DOI: 10.5061/dryad.tdz08kq74
title: Cretaceous coastal mountain building and potential impacts on climate change in East Asia

description: 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 &gt;
 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.
description: <strong>Sr/Y and Ce/Y proxies  </strong>Crustal
 thickness controls the Sr/Y variability of arc magmas by affecting the
 stabilization of mineral phases, which fractionates Sr (plagioclase) and Y
 (garnet) (<em>14,21</em>). Sr is compatible and partitions
 into plagioclase at low pressures (&lt;10 kbar); at high pressures
 (&gt;12 kbar), Sr becomes incompatible and enters the liquid phase,
 and plagioclase is less abundant (<em>64</em>). By contrast, Y
 is incompatible at low pressures and tends to partition into garnet and
 amphibole at high pressures
 (<em>19</em>)<em>.</em> Consequently, Sr/Y is a
 qualitative indicator of the pressures (i.e., crustal depths) at which
 partial melting and crystal fractionation occur
 (<em>22,23</em>). Chapman et al. (<em>21</em>)
 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.
 (<em>19</em>)<sup> </sup>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
 (<em>19</em>). Mantle and Collins
 (<em>20</em>)<sup> </sup>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
 (<em>20,21,24</em>). <strong>Climate
 Modeling </strong>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 (<strong>Fig. S2a-b</strong>), which
 interact with each other through a coupler
 (<em>65</em>).   To explore the influence
 of the East Asian coastal mountains on the Asian climate in the
 mid-Cretaceous, two experiments, i.e., <em>noCM</em>
 (<strong>Fig. S2c</strong>) and <em>CM
 </em>(<strong>Fig. S2d</strong>), are conducted using
 the global topography compiled by Sewall et al. (<em>66</em>).
 In experiment <em>noCM</em>, the East Asian coastal mountain
 range does not exist (<strong>Fig. S2c</strong>). In
 comparison, a north-south oriented mountain at ~22-38 °N along the East
 Asian margin is included in experiment <em>CM</em>
 (<strong>Fig 6d</strong>). 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
 (<em>CPL</em>). 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
 (<em>67-69</em>). In this study, the experiment
 <em>CPL</em> 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 <em>noCM</em> and
 <em>CM</em>. 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/m<sup>2</sup>, 0.75% lower than the present value of ~1361
 W/m<sup>2 </sup>(<em>70</em>). We set the
 CFC,<em> p</em>CO<sub>2</sub>,
 <em>p</em>CH<sub>4,</sub> and
 <em>p</em>N<sub>2</sub>O 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., O<sub>3</sub> and
 aerosols), all at preindustrial levels.
description: **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; &gt;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.