in subsidence of basins in the extensional areas around Eryuan and in the middle to south segments of the Red River fault. The basins were filled with water carried by the Jinsha River and overflow-lakes formed within the basins where the Sanying Formation was deposited. Most of the lakes were dried and sedimentation of the Sanying Formation ceased due to the uplift of the Yunling Mountains, which forced rerouting of the Jinsha River at the beginning of Quaternary.

Time constraints for the Yellow River traversing the Sanmen Gorge

The Yellow River is the second longest river in China, a total course of 5464 km. The Yellow River traverses 30 gorges within its main course and the last one is the Sanmen Gorge. The timing of cut through the Sanmen Gorge indicates the final integration of the Yellow River. Previous geological surveys identify a paleolake in the Weihe Basin located west of the Sanmen Gorge; the lake was drained when the gorge was cut through. Using cosmogenic nuclide burial dating, we obtain ages of transition from lake to fluvial environments in the Weihe Basin and formation of fluvial terraces within the Sanmen Gorge. The timing of cut through the Sanmen Gorge is constrained to 1.3–1.5 Ma. Zircon U‐Pb age distributions further suggest that the Weihe, the largest tributary of the Yellow River running from west to east along the northern section of the Qinling Mountains, primarily flowed over the Sanmen Gorge, followed by the upper and middle Yellow River traversing 1.3–1.4 Ma ago. It appears that formation and integration of the Yellow River occurred in a short duration in the early Pleistocene, probably related to global climate changes.

Improving cosmogenic-nuclide burial dating

Improving cosmogenic-nuclide burial dating

The dating and interpretation of a Mode 1 site in the Luangwa Valley, Zambia

Flake based assemblages (Mode 1) comprise the earliest stone technologies known, with well-dated Oldowan sites occurring in eastern Africa between ∼ 2.6-1.7 Ma, and in less securely dated contexts in central, southern and northern Africa. Our understanding of the spread and local development of this technology outside East Africa remains hampered by the lack of reliable numerical dating techniques applicable to non-volcanic deposits. This study applied the still relatively new technique of cosmogenic nuclide burial dating ( 10Be/ 26Al) to calculate burial ages for fluvial gravels containing Mode 1 artefacts in the Luangwa Valley, Zambia. The Manzi River, a tributary of the Luangwa River, has exposed a 4.7 m deep section of fluvial sands with discontinuous but stratified gravel layers bearing Mode 1, possibly Oldowan, artefacts in the basal layers. An unconformity divides the Manzi section, separating Mode 1 deposits from overlying gravels containing Mode 3 (Middle Stone Age) artefacts. No diagnostic Mode 2 (Acheulean) artefacts were found. Cosmogenic nuclide burial dating was attempted for the basal gravels as well as exposure ages for the upper Mode 3 gravels, but was unsuccessful. The complex depositional history of the site prevented the calculation of reliable age models. A relative chronology for the full Manzi sequence was constructed, however, from the magnetostratigraphy of the deposit (N>R>N sequence). Isothermal thermoluminescence (ITL) dating of the upper Mode 3 layers also provided consistent results (∼78 ka). A coarse but chronologically coherent sequence now exists for the Manzi section with the unconformity separating probable mid- or early Pleistocene deposits below from late Pleistocene deposits above. The results suggest Mode 1 technology in the Luangwa Valley may post-date the Oldowan in eastern and southern Africa. The dating programme has contributed to a clearer understanding of the geomorphological processes that have shaped the valley and structured its archaeological record.

Early Acheulean technology in the Rietputs Formation, South Africa, dated with cosmogenic nuclides

An absolute dating technique based on the build-up and decay of 26Al and 10Be in the mineral quartz provides crucial evidence regarding early Acheulean hominid distribution in South Africa. Cosmogenic nuclide burial dating of an ancient alluvial deposit of the Vaal River (Rietputs Formation) in the western interior of South Africa shows that coarse gravel and sand aggradation there occurred ca 1.57 ± 0.22 Ma, with individual ages of samples ranging from 1.89 ± 0.19 to 1.34 ± 0.22 Ma. This was followed by aggradation of laminated and cross-bedded fine alluvium at ca 1.26 ± 0.10 Ma. The Rietputs Formation provides an ideal situation for the use of the cosmogenic nuclide burial dating method, as samples could be obtained from deep mining pits at depths ranging from 7 to 16 meters. Individual dates provide only a minimum age for the stone tool technology preserved within the deposits. Each assemblage represents a time averaged collection. Bifacial tools distributed throughout the coarse gravel and sand unit can be assigned to an early phase of the Acheulean. This is the first absolute radiometric dated evidence for early Acheulean artefacts in South Africa that have been found outside of the early hominid sites of the Gauteng Province. These absolute dates also indicate that handaxe-using hominids inhabited southern Africa as early as their counterparts in East Africa. The simultaneous appearance of the Acheulean in different parts of the continent implies relatively rapid technology development and the widespread use of large cutting tools in the African continent by ca 1.6 Ma.