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The Pearl River is one of the largest rivers entering the South China Sea, yet its initiation time remains debated, a topic we address using Pb isotopes in detrital K‐feldspar. Based on these Pb data, Eocene and Early Oligocene sandstones from the northern South China Sea are interpreted to have been supplied with sediment by proximal rivers draining the Cathaysia Block. In contrast, the Late Oligocene and Miocene sandstones are mainly derived from the western Pearl tributaries (e.g., Hongshui River), suggesting that the Pearl River had formed by the Late Oligocene. Detrital zircon data from the Beibuwan Basin previously suggested that the western tributaries flowed into this basin before being captured by the paleo‐Pearl River. These lines of evidence suggest that progressive headward erosion of the eastern Pearl River and late Oligocene integration of this large fluvial system can be linked to contemporaneous sea‐floor spreading of the South China Sea. Plain Language Summary: The Pearl River is one of the largest rivers flowing into the South China Sea. However, when this river achieved its present drainage character remains debated. Here we report a comprehensive investigation of sand/sandstone provenance of the Pearl River as well as the Pearl River Mouth Basin (PRMB) using Pb isotopes measured in detrital K‐feldspar. Our results suggest that Eocene and Early Oligocene sandstones were mainly fed by proximal rivers within the Cathaysia Block, while the Late Oligocene samples are enriched in K‐feldspar grains from the Hongshui River, suggesting that the Pearl River had achieved its present character by the Late Oligocene. Early Oligocene deposits in the Beibuwan Basin share an indistinguishable detrital zircon provenance signal to that of the western tributaries of the Pearl River, indicating that the western tributaries likely flowed into the Beibuwan Basin before being captured by the paleo‐Pearl River. Taken together, this evidence suggest that progressive headward erosion of the eastern Pearl River triggered by the subsidence of PRMB and sea‐floor spreading of the South China Sea played an important role in the late Oligocene integration of this large fluvial system. Key Points: Sedimentary provenance of the Pearl River and Pearl River Mouth Basin constrained using detrital K‐feldspar Pb isotopesPb isotopic data indicate that the Pearl River achieved its present character by the Late OligoceneThe opening of the South China Sea played an important role in the drainage reorganization of the Pearl River [ABSTRACT FROM AUTHOR]

The sedimentary archive of the Jianchuan Basin provides a critical constraint on the formation of the "First Bend", a major geomorphological feature of the Yangtze River, involving an abrupt 150° change in flow direction. Despite extensive detrital zircon provenance studies, no consensus has been reached on the timing of this event. Prior to the formation of the First Bend, the Yangtze is thought to have flowed southwards through the Jinchuan Basin, entering the South China Sea via the Red River. In this study, we constrain the timing of the First Bend using detrital K-feldspar Pb isotopic and detrital zircon U-Pb age datasets from Jianchuan Basin sandstones. Provenance data from late Eocene detrital zircon and K-feldspar populations concur in suggesting that they were fed by the southward flowing paleo-upper Yangtze River. Distinct K-Feldspar Pb isotopic data indicate that the overlying later Eocene and Pliocene deposits were fed by local Eocene syenites, granites and tuffs. Stratigraphic constraints on this change in provenance indicate that the southward flowing paleo-Yangtze River was cut off in the late Eocene at or before ∼37 Ma, thereby dating the formation of the First Bend. In contrast, detrital zircon U-Pb geochronology from the youngest units within the Jianchuan Basin is similar to those of the older sandstones and upper Yangtze River sands. This evidence indicates that the majority of zircons deposited in the upper part of the Jianchuan Basin were recycled from older sedimentary rocks. In our view, much of the disagreement relating to the formation time of the First Bend can be attributed to the failure to recognize sedimentary recycling. This study highlights the need to consider the possible presence of recycled detrital zircons when investigating paleo-drainage systems. [ABSTRACT FROM AUTHOR]

The origin and development of the major rivers in the eastern Tibetan Plateau have been a special focus of research because of the close links recognized between river formation, tectonic uplift, and climate change. In this article, we review a number of sedimentary provenance investigations aiming to constrain the drainage evolution of the main rivers draining eastern Tibet, including the Mekong, Red, Pearl, Yangtze, and Yellow rivers. The Mekong River was formed no later than ~17 Ma, likely triggered by a period of enhanced East Asian summer monsoon precipitation during the middle Miocene. A single large paleo-Red River draining the southeastern Tibetan Plateau into the Song Hong - Yinggehai Basin had been proposed to explain the unusual drainage pattern. However, this is not compatible with the distinctive provenance signals in the southeastern Tibetan river sands compared with the Song Hong - Yinggehai Basin, indicating that there has been no large-scale paleo-Red River since the late Eocene. The Pearl River has formed during the late Oligocene, as there was a sharp provenance change in the Pearl River Mouth Basin. Moreover, rivers draining southeast coastal China (e.g., Min River) migrated westward at the same time. These clues highlight that paleo-rivers in southeastern China started to migrate inland during the Late Oligocene. In contrast, the formation timing of the Yangtze River is still under intensively debated, ranging from late Cretaceous to Holocene, mainly due to the complex evolution history of this trans-continental river. The formation of the First Bend of the Yangtze River likely happened during the late Eocene, resulting from changes in the regional topographic gradient triggered by local magmatic activity and/or movement of the Ailao Shan-Red River Fault. Onshore and offshore provenance evidence indicate that incision of the Three Gorges happened no later than the late Miocene. Formation of the Square Bend of the Yellow River occurred prior to the late Pliocene, while incision of the Sanmen Gorge, a key capture point connecting the upper-middle and lower Yellow River likely occurred in the early Pleistocene (~1.2 Ma). Multi-provenance proxies on well-dated and continuous sedimentary records can provide objective information in terms of the origin and evolution of the major rivers flowing from eastern Tibet. Although the evolution of these rivers remains debatable, a comparison among the river evolution, climatic and tectonic events suggests that Eocene local and isolated drainage patterns is likely related to the dry climate condition in the East Asia. Oligocene and late Miocene inlandward expansion and integration of rivers coincides with both the formation of the East Asian Monsoon and the timing of major tectonic events, such as the growth of the Tibetan Plateau and the rifting and opening of the eastern Asian marginal basins, highlighting the importance of climate and tectonics in controlling the evolution of major rivers. [ABSTRACT FROM AUTHOR]

Cenozoic passive margin sediments in Taiwan provide an important natural archive to reconstruct drainage reorganization in eastern China. In this study, we used Pb isotope compositions of detrital K-feldspar to investigate the sedimentary provenance of Cenozoic strata in Taiwan and to constrain fluvial system evolution in eastern China. Eocene to lower Oligocene sandstones in Taiwan are characterized by radiogenic K-feldspar grains (206Pb/204Pb>18.4), indicating that the eastern Cathaysia Block served as the dominant sediment contributor. In contrast, a late Oligocene sample has a Pb isotopic character indistinguishable from that of the Gan River, a major tributary of the Yangtze River. This provenance change is interpreted as the result of headward (westward) migration of the paleo-Min River to the Wuyishan (Wuyi Mountains) during the late Oligocene. Miocene deposits are enriched in relatively unradiogenic K-feldspar (206Pb/204Pb<17.0) which can be reliably traced back to the Dabie and Sulu orogenic belts. Since the early Miocene, the paleo-Yangtze River, mainly draining the Yangtze Craton and the Dabie orogenic belt, delivered a large volume of detritus to the East China Sea Shelf Basin and also to the proto-Taiwan region. [ABSTRACT FROM AUTHOR]

The timing of formation of the Three Gorges, a critical capture point on the Yangtze River, has been debated for more than a century. In this paper, we review the existing evidence and apply two sedimentary provenance proxies (Pb isotopic compositions of detrital K-feldspar and detrital zircon U Pb ages) to date its incision based on samples from the early Cretaceous to Quaternary western Jianghan Basin and from the Neogene Yangtze Gravel, both located downstream of the Three Gorges. We show that from the early Cretaceous to the late Eocene, the western Jianghan Basin was mainly fed by the proximal sources, including the Qinling orogen and the Huangling dome. Similarly, from the latest Oligocene to the Miocene, local paleo-rivers supplied the Yangtze Gravel, mainly from the nearby Tongbai-Dabieshan. By the late Pliocene, the Jianghan Basin was fed by a river delivering sands with a Pb isotopic character indistinguishable from that of the modern Yangtze River. These provenance indicators suggest that the Three Gorges was cut through after the late Miocene (~10 Ma) but prior to the late Pliocene (~3.4 Ma). Cretaceous-Cenozoic deposits from the Jianghan Basin and the Yangtze Gravel have a detrital zircon U Pb geochronology signature indistinguishable from that of the modern Yangtze River. It is inferred from this that the detrital zircon provenance signal has effectively been homogenized by complex transportation/recycling processes in the Yangtze Craton. [ABSTRACT FROM AUTHOR]

• We apply in-situ Rb-Sr, Ar-Ar, and Pb-isotope analysis to ice-rafted K-feldspar. • Detrital Rb-Sr ages agree well with known onshore bedrock ages. • Our data support mid-Miocene formation of major Antarctic Ice-sheet embayments. The latest generation of Antarctic paleo-ice sheet models, incorporating bedrock paleo-topography, reconstruct the development of substantial ice-sheet embayments during the Mid-Miocene Climate Optimum, a warm period between ∼17–15 Ma ago. Here, we test these models using ice-rafted debris (IRD) recovered from the central Weddell Sea (Ocean Drilling Program Site 113–694). These IRD are entrained by the ice-sheet expanding into the embayment during the cooling associated with the subsequent Mid-Miocene Climate Transition and ultimately delivered to the deep marine sink by iceberg armadas during higher-frequency instability events. Due to the near-absence of heavy minerals in these volumetrically small samples, we utilise the novel in-situ K-feldspar 87Rb/87Sr provenance technique by laser-ablation inductively coupled mass spectrometer equipped with a mass-filtered reaction cell. We combine these single-grain ages with in-situ Pb-isotope analysis, as well as 40Ar/39Ar dating of a subset of grains. Results identify the Antarctic Peninsula and southern Dronning Maud Land as key sediment sources, including grains sourced from within the Recovery subglacial basin. These findings support ice sheet instability consistent with reconstructions of major ice sheet embayments formed by climatic conditions analogous to those predicted by modern anthropogenic warming trajectories. Additionally, in-situ 87Rb/87Sr and Pb-isotope analysis of detrital K-feldspar provide a high-throughput alternative to conventional single grain U-Pb or 40Ar/39Ar analysis, especially in small samples where the heavy mineral fraction is limited or absent. [ABSTRACT FROM AUTHOR]

Foreland basin sediments are key archives of orogenic development, preserving a record of past tectonic and climatic processes. This record can be read by employing single-grain detrital geo- and thermochronometers as detrital provenance indicators. Detrital provenance plays a crucial role in Earth Science as a research multiplier: c. 3,800 published articles with these keywords have been cited c. 92,000 times (c. 59,000 times in the last five years; Clarivate Analytics Web of Science), the bulk of which (c. 2,800/3,800) employed detrital geo- or thermochronometry. Fundamental to this approach is the assumption that tectonically- or climatically-driven changes in the location or tempo of erosion will expose thermochronologically distinctive sediment sources within the orogen. The chosen mineral thermochronometer(s) must therefore possess three key characteristics: (1) an appropriate thermal and chemical sensitivity, which will yield reset ages in a limited but non-zero number of source units; (2) occur in a wide range of source rock types, to prevent lithological bias; and (3) be sufficiently mechanically and chemically stable at the Earth's surface to allow widespread preservation in sedimentary rocks. However, a large majority of published detrital provenance studies utilising geo- or thermochronometry (c. 2,200/2,800) employ the zircon U-Pb technique. This phase is highly favourable analytically, incorporating high U and Th concentrations and often trivial common-Pb. However, zircon is often subject to bias, especially with regard to source lithology, and thermal and chemical sensitivity. In orogens which lack widespread felsic magmatism the zircon U-Pb age distribution is typically dominated by ages recording older geological events, inherited by recycling through sedimentary and metamorphic rocks incorporated in the orogenic wedge. In many cases, therefore, the use of multiple thermochronometers, present in a wider range of source lithologies and exhibiting a more varied thermal and chemical sensitivity is required. Here, we present case studies from the Alpine, Himalayan, and Caledonian orogens, exploring the possibilities and limitations of detrital U-Pb and elemental abundance analysis of apatite, rutile, and titanite, which we contrast with zircon U-Pb data. [ABSTRACT FROM AUTHOR]