Fossil-bearing Layers Research Articles

Calibrating the Jehol Biota in the Baiwan Basin of the North Qinling Orogenic Belt, central China

The Jehol Biota sensu lato has a very wide distribution in East Asia, providing palaeontological clues for recovering the Early Cretaceous terrestrial ecosystems. This Biota was considered to reach the Qinling Orogenic Belt but its reaching time remains unclear. In this study, we initially constrained the age of the Jehol Biota recovered from the Baiwan Formation of the Baiwan Basin, Zhenping County, southwestern Henan Province, which geographically lies in the North Qinling Orogenic Belt. LA-ICP-MS U–Pb analyses were conducted for the fossil-bearing layers, providing a maximum depositional age of ca. 123.6 Ma (early Aptian). This age is consistent with the biostratigraphic analyses, and can approximately constrain the fossil-bearing layers. This study confirmed that the Jehol Biota has already reached the Qinling Orogenic Belt during its secondary evolutionary stage, revealing the unique palaeogeographic position of this belt for the dispersal of the Jehol Biota in East Asia.

A paleoenvironmental and ecological analysis of biomarkers from the Eocene Fossil Basin, Green River Formation, U.S.A.

Exceptionally well-preserved fossil specimens in the Fossil Basin of the Green River Formation (GRF) have made it the subject of extensive paleontological study, but the organic molecular framework that evolved during a key paleoclimatic and fossil-bearing interval during the early Eocene is poorly understood. Whereas the organic geochemistry of the larger co-eval GRF basins has been extensively characterized, our molecular understanding of the fossil-bearing layers in the Fossil Basin and the drivers of the exceptional fossilization therein remain unresolved. To bridge this gap, sediments from the famous 18″-layer — the fossiliferous horizon that is extensively quarried for exceptional soft-tissue fossils — were sampled for organic and isotopic geochemical characterisation. The results show that the Fossil Basin sedimentary archive is geochemically distinct from other GRF basins, as exemplified by the absence of the classical biomarker β-carotane and minimal evidence for the large green algal blooms that predominate in the other GRF lake basins. Photic zone euxinia (PZE), anoxia, and a freshwater cap enabled development of a productive and diverse ecosystem. Salinity and density stratification prevented vertical mixing of the water column and supported preservation of decaying carcasses. In contrast to other GRF basins, the small areal extent and ellipsoid shape of the Fossil Basin focussed terrestrial and freshwater inputs into the lake, resulting in ideal conditions for preservation of an exceptional fossil record.

Challenging the antiquity of the Cradle of Humankind, South Africa: Geochronological evidence restricts the age of Eurotomys bolti and Parapapio to less than 2.3 Ma at Waypoint 160, Bolt's Farm

Waypoint 160 is a paleocave at Bolt's Farm in the ‘Cradle of Humankind,’ South Africa. It is known for the novel murid taxa Eurotomys bolti, argued to be morphologically intermediate between Eurotomys pelomyoides from Langebaanweg (∼5.1 Ma) and the earliest Otomyinae from Makapansgat Limeworks (∼3.0–2.6 Ma). Based on the presence of this specimen, an age of ∼4.5 Ma was inferred for Waypoint 160, making it far older than other Cradle sites. This biochronological age was used to argue that Parapapio and Cercopithecoides fossils from Waypoint 160 were the oldest in the region. Here, we provide a detailed sedimentological context for the in-situ deposits at Waypoint 160. We have identified interior cave deposits, in contrast to other sites at Bolt's Farm. Petrography confirms that one unit (facies D) contains in-situ microfaunal fossils, indicating the likely provenience of the E. bolti specimen. Palaeomagnetic analysis shows four periods of magnetic polarity in the sequence. Using U–Pb ages as chronological pins, we argue that the upper part of the sequence records a polarity change at the end of the Olduvai subChron (1.78 Ma). The lower part of the sequence records a polarity shift from normal to reversed that likely relates to the Feni subChron (2.16–2.12 Ma), based on a basal flowstone U–Pb age of 2.269 ± 0.075 Ma. Together this points to a depositional window of ∼500 ka, with the Parapapio and E. bolti tentatively attributed to the micromammal fossil-bearing layers dating to ∼2.27–2.07 Ma. This has significant implications for other biochronological dates in South Africa, as E. bolti is now less than ∼2.27 Ma, younger than the oldest Otomyinae at Makapansgat Limeworks and thus not ancestral to them. This chronology for Waypoint 160 challenges the presence of older, early to mid-Pliocene deposits >3.20 Ma in the Gauteng portion of the Cradle.

Revised age and stratigraphy of the classic Homo erectus-bearing succession at Trinil (Java, Indonesia)

Obtaining accurate age control for fossils found on Java (Indonesia) has been and remains challenging due to geochronologic and stratigraphic uncertainties. In the 1890s, Dubois excavated numerous faunal fossils—including the first remains of Homo erectus—in sediments exposed along the Solo River at Trinil. Since then, various, and often contradictory age estimates have been proposed for the Trinil site and its fossils. However, the age of the fossil-bearing layers and the fossil assemblage remains inconclusive. This study constructs a chronostratigraphic framework for the Trinil site by documenting new stratigraphic sections and test pits, and by applying 40Ar/39Ar, paleomagnetic, and luminescence (pIRIR290) dating methods. Our study identifies two distinct, highly fossiliferous channel fills at the Trinil site. The stratigraphically lower Bone-Bearing Channel 1 (BBC-1) dates to 830–773 ka, while Bone-Bearing Channel 2 (BBC-2) is substantially younger with a maximum age of 450 ± 110 ka and an inferred minimum age of 430 ± 50 ka. Furthermore, significantly younger T2 terrace deposits are present at similar low elevations as BBC-1 and BBC-2. Our results demonstrate the presence of Early and Middle Pleistocene, and potentially even late Middle to Late Pleistocene fossiliferous sediments within the historical excavation area, suggesting that Dubois excavated fossils from at least three highly fossiliferous units with different ages. Moreover, evidence for reworking suggests that material found in the fossil-rich strata may originate from older deposits, introducing an additional source of temporal heterogeneity in the Trinil fossil assemblage. This challenges the current assumption that the Trinil H.K. fauna –which includes Homo erectus-is a homogeneous biostratigraphic unit. Furthermore, this scenario might explain why the Trinil skullcap collected by Dubois is tentatively grouped with Homo erectus fossils from Early Pleistocene sediments at Sangiran, while Trinil Femur I shares affinities with hominin fossils of Late Pleistocene age.

Evidence for the latest fossil Pongo in southern China

Pongo fossils with precise absolute age brackets are rare, limiting our understanding of their taxonomy and spatiotemporal distribution in southern China during the Late Pleistocene. Twenty-four isolated teeth of fossil orangutans were recently discovered during excavations at Yicun Cave in Guangxi Zhuang Autonomous Region, southern China. Here, we dated the fossil-bearing layer using Uranium-series dating of the associated flowstone and soda straw stalactites. Our results date the Yicun orangutan fossils to between 66 ± 0.32 ka and 57 ± 0.26 ka; thus, these fossils currently represent the last appearance datum of Pongo in southern China. We further conducted a detailed morphological comparison of the Yicun fossil teeth with large samples of fossil (n = 2454) and extant (n = 441) orangutans from mainland and island Southeast Asia to determine their taxonomic position. Compared to other fossil and extant orangutan samples, the Yicun Pongo assemblage has larger teeth and displays greater variation in occlusal structure. Based on the high frequency of cingular remnants and light to moderate enamel wrinkling of the molars, we assigned the Yicun fossils to Pongo weidenreichi, a species that was widespread in southern China throughout the Pleistocene. Lastly, we used published stable carbon isotope data of Early to Late Pleistocene mammalian fossil teeth from mainland Southeast Asia to reconstruct changes in the paleoenvironment and to interpret dental size variation of Pongo assemblages in a broader temporal and environmental context. The carbon isotope data show that dental size reduction in Pongo is associated with environmental changes. These morphological changes in Pongo appear to coincide with the expansion of savannah biomes and the contraction of forest habitats from the Middle Pleistocene onward. The variation in dental size of forest-dwelling Pongo in mainland Southeast Asia may have resulted from habitat differentiation during the Pleistocene.

Isochron 26Al/10Be burial dating of the Xiashagou Fauna in the Nihewan Basin, northern China: Implications for biogeography and early hominin dispersals

The Nihewan Basin in northern China is one of the most dense occurrences of Early Pleistocene vertebrate paleontological and Paleolithic sites outside of Africa and thus plays a key role in the study of biochronostratigraphy and early human evolution in East Asia. The Xiashagou Fauna, as the first systematically studied fauna in the basin, is usually referred to as the Nihewan Fauna (sensu stricto) and is considered the Early Pleistocene type fauna in northern China, serving as a key reference for biostratigraphical correlations. The Xiashagou Fauna was initially correlated with the Olivola Fauna of early Late Villafranchian age in Europe, dated to ∼1.8 Ma. It has been more recently constrained to the Matuyama chron between the Réunion and Olduvai subchrons, with an estimated age range of 2.2–1.7 Ma. However, there is still an absence of absolute dates associated with this important Fauna. Here, the isochron 26Al/10Be burial dating method was used to radio-isotopically verify the biostratigraphic and magnetostratigraphic age of the Xiashagou Fauna. Two sets of quartzose clasts were collected from the cross-sections near Xiashagou. The isochron burial age of six samples from one of the fossil-bearing layers is 2.05 ± 0.38 (0.39) Ma (bracketed uncertainty includes external systematic errors, ±1σ), in agreement with previous paleomagnetic estimates of 2.2–1.7 Ma. The isochron age of another five samples from a gravel layer about 80 m below the sampled fossil layer and 55 m beneath the deepest buried fossil layer is 2.43 ± 0.16 (0.18) Ma (±1σ), in agreement with previous paleomagnetic estimates of 2.58 Ma. Our results show that the age of the Xiashagou Fauna is consistent with the updated ages (2.21–1.95 Ma) of the Senèze and Olivola Faunas in Europe. The potential existence of an ecological corridor for faunal dispersals across northern Eurasia during this time period should be important to help contextualize the nature of the earliest hominin dispersals into and across Eurasia. As the first radio-isotopic ages for the Nihewan Basin sites, our results provide independent age control to anchor the magnetostratigraphy of the Early-Middle Pleistocene strata in the Nihewan Basin and to calibrate the Early Pleistocene stage of the Chinese Quaternary.

The exceptionally preserved Early Cretaceous “Moqi Fauna” from eastern Inner Mongolia, China, and its age relationship with the Jehol Biota

New fossil-bearing horizons at the Gezidong and Jiaxikou localities, eastern Inner Mongolia, referred to as the Moqi fossil bed, yield a diverse fossil assemblage coined herein as “Moqi Fauna”. The Moqi Fauna provides important insights into the evolution of some vertebrate clades, such as frogs and salamanders, and their Early Cretaceous diversification. In this paper, we report an improved chronology of the Moqi fossil bed based on SIMS and high-precision CA-ID-IRMS U-Pb zircon analyses of three tuff samples from horizons that are interstratified with the fossil-bearing layer at two localities. The SIMS U-Pb dating method applied on zircons from three samples gave dates of 117.8 ± 0.9/1.5 Ma, 117.7 ± 1.0/1.5 Ma, and 118.3 ± 1.2/1.7 Ma, respectively. Two high-precision CA-ID-IRMS U-Pb weighted mean 206Pb/238U ages of, 119.20 ± 0.38/0.38/0.72 Ma and 118.67 ± 0.13/0.14/0.28 Ma were also obtained. These findings indicate the age of the Moqi Fauna is ca. 119.20 Ma to 118.67 Ma. Comparison of the Moqi Fauna with the well-known Jehol Biota, as well as the Fuxin Biota of a slightly younger age, suggests that the Moqi Fauna was a distinct fauna which shows a potential link with the Jehol Biota.

New geochronological constraints for the Lower Cretaceous Jiufotang Formation in Jianchang Basin, NE China, and their implications for the late Jehol Biota

The Lower Cretaceous Jiufotang Formation in western Liaoning Province, northeastern China contains important vertebrate fossils of the late Jehol Biota, e.g., the four-winged non-avian dinosaur Microraptor . This formation documents the late phase of the Jehol Biota, producing the most abundant fossil records of the Mesozoic birds. However, the precise age constraints on the fossiliferous layers of this formation remain scarce and chronological consensus of this formation has not been reached, limiting our understanding of the evolutionary history of the Jehol Biota and its time-spatial distribution. Here we present secondary ion mass spectrometry (SIMS) U-Pb zircon analysis results of four tuff samples interbedded within the Jehol fossil-bearing layers from the Jiufotang Formation outcrops at the Sanmendian and Xiaotaizi sections in the Jianchang Basin, western Liaoning. Stratigraphic correlation between two outcrop sections is achieved by combining lithostratigraphic, biostratigraphic, and SIMS U-Pb zircon dating results. One tuff bed SMD17-1 closed to the boundary of the Yixian/Jiufotang formations from the Sanmendian section yielded an age of 122.0 ± 0.9 Ma, and three tuff beds XTZ17-1, XTZ17-2, and XTZ17-3 from the Xiaotaizi section dated to 118.9 ± 0.8 Ma, 118.8 ± 0.6 Ma, and 118.6 ± 1.1 Ma, respectively. These ages suggest that the Jiufotang Formation in Jianchang Basin was deposited at ca. 122.0–118.9 Ma, the latest Barremian–Aptian stage of the Lower Cretaceous and provides stringent constraints on the Mesozoic vertebrates discovered in the Jianchang Basin. Furthermore, the late Jehol Biota documents in the Jiufotang Formation has been placed between ~123 and ~119 Ma based on our new chronology and previous radiometric dates. It is critical to evaluate the evolutionary history of various important Mesozoic taxa discovered from the Jehol Biota and explore the patterns and modes of major vertebrate lineages documented in this interval. • • We report a new chronology from the Jiufotang Formation in Jianchang Basin, NE China. • • The fossiliferous horizons have precisely constrained to 122.0–118.9 Ma. • • Age calibration for the diversification of mammals and birds of late Jehol Biota. • • Updated age of the Jiufortang Formation for Palaeobiology Database ( paleodb.org /).

A new vertebrate fossil-bearing layer in the Rhætelv Formation (Kap Stewart Group) of central East Greenland: evidence of a Hettangian marine incursion into the continental Jameson Land Basin

A new vertebrate fossil-bearing layer in the Rhætelv Formation (Kap Stewart Group) of central East Greenland: evidence of a Hettangian marine incursion into the continental Jameson Land Basin

A benthic oxygen oasis in the early Neoproterozoic ocean

Benthic oxygen oases linked to photosynthetic mats have been reported in modern anoxic aquatic systems. Benthic macroalgal blooms were common in stratified, anoxic Neoproterozoic oceans, leading us to hypothesize the existence of benthic oxygen oases at that time. This hypothesis has significant implications regarding the bioavailability of transition metals (e.g., Cu, Zn, Ni, Mo, V) and the distribution of aerobic eukaryotes in these oceans. However, little research has been directed toward testing the benthic oxygen oasis hypothesis in ancient anoxic marine systems. In this contribution, we report on an integrated investigation of iron speciation, trace elements, and carbon–sulfur-δ34Spy for the Tonian Longfengshan Biota-bearing versus non-fossil-bearing shales of the Luotuoling Formation in the Longfengshan section of the Yanshan Basin (North China). Typical marine B/Ga values (6.5–7.3) suggest that the Yanshan Basin was fully marine and well connected with the open ocean. The low FeHR/FeT ratios of the non-fossiliferous intervals (mean 0.14) suggest oxic water-column conditions during their deposition, and their FeHR pool contains significant amounts of pyrite and siderite (up to 44%), implying their formation in underlying reducing sedimentary porewaters. In contrast, the fossil-bearing layers show high and oscillating FeHR/FeT ratios (mean 0.39; up to 0.51) and systematically low Fepy/FeHR (mean ~0), suggesting dominantly ferruginous water-column conditions with redox oscillation. Furthermore, lack of redox sensitive trace-metal and sulfide enrichments and dominance of the FeHR pool by ferric oxide and magnetite (96–100%) indicate substantially oxidative power in the reducing water-column and underlying surface sediments. In combination with coexisting sedimentological and paleontological data, these conflicting and contrasting redox signals can be best interpreted by the development of benthic oxygen oases in deeper reducing waters, regulated by the Neoproterozoic benthic macroalga Longfengshaniaceae most likely in association with microbial/cyanobacterial mats, which contributed the oxidative power in the reducing environments. Our findings provide new insights into early Neoproterozoic oceanic redox conditions, iron cycling and the evolution of early aerobic eukaryotes, including animals.

Living in a time of change: Late Pleistocene/Holocene transitional vertebrate fauna of Grot Skeliastyi (Crimea, Ukraine)

ABSTRACT The paper presents the results of the study of vertebrate fossil assemblages recovered from the Grot Skeliastyi rock shelter in south-western Crimea (Ukraine). The deposition of its fossil-bearing layers covers the time span from the Late Glacial to the early Holocene. The studied sample consists of 2,736 bones belonging to 52 species of vertebrates (including 3 fishes, 1 amphibian, 12 reptiles, 10 birds, 26 small and large mammals). Among them, the past presence of the Aesculapian snake, four-lined ratsnake, squacco heron, tree pipit, and water pipit in the region is here documented for the first time. Extinct taxa in the faunal assemblage of Grot Skeliastyi were represented by wild horse, European ass, steppe bison, and woolly mammoth. Remains of small animals were accumulated due to the feeding activity of the eagle owl, while bones of large mammals could have been a part of the prey of carnivores but mostly are associated with the hunting activity of ancient people who inhabited the rock shelter. Most of the species persisted from the Pleistocene to the Holocene without losses. Our results indicate that the Pleistocene/Holocene transition in Crimea was not characterised by drastic faunal changes unlike those in other parts of Eastern Europe.Not StartedCompletedRejected

SIMS U-Pb geochronology for the Jurassic Yanliao Biota from Bawanggou section, Qinglong (northern Hebei Province, China)

ABSTRACT The Yanliao Biota is notable for producing rare and well-preserved Jurassic vertebrate fossils. Many discoveries in the Bawanggou section, northern Hebei Province have greatly enhanced our knowledge of important vertebrate fossils from the Yanliao Biota, including an arboreal euharamiyidan mammal, maniraptoran theropods, salamanders and pterosaurs. However, lacking of precise dating for the sediments bearing these fossils in the Bawanggou section hampered further understanding of the evolution of this biota. Here we report a chronology based on secondary ion mass spectrometry (SIMS) U-Pb zircon analyses from the Tiaojishan Formation bearing the Yanliao Biota in the Bawanggou section. Three bentonite layers dated to 159.0 ± 1.1 Ma, 159.5 ± 0.8 Ma, and 159.8 ± 0.8 Ma, respectively, were found to be interstratified with the fossil-bearing layer in this area. These data place the Yanliao Biota from Qinglong in the Oxfordian Stage of the Upper Jurassic and provide stringent constraints on vertebrates discovered in the Bawanggou section. Previous biostratigraphic studies and our geochronology show that fossil assemblage in the Bawanggou section is coeval with the Linglongta Biota (late Yanliao Biota) preserved in the Daxishan section (western Liaoning Province).

Correlation of carbon isotope stratigraphy and paleoenvironmental conditions in the Cretaceous Jehol Group, northeastern China

ABSTRACTThe Jehol Biota represents an important phase in the history of biological evolution on Earth. Two sites with Aptian Jehol Biota, located in western Liaoning Province and in northern Hebei Province, northeastern China, have generated a major debate about the relationships between their fossil-bearing layers, resulting in confusions about their stratigraphic correlation and biogenetic sequence. We have applied carbon isotope analysis of total organic carbon to provide new data relevant to this debate and have re-examined the connection between volcanism and carbon cycle perturbations, with consideration of the paleoenvironmental conditions. The rare earth element data show that the provenances of the Jehol Group in western Liaoning and northern Hebei were similar and derived mainly from the underlying andesite. Constrained by the radiometric age, the δ13Corg curve suggests that the Dadianzi Formation in northern Hebei is comparable to the three lacustrine layers of the Yixian Formation (ranging from the Jianshangou Bed to the Jingangshan Bed) in western Liaoning. These layers are highly correlated with the early Aptian marine sequence in Oceanic Anoxic Event 1a (OAE 1a), implying that a possible teleconnection (possibly related to a large igneous province) existed between oceanic and terrestrial realms. We also propose that the Xiguayuan Formation above the Dadianzi Formation in northern Hebei is equivalent to the Huanghuashan Breccia Bed at the top of the Yixian Formation in western Liaoning. Moreover, the δ13Corg and element geochemical data suggest that the carbon cycle perturbation and the paleolimnological environments were distinctly influenced by the effects of volcanic CO2 during the early Aptian.

New age constraints for the Middle Triassic archosaur Lotosaurus: Implications for basal archosaurian appearance and radiation in South China

Archosaurians were the dominant terrestrial tetrapods during the Mesozoic and became one of the most successful tetrapod clades on Earth following the end-Permian mass extinction. The lower Badong Formation in northwestern Hunan Province, South China hosts fossils representing the basal archosaurian Lotosaurus. The Badong Formation has been previously interpreted as Anisian-Ladinian (247–237 Ma) in age based on biostratigraphic correlations. This study presents new detrital zircon UPb age constraints for sandstones hosting Lotosaurus fossils in Sangzhi County of northwestern Hunan. Our data give a weighted mean age of 238.0 ± 1.4 Ma (Ladinian Stage) as the maximum depositional age for the fossil-bearing layer in the lower Badong Formation. This age is consistent with younger estimates from previous biostratigraphic studies. It is also more precise and stratigraphically constrained than previously published radiometric dating results for the units. This age estimate provides critical geochronologic constraint on the radiation of early archosaurians from China into other areas of Pangea beginning in the Early Triassic.

Revised geology, age, and vertebrate diversity of the dinosaur-bearing Griman Creek Formation (Cenomanian), Lightning Ridge, New South Wales, Australia

The mid-Cretaceous Griman Creek Formation (GCF), which crops out near the town of Lightning Ridge in the Surat Basin of north-central New South Wales, Australia, is noteworthy for its opalised vertebrate fauna. The fossil assemblage comprises remains of aspidorhynchid teleosts, lamniform chondrichthyans, dipnoans, chelid and possible meiolaniform turtles, leptocleidid-like and possible elasmosaurid plesiosaurians, anhanguerian pterosaurs, titanosauriform sauropods, megaraptoran theropods, ankylosaurians, several forms of non-iguanodontian and iguanodontian ornithopods, crocodylomorphs, enantiornithine birds, and stem and true monotremes, making it one of the most diverse mid-Cretaceous terrestrial vertebrate faunas in Australia. A detailed stratigraphic survey of twenty subterranean opal mines provides new information on the geology, age and palaeoenvironment of the main fossil-bearing beds. Vertebrate remains derive from the ‘Finch Clay facies’, laterally-extensive but discontinuous lenses of claystone that likely accumulated relatively rapidly in near-coastal but freshwater embayments (i.e. lagoonal conditions), and probably represent a single, roughly contemporaneous fauna. U-Pb age dating of detrital zircons extracted from a distinct layer of volcanogenic claystone immediately overlying one of the opalised fossil-bearing layers yields a maximum depositional age of 100.2–96.6 Ma. These new dates confirm an early to mid-Cenomanian age for the fauna, rather than Albian, as has been reported previously. The GCF at Lightning Ridge is therefore equivalent to the middle part of the Winton Formation (Queensland) and several million years older than the sauropod-dominated fauna at Winton.

Two medium-sized deinotheres (Proboscidea: Mammalia) from the Miocene rocks of the Eastern Carpathians Foreland (Romania)

The paper summarizes the medium-sized deinothere records from Romania, improving the palaeontological data of two less-known specimens from the Eastern Carpathians Foreland. The area is famous primarily by the large deinothere of Gaicena and Mânzaţi assigned to the “ Deinotherium gigantissimum” . Later, several fossils of Deinotherium were documented, but they remained generally unknown, and the morphological and biometrical data were not engaged in the further deinothere comparisons. The most important specimen is a fragmentary right hemimandible with well-fossilized m1-m2, housed in the “Ion Borcea” Natural History Museum of Bacau. The p3-p4 and m3 preserved only the roots; even there are not obvious reworking signs. Furthermore, a tibia sin. fragment were firstly added. The fossil remains were unearthed from the Late Bessarabian rocks (MN 9) near Dragesti (Bacau County). The second specimen represents an isolated M2 sin. of Deinotherium giganteum stored at the Museum of Paleontology “Alexandru Ioan Cuza” University of Iasi. It was collected from a microconglomerate bed (Early Bessarabian, ?MN 7-8–MN9) cropping out in the Pietraria Hill Quarry (Deleni, Iasi County). The age of fossil-bearing layers was accurately documented by several mollusc assemblages.

Isochron 26Al/10Be burial dating of the Lantian hominin site at Gongwangling in Northwestern China

The site of Gongwangling is among the most important early hominin sites in China due to the discovery of a partial Homo erectus cranium. Until recently the cranium has been widely accepted as ∼1.15 Ma (million years) in age based on magnetostratigraphy and loess/paleosol correlation. However, a revised magnetostratigraphic and pedostratigraphic study assigned a much older age of 1.63 Ma, making Gongwangling the second oldest hominin cranium-bearing site in Eurasia. Here we apply the isochron burial dating method as an independent check for the magnetostratigraphy. Samples from the top of a gravel bed ∼7 m below the fossil-bearing layer give an isochron burial age of 1.82 ± 0.12 Ma, in excellent agreement with the Olduvai subchron in the revised magnetostratigraphy, supporting the antiquity of the cranium.

A review on paleoenvironment suitability for hominid fossils and other early vertebrate faunas: a case from Pucangan and Kabuh Formations, Central and East Java, Indonesia

Abstract The northern part of the East Java Basin has become a focus of research by earth scientists, among others, because of the existence of hominid fossils and remains of other vertebrate taxa within the Quaternary sedimentary sequence. Fossil-bearing layers are found in the Kendeng Zone, mostly within the well-known Pucangan and Kabuh Formations, which are distributed from Central to East Java. However, not all formations contain vertebrate fossils as well as hominid elements. It is important to consider what factors may have influenced the concentration of vertebrate fossils in those formations. In this study, we describe sedimentary facies at three key field locations: Sangiran, Ngawi, and Mojokerto. Our study indicates that vertebrate remains and hominid fossils mainly accumulated in continental sediments associated with lacustrine and fluvial systems. In this regard, Sangiran and Ngawi B offer the greatest prospect for yielding hominid remains, owing to their unique paleoenvironmental and paleogeographical settings as a highland during the Early–Middle Pleistocene period. Certain parts of the Kabuh Formation in the Mojokerto region also hold high potential, especially those displaying evidence of continental deposition.

Mollusks of the Upper Jurassic (upper Oxfordian-lower Kimmeridgian) shallow marine Minas Viejas Formation, northeastern Mexico

We present the first systematic description of Late Jurassic (late Oxfordian-early Kimmeridgian) invertebrates from the shallow marine Minas Viejas Formation of northeastern Mexico. The unit was generally considered to be extremely poor in fossils, due to an overall evaporitic character. The collection described here includes three taxa of ammonites, 10 taxa of bivalves and five taxa of gastropods. The fossils were discovered near Galeana and other localities in southern Nuevo León and northeastern San Luis Potosí, in thin-bedded marly limestones intercalated between gypsum units. Due to complex internal deformation of the sediments, fossils used for this study cannot be assigned to precise layers of origin. However, the taxa identified suggest a Late Jurassic (late Oxfordian–early Kimmeridgian) age for these fossil-bearing layers and allow us, for the first time, to assign a biostratigraphic age to Upper Jurassic strata in the region underlying the La Caja and La Casita formations.

230Th/U chronology of a paleolithic site at Xinglong Cave in the three-Gorge region of south China

Xinglong Cave, containing four human teeth, numerous mammalian fossils, stone artifacts and a Stegodon tusk with intentional and seemingly grouped engravings, is one of the most significant archaic Homo sapiens sites in south China, located 95 km south of Fengjie County, in Chongqing. In an attempt to constrain the age of the human relics, calcitic flowstone deposits with a significant detrital component were dated by U–Th methods using a leachate scheme. Total sample digestion MC-ICPMS dating was used to assess the reliability of the leachate technique. Six calcite samples from horizons beneath and above the fossil-bearing layer were dated. We obtained ages of 130 ± 9.1, 124 ± 11, 135 ± 12 and 127 ± 11 ka for the flowstones above the fossil layer with a weighted mean of 128.9 ± 5.2 ka. Two flowstone samples gave MC-ICPMS dates between 128.3 ± 3.3 and 152.4 ± 25.3 ka with an assumed detrital component to correct for the initial 230Th, which are consistent with results obtained using the L/L regression data from layer U-4 within uncertainty. All errors herein quoted at the 2σ level. Ages determined for the flowstone underlying the fossil-bearing layer were 221 ± 29 to 189 ± 19 ka with a weighted mean age of 199 ± 16 ka. These results are stratigraphically consistent within error limits and show that the cave was occupied by Fengjie Man within the time range of ∼200 to ∼130 ka. These new U-series ages of flowstones in association with human teeth and an engraved stegodon tusk at the Xinglong Cave site provide valuable geochronologic information for the study of the origin of modern humans in East Asia and earliest human art.