Phosphorus (P) is an essential element for the evolution of life and circulates between different layers of the Earth through carriers such as igneous and sedimentary rocks. Geochemical analyses show ...that the variation of P concentration in igneous rocks, especially volcanics, affected the P fluctuation in coeval marginal sedimentary rocks deposited in shallow marine environments over most of geological time. The continuous increase of P concentration in volcanics resulted from decreased melting degrees due to Earth's cooling. Supercontinent assembly and massive subduction within the supercontinent cycle could result in spikes of volcanic P. Two-stage variation of volcanic P and the distinct proportion of juvenile crust provided evidence for global plate tectonics beginning at ~2.1 Ga. Oxygenation events on the Earth's surface increased marginal sedimentary P and thus decreased complementary distal sedimentary P deposited in abyssal marine environments that could enter the mantle by subduction. They had a lag effect on the decreasing P concentration of ensuing volcanics undergoing weathering and riverine transport to marine ecosystems, forming negative feedback. Therefore, the global tectonics and oxygenation events drove the Earth-scale P cycle, profoundly affecting the evolution of different layers of the Earth, especially the biosphere.
•P cycle links the deep Earth and biosphere by magmatism and plate subduction.•Earth's cooling and supercontinent cycles affect volcanic P variation.•Abrupt volcanic P change may suggest the initiation of global plate tectonics at ~2.1 Ga.•Oxygenation events contribute to the P fluctuations in marginal and distal sediments.•Negative feedback exists between volcanic and marginal sedimentary P during oxygenation events.
Cratons are the most mature parts of the continents on Earth and can remain stable for billions of years. Cratonic keels may be destroyed, for which a prime example is the eastern North China craton ...(NCC), which was removed during the Mesozoic. However, the critical stable state of the keel and the destroying mechanism of the rigid and buoyant cratonic roots remain enigmatic. Here, rhenium-osmium and neodymium isotope datasets from the eastern NCC open up a possible approach to reveal its evolution prior to the destruction. Two Re (rhenium) -depletion model age peaks of the peridotite xenoliths entrained by Phanerozoic basalts reconcile the ages of the large igneous provinces (LIPs) of Yanliao (ca. 1.3 Ga) and Xuhuai (ca. 0.92 Ga), respectively. This indicates that the mantle lithosphere of the eastern NCC has undergone metasomatism and growth during the emplacement of the two LIPs. The Proterozoic LIPs probably produced buoyant mantle residues that were then captured beneath thinned lithosphere regions. Such igneous processes occur at a depth of ~100 km and may induce the formation of weak zones (e.g. palaeo-mid-lithosphere discontinuity) partially within the rigid mantle lithosphere. The palaeo-weak zones might be rheologically unstable structures and probably reduced the stability of the craton, presenting as foci for potential later keel destruction. This provides evidence that LIP event may be another key factor for the intra-cratonic mantle lithosphere destruction.
Phosphorus (P) is one of the most critical limiting nutrients for biological evolution, and volcanic rocks are a crucial source of available P for terrestrial ecosystems. Volcanic-sedimentary records ...indicate that massive volcanism on the North China Craton in the late Mesozoic supported the evolution of terrestrial biotas. The variation of P content in the Mesozoic mafic volcanics mainly results from melt-garnet reactions during lithospheric thinning. The high P contents in most mafic volcanics worldwide could be related to the contents of olivine and clinopyroxene. In contrast, P variation in felsic volcanics could depend on apatite saturation. In the Phanerozoic volcanics, P content increases with the decrease of rock ages, resulting from the Earth's cooling. The contents of P and SiO2 in these Phanerozoic volcanics have similar variation trends. However, this is not the case for intrusive rocks, which could have experienced more complex and protracted magmatism. Therefore, deep processes and associated magmatism control the variation of P in volcanics, ultimately reflected in the evolution of surface ecosystems.
•Late Mesozoic volcanic P supply supported the evolution of terrestrial biotas.•Melt-garnet reactions affected mafic volcanic P variation with lithospheric thinning.•Olivine and clinopyroxene contributed to P variation in mafic volcanic rocks.•Apatite saturation resulted in P variation in felsic volcanic rocks.•The P content in the Phanerozoic volcanic rocks increased with Earth's cooling.
The Jehol and Yanliao biotas of northern China, two world‐class Lagerstätten with abundant biomass and biodiversity, provide critical clues to Mesozoic terrestrial ecosystems. Their evolution is a ...response to the destruction of the North China craton. However, the impetus for the rapid bloom of the biotas remains a mystery. Mesozoic large‐scale volcanic‐sedimentary strata in northern China are rich in terrestrial organisms. Statistical analyses show that volcanic nutrient element delivery, biomass, and biodiversity in these stratigraphic sequences increase synchronously, while harmful elements have the opposite change with them. These observations reveal the coevolutionary relationship between volcanism and terrestrial biotas. The increased nutrient element supply and inhibited harmful element delivery to terrestrial ecosystems from the voluminous volcanic products, produced under the geodynamic regime of paleo‐Pacific subduction and cratonic destruction, could create a conducive environment for the biodiversity and high prosperity of Mesozoic terrestrial biotas.
Plain Language Summary
The weathering of volcanic products can quickly provide material supply for ecosystems, including nutrient and harmful elements. The availability of these elements in volcanic‐sedimentary sequences can provide key evidence for the intrinsic relations between volcanism and terrestrial biological evolution. Through statistically‐based big data analyses, we determine the changes in nutrient/harmful element delivery, biomass, and vertebrate and entomic diversity of the Mesozoic fossil‐bearing volcanic‐sedimentary strata in northern China. Excluding the interference of pyroclastic flows on the fossil records, the results reveal the significant contributions of elevated volcanic nutrient supply to the flourishing of the Jehol and Yanliao biotas. Meanwhile, the inhibited release of harmful elements has limited impacts on the biotas. This study opens a new path for multidisciplinary investigations to explore the feedback relationship among regional tectonics, volcanism, and terrestrial biotas.
Key Points
Mesozoic terrestrial biotas in northern China coevolved with volcanism during the paleo‐Pacific subduction and cratonic destruction
The increasing supply of volcanic nutrients promoted the flourishing of the Jehol and Yanliao biotas
Inhibited volcanic toxic delivery facilitated the rapid bloom of the terrestrial biotas
Zircon U–Pb ages, geochemical and Sr–Nd–Pb isotopic data are presented for the late Paleozoic volcanic rocks from Xilinhot in central Inner Mongolia, North China. The Xilinhot volcanic rocks show a ...bimodal distribution in composition, with dominant rhyolite and dacite, subordinate basalt and local andesite. New SHRIMP and LA-ICPMS zircon U–Pb isotopic data constrain their magmatic emplacement at ca. 280 Ma. The mafic samples are characterized by high abundances in Th, U and Pb, slightly enriched LREE patterns and low HFS/LREE ratios. These features, together with their OIB-like isotopic signature (
87Sr/
86Sr
(
t)
≈
0.704 to 0.705,
ε
Nd(
t)
≈
+
6.87 to +
7.90, (
206Pb/
204Pb)
i
≈
18.30 to 19.06), indicate that they were likely derived from high percentage partial melting of a subduction-related metasomatized asthenospheric mantle in the spinel facies field at depths shallower than 60–70 km. The felsic rocks show an A-type affinity, with typical enrichment in alkalis, Ga, Zr, Nb, Ce, Y, and depletion in Sr, P, Eu, and Ti, and fractionated REE patterns with very strong negative Eu anomalies. Combined with their moderately positive
ε
Nd(
t) values (+
1.85–+
3.60), they are inferred to be generated by the mixing between partial melts of a newly underplated lower crustal source and an ancient felsic crustal source. The typical magma progression starting with asthenospheric melts then proceeding to lithospheric melts indicates that Early Permian magmatism in central Inner Mongolia occurred in an extensional setting, most probably related to the post-collisional delamination. Therefore, the occurrence of this unique bimodal magmatism not only demonstrates that the Solonker zone experienced final amalgamation of arc-related terranes by the late-Carboniferous, but also indicates that significant vertical continental growth of crustal continuum through repeated magmatic underplating occurred in the continental interior during post-collisional extension.
The Middle‒Late Mesozoic massive volcanism formed a considerable thickness of volcanic‐sedimentary strata in western Liaoning, northern China. Concomitantly, it elevated phosphorus (P) availability ...for the rapid bloom of the terrestrial Yanliao and Jehol biotas, which developed highly abundant biodiversity and biomass. Hence, systematic tectonic and geochemical analyses of these volcanic‐sedimentary sequences with a significant P fluctuation would advance our understanding of the coevolutionary relationship between terrestrial biotas and regional tectonics. Here, we show that the secular variation of P availability in the Mesozoic volcanic rocks were the immediate results of the changes in volcanic intensity and lithospheric thickness controlled by the geological background of the cratonic destruction resulting from the paleo‐Pacific plate subduction. This study reveals the constraint effect of regional tectonics on the evolution of terrestrial ecosystems through the volcanism and P cycle.
Plain Language Summary
The phosphorus (P) is necessary for biotas and mainly comes from volcanics in areas dominated by volcanism closely related to deep‐Earth processes. Thus, the origin of P changes in volcanics can provide key evidence for the intrinsic relations between deep processes and biota evolution. Here, we present tectonic and geochemical analyses for the Mesozoic fossil‐bearing volcanic‐sedimentary strata in northern China. The westward subduction of the paleo‐Pacific plate triggered the crustal thickening and subsequent lithospheric thinning of the East Asia continent. These dynamic processes controlled the volcanic intensity and P variation, resulting in remarkable changes in P availability that led to the rise and fall of terrestrial biotas. Hence, P variations in volcanic sequences reveal the linkage between regional tectonics and biota evolution. This study represents an effort to explore how tectonic processes constrained terrestrial biotas involving multidisciplinary methods.
Key Points
The paleo‐Pacific subduction triggered the cratonic destruction and thus controlled the intensity of volcanism in the Middle‒Late Mesozoic
The change of lithospheric thickness triggered by the paleo‐Pacific subduction caused the variation of P content in the volcanics
Regional tectonics could impact the evolution of terrestrial ecosystems through the volcanism and nutrient P cycle
Variations of continental lithosphere thickness through time is crucial for understanding destruction and regrowth processes in the cratonic region. The North China craton (NCC) is well-known for its ...various degrees of destruction since ∼200 Ma: the eastern portion was significantly thinned to 60–80 km, while the western part remained thick (>160 km). Nevertheless, the variation of lithospheric thickness in the central NCC remains elusive. Here we use thermobarometers of both liquids and minerals (olivine and clinopyroxene) to estimate the equilibrium depths of Hebi alkaline basalts (6.4 Ma) and evaluate the thickness of lithosphere beneath the volcanic fields (with eruption ages of 30–0.1 Ma) of the central NCC. Results show that the lithospheric thickness is ∼90–100 km, thinner than the current estimated by seismic observations (90–130 km). This variation indicates that the central NCC's lithosphere underwent Mesozoic thinning and Cenozoic accretion. Olivine-dominated cumulates in melt pooling close beneath the lithosphere-asthenosphere boundary and the buoyant mantle residues might be key components that have contributed to the re-healing of the thinned lithosphere.
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•Variation of lithospheric thickness beneath the central NCC is evaluated.•The central NCC's lithosphere underwent Cenozoic accretion.•Olivine-dominated cumulates are key components to the cratonic re-healing.
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