A representative split of the heavy mineral concentrate (bulk-mounted) and handpicked grains were affixed in the same resin mount, enabling consistency for image analysis. In order to resolve this, continuing to ignore statistically significant sources of natural systematic bias will only result in formulation of systematically misleading geological hypotheses. Simply dating more crystals per sample is not the only answer. This is particularly critical as the number of publications including a component of detrital zircon provenance continues to grow, because this is inevitably driving the community toward a “big data” approach that will continue to increase its reliance on robust statistical treatments.

Therefore, it is necessary to evaluate the effectiveness of determining the age of deposition using zircon age data. Our results reveal zircons of late Cretaceous age, and the youngest peak ages are in good agreement with depositional ages inferred from radiolarian fossils. In addition, the youngest peak ages become younger as tectono-structurally downwards, and this tendency is clearer for the zircon ages than for the radiolarian ages. These results indicate that newly crystalized zircons were continuously supplied to the sediment by constant igneous activity during the late Cretaceous and that zircon ages provide remarkably useful information for determining the age of deposition in the Cretaceous Shimanto accretionary complex. We present data on the composition of metasedimentary rocks from the greenstone belt of the Onot terrane and results of U–Pb dating and Lu–Hf isotope study of detrital zircon from garnet–staurolite schists. The metasedimentary rocks of the Onot greenstone belt are dominated by garnet- and staurolite-bearing schists alternating with amphibolites in the upper part of the section.

It consists of Paleocene-Eocene marine sediments, overlain by Oligocene–Miocene and younger siliciclastic strata marking regional unconformity . In terms of the Himalayan classification , part of the internal metamorphosed zone, north of MCT (Laut Thrust/Batal Fault), marks the Greater/Higher Himalaya . The Lesser Himalayan zone is marked between the MBT and MCT (Laut Thrust/Batal Fault). The Hazara-Kashmir syntaxial region in Pakistan represents the foreland basin’s northern extreme, currently occupying the sub-Himalayan region .

Geological map of the Scott Coastal Plain in Western Australia. GB001 indicates the Governor Broome heavy mineral sand deposit used in this study. Main steps , modification processes and controlling factors of sediment evolution. Original figure 9 from Rehman et al. ; An example of ɛHf plot.

The timing and architecture for the accretion of the Bainaimiao arc to the North China Craton in southeast Altaids is a matter of intense debate. Here we use field- and stratigraphically-constrained detrital zircon U-Pb data of Silurian-Carboniferous marine sediments in Bayan Obo, Inner Mongolia, to constrain the accretionary history of the southeast Altaids. The geochronological results reveal that the maximum depositional ages of the first and second rock members of the Xibiehe, Chaganhabu, and Amushan formations are 423 ± 6, 416 ± 5, 412 ± 5, 391 ± 8, 322 ± 8, and 306 ± 4 Ma, respectively. Detrital zircon age spectra of the Xibiehe Formation, Chaganhabu Formation, and the first rock member of the Amushan Formation are characterized by unimodal age peaks (∼471–427 Ma), which resemble the magmatic events of the Bainaimiao arc. In contrast, the second rock member of the Amushan Formation yields Archean-Paleoproterozoic (∼2500 Ma) and Paleozoic (∼480–310 Ma) ages, indicating bidirectional provenance from the Bainaimiao arc and the North China Craton. This provenance change indicates that the collision between the Bainaimiao arc and the North China Craton occurred between ∼ 322–306 Ma.

Recent advances in the study of the Mesoproterozoic geochronology in the North China Craton

Here, p(t|MDA) refers to the probability of a particular age, t, characterizing an MDA. In the case of YGC2σ this would be governed by a normal distribution, but the probabilities of te are not necessarily normally distributed. The numerator in Equation 9 is just a mirror image of the cumulative density function of the MDA . The denominator in Equation 9 integrates over the age of the earth to ensure that the probabilities of all possible ages integrate to one.

Trace elements of these rocks indicate that the sequence was deposited in a passive continental margin environment and that the sedimentary detritus was derived from a Paleoproterozoic silicic-intermediate source, similar to other Paleo-Mesoproterozoic sedimentary sequences in the region. The Himalayas resulted from the India–Asia collision that occurred ≈56 Ma . Following the collision, a foreland basin was developed in the footwall of the MMT, which received detritus from the accreted Asian terranes, mainly the Kohistan–Ladakh arc . As a result of the continued subduction of the Indian plate in the north underneath, the Asian plate gave rise to Himalayan belt evolution by southward propagation of the fold-thrust belt. Determination of the depositional age of sedimentary rocks is essential for understanding tectonic processes, and microfossils have generally been used for this purpose.

All samples contain a cluster of grains with ZFT ages close to the depositional age and some of these grains have ZFT ages similar to their U–Pb age (Table 3, Fig.8). The Alpe de Taveyanne sample MRP006 contains 18 grains with single grain ZFT ages of 30–39 Ma; 14 of these grains have U–Pb ages of 30–34 Ma, but another 4 grains show U–Pb ages from 449 to 678 Ma. The Haute-Savoie sample 16GL02 contains 19 grains with ZFT ages from 30 to 37 Ma; among these, 8 grains have U–Pb ages between 32 and 34 Ma, 5 grains have U–Pb ages from 314 to 590 Ma and the remaining ones have discordant U–Pb ages. Similarly, 16GL17 contains 10 grains with ZFT ages from 30 to 40 Ma; 7 have U–Pb ages between 32 and 34 Ma and 3 other grains have U–Pb ages between 305 and 462 Ma. Those grains with young and identical ZFT and U–Pb ages are identified as volcanic zircons; those with old U–Pb ages, however, represent basement zircons, coming from exhumed units in the hinterland.

Detrital zircon record and tectonic setting

Source rocks and detritus are transported by gravity, water, wind or glacial movement. The transportation process breaks rocks into smaller particles by physical abrasion, from big boulder size into sand or even clay size. At the same time minerals within the sediment can also be changed chemically. Only minerals that are more resistant to chemical weathering can survive (e.g. ultrastable minerals zircon, tourmaline and rutile).

Efforts to ascertain the original purpose of the megaliths themselves should be directed at undisturbed sites or newly recorded sites and those with concealed contents or buried megalithic jars, instances of which are known. The U-Pb dating undertaken on the zircons from a jar from Site 1 matches the dates obtained from rock and an unfinished jar at Site 21 , the presumed quarry. While this does not preclude that sandstone of similar age exists in other areas accessible to the site, it is the only known quarry site in close proximity to have been identified to date. Extensive geological mapping of the region is hindered by the lack of high-resolution maps and foot survey is not possible in many areas around the site due to UXO. How the jars, some estimated to weigh more than 30 tonnes, were transported from the quarry to their final position is unknown, though is likely to have required a substantial workforce.

Igneous rock petrogenesis

The results presented in this study cast doubt on the often assumed randomness of handpicked age distributions used for inter-sample comparison. Although handpicking may be a preferred approach when targeting specific populations (e.g. to constrain the maximum depositional age) or to capture every age mode of the detrital record, studies interested in representative age distributions should whenever possible avoid handpicking. Individual studies and those referring to them, as well as studies making use of the global detrital record, will be positively impacted in terms of statistical robustness by omitting a potential source of bias.

For finer grained sediments, as they always lose paragenetic information, only a limited range of analytical methods can be used. Depend on properties of Sm–Nd radioactive isotope system can provide age estimation of sedimentary source rocks. 143Nd is produced by α decay of 147Sm and has a half life of 1.06×1011 years.

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These Himalayan tectonic terranes consisted of particular detrital zircon age signatures. These terranes uplifted with the development of new faults in response to fold-thrust belt propagation. Particularly, the U-Pb ages compared with the Th/U ratio indicates the derivation from the igneous and metamorphic sources of the Proterozoic and Cambro-Ordovician rocks.

Velikoslavinskii, S.D.; Kotov, A.B.; Sal’nikova, E.B.; Larin, A.M.; Sorokin, A.A.; Sorokin, A.P.; Kovach, V.P.; Tolmacheva, E.V.; Gorokhovskii, B.M. Age of Ilikan Sequence from the Stanovoi complex of the Dzhugdzhur–Stanovoi superterrane, Central-Asian Fold belt. Kotov, A.B.; Vladykin, N.V.; Larin, A.M.; Gladkochub, D.P.; Salnikova, E.B.; Sklyarov, E.V.; Tolmacheva, E.V.; Donskaya, T.V.; Velikoslavinsky, S.D.; Yakovleva, S.Z. New data on the age of ore formation in the unique Katugin rare-metal deposit . Larin, A.M.; Sal’nikova, E.B.; Kotov, A.B.; Makar’ev, L.B.; Yakovleva, S.Z.; Kovach, V.P. Early Proterozoic gotoplaydate com syn-and postcollision granites in the northern part of the Baikal Fold Area. Mattinson, J.M. Analysis of the relative decay constants of 235U and 238U by multi-step CA-TIMS measurements of closed system natural zircon samples. Hara, H.; Kurihara, T.; Tsukada, K.; Kon, Y.; Uchino, T.; Suzuki, T.; Takeuchi, M.; Nakane, Y.; Nuramkhaan, M.; Chuluun, M. Provenance and origins of a Late Paleozoic accretionary complex within the Khangai–Khentei belt in the Central Asian Orogenic Belt, central Mongolia. Wang, T.; Tong, Y.; Zhang, L.; Li, S.; Huang, H.; Zhang, J.; Guo, L.; Yang, Q.; Hong, D.; Donskaya, T.; et al.