Cretaceous coastal mountain building and potential impacts on climate change in East Asia
Data files
Aug 19, 2024 version files 1.10 MB
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Dataset_of_South_China_magmatic_rocks.xlsx
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README.md
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Supplementary_Table_S1.xlsx
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Supplementary_Table_S2.xlsx
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Supplementary_Table_S3.xlsx
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Supplementary_Table_S4.xlsx
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Oct 16, 2024 version files 1.21 MB
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Dataset_of_South_China_magmatic_rocks.xlsx
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README.md
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Supplementary_Table_S1.xlsx
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Supplementary_Table_S2.xlsx
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Supplementary_Table_S3.xlsx
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Supplementary_Table_S4.xlsx
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Supplementary_Table_S5.xlsx
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Oct 18, 2024 version files 1.21 MB
Abstract
Crustal thickness and elevation variations control mountain building and climate change at convergent margins. As an archetypal Andean-type convergent margin, eastern Asia preserves voluminous subduction-related magmas ideal for quantifying these processes and their impacts on climate. Here we use Sr/Y and Ce/Y proxies to show that the crust experienced alternating thickening and thinning episodes during the Late Mesozoic. We identify a noticeably thickened (50–55 km) crust associated with tectonic shortening at 120-105 Ma, corresponding to the emergence of a > 2500-m-high coastal mountain range. Using climate modeling, we demonstrate that the mountain uplift changed Asian atmospheric circulation and precipitation patterns, increased inland aridity (~ 15 %), and prompted the eastward desert expansion, contributing significantly to the arid zonal belt across mid- to low-latitude Asia. These findings, compatible with independent geological, geophysical, and climatic observations, have global implications for broadening our understanding of Earth-system interactions in the Cretaceous greenhouse world.
README
README
We have submitted (1) Rb/Sr and Sr/Y filtering criteria (Figure S1.pdf), (2) paleo-elevation estimates from the “in-situ” approach (Figure S2.pdf), (3) filtered geochemical data for intermediate-felsic rocks from South China used for plots of Sr/Y versus calculated crustal thickness (Supplementary Table S1.xlsx), (4) filtered geochemical data for mafic rocks from South China used for plots of Ce/Y versus calculated crustal thickness (Supplementary Table S2.xlsx), (5) available elevation and crustal thickness data from the Andes (Supplementary Table S3.xlsx), (6) geochemical data used for paleoelevation reconstruction of eastern South China in East Asia (Supplementary Table S4.xlsx), (7) compiled parameters used in the “in-situ” approach for the paleoelevation reconstruction (Supplementary Table S5.xlsx), and (8) dataset of South China magmatic rocks (Dataset of South China magmatic rocks.xlsx). (1)-(2) are uploaded as Supplemental information files, and (3)-(8) are uploaded as data files. Detailed descriptions are given below.
Descriptions
(1) Rb/Sr and Sr/Y filtering criteria
(A-C) Rb/Sr versus Sr/Y diagrams for Jurassic to Cretaceous intermediate to felsic magmatic rocks of South China. (D) Rb/Sr versus Sr/Y diagrams for magmatic rocks with 55-70 wt% SiO2 and 1-6 wt% MgO. Published data for Cretaceous magmatic rocks formed by sufficient crystal-melt separation are indicated to exclude highly fractionated and accumulated samples. After filtering, the data with 0.05≤Rb/Sr≤0.32 and 10≤Sr/Y≤40 were used to calculate the crustal thickness.
(2) Paleo-elevation estimates from the “in-situ” approach
(A) Crustal thickness map of South China based on the joint inversion of receiver function and gravity vertical gradient data (44). (B) Time series of paleoelevation (km) between 180 and 80 Ma, estimated from the “in-situ” approach. (C) Comparison of the calculation results. The two approaches yield broadly comparable elevation estimates; >95% of the elevation differences are within ± 500 m.
(3) Intermediate-felsic rocks from South China used for plots of Sr/Y versus calculated crustal thickness
Age(Ma): U-Pb ages, 40K-40Ar ages, and Rb-Sr isochron ages of samples (Ma)
Location: The locations from which the samples were obtained. Representative tectonic belts include the Coastal Terrane (CT), the Wuyishan (WYS), and the Gan-Hang belt (GH)
Lithology: The sample lithologies
SiO2-LOI: Major elements of the samples (wt%)
Ga-U: Trace elements of the samples (ppm)
Rb/Sr: The ratio of Rb/Sr
Sr/Y: The ratio of Sr/Y
Crustal thickness z: Calculated from the empirical formula: z = (7.25+Sr/Y)/0.9 (km)
1σ: Statistical uncertainties (km)
Age period of the fitting curve in Fig.3A: The piecewise polynomial regression analysis yielded the fitting curves in Fig. 3A, and the used data were divided into two groups with age periods at 161-125 and 116-95 Ma (Ma)
(4) Filtered geochemical data for mafic rocks from South China used for plots of Ce/Y versus calculated crustal thickness
Location: The locations from which the samples were obtained.
Lithology: The sample lithologies
Age(Ma): U-Pb ages, 40K-40Ar ages, and Rb-Sr isochron ages of samples (Ma)
SiO2-LOI: Major elements of the samples (wt%)
Sc-U: Trace elements of the samples (ppm)
Ce/Y: The ratio of Ce/Y
Crustal thickness z: Calculated from the empirical formula: z = 18.0505×Ln(Ce/Y)+21.5587 (km)
Age period of the fitting curve in Fig.3B: The piecewise polynomial regression analysis yielded the fitting curves in Fig. 3B, and the used data were divided into two groups with age periods at 140-105 and 104-80 Ma (Ma)
(5) Available elevation and crustal thickness data from the Andes
Longitude (S): Longitude of the samples
Latitude (W): Latitude of the samples
Location: The locations from which the samples were obtained
Crustal thickness: Based on published seismic reflection and refraction data in Andes (km)
Elevation: Present elevations of the samples (m)
(6) Geochemical data used for paleoelevation reconstruction of eastern South China in East Asia
Lithology: The sample lithologies
Location: The locations from which the samples were obtained. Representative tectonic belts include the Coastal Terrane (CT), the Wuyishan (WYS), and the Gan-Hang belt (GH)
Age: U-Pb ages, 40K-40Ar ages, and Rb-Sr isochron ages of samples (Ma)
SiO2-MgO: Major elements of the samples (wt%)
La-Y: Trace elements of the samples (ppm)
Rb/Sr: The ratio of Rb/Sr
Sr/Y: The ratio of Sr/Y
Ce/Y: The ratio of Ce/Y
Elevation: Calculated from the empirical formula: Elevation = [(1-0.9)×Crustal thickness-2.5]×1000 (m)
Elevation Uncertainty: Statistical uncertainties of Elevation (m)
Age period of the fitting curve in Fig.5A: The piecewise polynomial regression analysis yielded the fitting curves in Fig. 5A, and the used data were divided into two groups with age periods at 161-120 and 116-80 Ma (Ma)
Distance: The distance from the coastline (km)
Distance of the fitting curve in Fig.5B: The piecewise polynomial regression analysis yielded the fitting curves in Fig. 5B, and the used data were divided into three groups with different distances (0-80, 81-135, and 155-255 km) from the coastal line (km)
(7) Compiled parameters used in the “in-situ” approach for the paleoelevation reconstruction
Lithology: The sample lithologies
Location: The locations from which the samples were obtained. Representative tectonic belts include the Coastal Terrane (CT), the Wuyishan (WYS), and the Gan-Hang belt (GH)
Age: U-Pb ages, 40K-40Ar ages, and Rb-Sr isochron ages of samples (Ma)
SiO2-MgO: Major elements of the samples (wt%)
La-Y: Trace elements of the samples (ppm)
Rb/Sr: The ratio of Rb/Sr
Sr/Y: The ratio of Sr/Y
Ce/Y: The ratio of Ce/Y
Present-day crustal thickness: Based on published seismic reflection and refraction data in South China (km)
Present-day elevation: Present-day elevation of the samples derived from OpenStreetMap (m)
Paleo-crustal thickness: Calculated from the empirical formula: Paleo-crustal thickness=(7.25+Sr/Y)/0.9 (km); Paleo-crustal thickness = 18.0505 × Ln (Ce/Y)+21.5587 (km)
Paleo-elevation: Calculated from the empirical formula: Paleo-elevation = [(1-0.9)×Paleo-crustal thickness-2.5] × 1000 (m)
Paleo-elevation Uncertainty: Statistical uncertainties of Paleo-elevation (m)
Elevation difference: Calculated from the empirical formula: Elevation difference=Paleo-elevation - Elevation (m)
(8) Dataset of South China magmatic rocks
This dataset shows the whole-rock geochemical, geochronological, and isotopic analyses from 273 Jurassic-Cretaceous plutons and volcanoes from eastern South China. Please see Lines 105-109 in the Results section of the manuscript.
Name: The sample names
Age(Ma): U-Pb ages, 40K-40Ar ages, and Rb-Sr isochron ages of samples (Ma)
Location: The locations from which the samples were obtained. Representative tectonic belts include the Coastal Terrane (CT), the Wuyishan (WYS), and the Gan-Hang belt (GH)
Lithology: The sample lithologies
SiO2-LOI: Major elements of the samples (wt%)
Ga-U: Trace elements of the samples (ppm)
Version changes
12-aug-2024 All supplemental data files were re-checked and edited the data by adding missing values and replacing the empty cells with “N/A”.
14-oct-2024 Table S5 was added to list compiled parameters used in the “in-situ” approach for the paleoelevation reconstruction. Fig. S2 was added to show paleo-elevation estimates from the “in-situ” approach. Table S1 was updated by adding a new column (AU) to show the age period of the fitting curve in Fig. 3A. Table S2 was updated by adding a new column (AW) to show the age period of the fitting curve in Fig. 3B. Table S4 was updated by adding two new column (Q and S) to show the age periods of the fitting curves in Fig. 5A and Fig. 5B, respectively.
18-oct-2024 We updated the format of age periods in the README by starting with the large number, i.e., replacing “125-161 and 95-116 Ma” with “125-165 and 95-120 Ma” in the Descriptions item (3), replacing “105-140 and 80-104 Ma” with “105-140 and 80-104 Ma” in* the Descriptions item (4), and replacing “120-161 and 80-116 Ma” with “120-165 and 80-120 Ma” in the Descriptions item (6). The format of age periods in Table S1 (Column AU), Table S2 (Column AW), and Table S4 (Column Q) has also been updated accordingly.
Methods
Sr/Y and Ce/Y proxies Crustal thickness controls the Sr/Y variability of arc magmas by affecting the stabilization of mineral phases, which fractionates Sr (plagioclase) and Y (garnet) (14,21). Sr is compatible and partitions into plagioclase at low pressures (<10 kbar); at high pressures (>12 kbar), Sr becomes incompatible and enters the liquid phase, and plagioclase is less abundant (64). By contrast, Y is incompatible at low pressures and tends to partition into garnet and amphibole at high pressures (19). Consequently, Sr/Y is a qualitative indicator of the pressures (i.e., crustal depths) at which partial melting and crystal fractionation occur (22,23). Chapman et al. (21) suggest that the Sr/Y ratios of intermediate magmas vary with crustal thickness in the North American Cordillera, with larger Sr/Y ratios signifying greater pressures and, hence, crustal thicknesses. Based on large data sets of global arc lavas, Profeta et al. (19) propose Sr/Y and La/Yb empirical correlations that are feasible in monitoring the crustal thickness evolution of ancient convergent margins. In addition to intermediate magmas, crustal thickness controls the composition of arc basalts by modulating the degree of mantle melting (19). Mantle and Collins (20) quantitatively estimate the changes in the crustal thickness of the New Zealand orogen since 400 Ma using maximum Ce/Y ratios of arc basalts. The Sr/Y and Ce/Y empirical correlations have been corroborated and formulated by examining the calculated crustal thicknesses with the geophysically derived Moho depths (20,21,24).
Climate Modeling Here we use a fully coupled atmosphere-ocean general circulation model, i.e., the Community Earth System Model version 1.2.2 (CESM1.2.2) developed by the National Center for Atmospheric Research (NCAR). CESM1.2.2 includes dynamic atmosphere, ocean, land, sea ice, and runoff modules (Fig. S2a-b), which interact with each other through a coupler (65).
To explore the influence of the East Asian coastal mountains on the Asian climate in the mid-Cretaceous, two experiments, i.e., noCM (Fig. S2c) and CM (Fig. S2d), are conducted using the global topography compiled by Sewall et al. (66). In experiment noCM, the East Asian coastal mountain range does not exist (Fig. S2c). In comparison, a north-south oriented mountain at ~22-38 °N along the East Asian margin is included in experiment CM (Fig 6d). Accordingly, the differences in the experiment directly reveal the effects of the coastal mountains on the Asian climate. Given the zonally limited East Asian coastal mountains, we use a relatively high resolution of 0.9° × 1.25° for the atmosphere (CAM4.0) and land (CLM4.0) modules in the experiments. Notably, fully coupled running with a dynamic ocean at such a high resolution is forbidden due to limited computing resources. The two experiments are driven by fixed sea surface temperatures (SSTs) and sea ice with annual cycling, which are the monthly climatology of the third experiment (CPL). This experiment is a fully coupled run of the CESM1.2.2, in which the CAM4.0 and CLM4.0 are modeled at a resolution of 3.75° × 3.75°. The ocean (POP2) and sea ice (CICE4) modules employ a gx3v7 grid possessing 116 and 100 grid points in the meridional and zonal directions, respectively. The CAM4.0 and POP2 have 26 and 60 vertical levels, respectively. The runoff module runs at a resolution of 0.5° × 0.5°. The abovementioned methods are commonly used to model the topographical impacts on the regional climate (67-69). In this study, the experiment CPL runs for 3000 model years, which is long enough for the Earth's surface to reach a quasi-equilibrium state. The monthly climatology of the last 100-year SSTs and sea ice are used to force the experiments noCM and CM. These two uncoupled experiments run for 40 model years, and the data of the last 30 model years are analyzed here.
The other settings in the three experiments are concordant. The used solar constant is 1350.87 W/m2, 0.75% lower than the present value of ~1361 W/m2 (70). We set the CFC, pCO2, pCH4, and pN2O concentrations to 0, 1120 ppmv, 760 ppbv, and 270 ppbv, respectively. The influence of orbital forcing is not considered. We use the orbital parameters of 1990 CE in the modeling experiments. The default values of the CESM1.2.2 were used for all other atmospheric components (e.g., O3 and aerosols), all at preindustrial levels.