# Paleo-pCO2 Database: Early Miocene CO2 reconstructions of Inner Mongolia
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#               World Data Service for Paleoclimatology, Boulder
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#                      NOAA Paleoclimatology Program
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# Description/Documentation lines begin with '#' followed by a space
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# NOAA_Landing_Page: https://www.ncei.noaa.gov/access/paleo-search/study/36777
#   Landing_Page_Description: NOAA Landing Page of this file's parent study, which includes all study metadata.
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# Study_Level_JSON_Metadata: https://www.ncei.noaa.gov/pub/data/metadata/published/paleo/json/noaa-forcing-36777.json
#   Study_Level_JSON_Description: JSON metadata of this data file's parent study, which includes all study metadata.
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# Data_Type: Climate Forcing
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# Dataset_DOI:
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# Science_Keywords: carbon cycle, Atmospheric Gas Reconstruction
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# Resource_Links
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# Data_Download_Resource: https://www.ncei.noaa.gov/pub/data/paleo/climate_forcing/trace_gases/Paleo-pCO2/stomata_si_liang_2022b.txt
#   Data_Download_Description: NOAA Template File; CO2 Reconstruction Data
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# Contribution_Date
#   Date: 2022-08-30
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# File_Last_Modified_Date
#   Date: 2022-09-01
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# Title
#   Study_Name: Paleo-pCO2 Database: Early Miocene CO2 reconstructions of Inner Mongolia
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# Investigators
#   Investigators: Liang, Jia-qi; Leng, Qin; Xiao, Liang; Hofig, Daianne; Royer, Dana; Zhang, Yi.; Yang, Hong
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# Description_Notes_and_Keywords
#   Description: paleo-CO2 reconstructions from leaf gas exchange proxy
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# Publication
#   Authors: Liang, J., Leng, Q., Xiao, L., Höfig, D. F., Royer, D. L., Zhang, Y. G., and Yang, H.
#   Published_Date_or_Year: 2022
#   Published_Title: Early Miocene redwood fossils from Inner Mongolia: CO2 reconstructions and paleoclimate effects of a low Mongolian plateau
#   Journal_Name: Review of Palaeobotany and Palynology
#   Volume: 305
#   Edition: 
#   Issue: 
#   Pages: 10473
#   Report_Number: 
#   DOI: 10.1016/j.revpalbo.2022.104743
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#   Full_Citation: 
#   Abstract: The early Miocene (~16–23 Ma) marks a critical transition in the Earth climate history from an Oligocene
(~23–34 Ma) cooling trend towards the well-documented warm middle Miocene Climate Optimum at ~
15 Ma. In eastern Asia, this transition links changes of key topographic features, such as the Tibetan plateau
and the Mongolian plateau, and their impact on the reorganization of climate systems, such as the Eastern
Asian summermonsoon. Yet the dynamics of the interplay among these factors remain poorly understood, precluding
our understanding of future climate changes. Global temperatures during the early Miocene were
warmer than the present day by 3–4 °C, which are seemingly incompatible with both the low (<300 ppm)
and high (>800 ppm) ends of presently available reconstructions of atmospheric carbon dioxide (CO2). Here
we report a rare co-occurrence of two redwoods, Metasequoia and Sequoia, from sediments of the early Miocene
Hannuoba Formation in Zhuozi County in China’s Inner Mongolia at the southeastern margin of the current
Mongolian plateau. The Zhuozi Metasequoia fossils possess uneven type cuticles, which dominate its living population
but have rarely been reported throughout the abundant fossil record of this genus. By applying wellconstrained
Franksmodel parameters obtained fromthese redwood fossils using a cleared leaf epidermis method,
we estimated the earlyMiocene CO2 level at ~400 ppm, putting it at the lower end of the model requirement for
sustaining a relatively warm global temperature during this period. Our Franks model estimates are ~100 ppm
higher than that obtained using stomatal index method based on Metasequoia material, further confirming a
systematic underestimation of ancient CO2 using the Metasequoia stomatal index method reported in previous
analyses. We recommend a re-examination of previous CO2 reconstructions solely based upon Metasequoia’s
inverse relationship between stomatal index and CO2 concentrations. Ultimately, the occurrence of these
redwood fossils in Inner Mongolia is consistent with a weak or muted Eastern Asian summer monsoon in the
region with the absence of an elevated Mongolian plateau during the early Miocene. A shift of moisture sources
for the region accompanying the change from a Westerlies-dominated climate to the present-day monsoondominated
climate system occurred after the early Miocene time.
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# Funding_Agency
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# Site_Information
#   Site_Name: Hannuoba Formation
#   Location: Mongolia
#   Northernmost_Latitude: 40.7619
#   Southernmost_Latitude: 40.7619
#   Easternmost_Longitude: 112.8392
#   Westernmost_Longitude: 112.8392
#   Elevation_m: 
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# Data_Collection
#   Collection_Name: mongolia_si_liang2022
#   First_Year: 21090000
#   Last_Year: 21090000
#   Time_Unit: calendar year before present
#   Core_Length_m: 
#   Parameter_Keywords: carbon dioxide
#   Notes: 
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# Chronology_Information 
# Chronology: 
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# Variables
# PaST_Thesaurus_Download_Resource: https://www.ncei.noaa.gov/access/paleo-search/skos/past-thesaurus.rdf
#   PaST_Thesaurus_Download_Description: Paleoenvironmental Standard Terms (PaST) Thesaurus terms, definitions, and relationships in SKOS format.
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# Data variables follow that are preceded by "##" in columns one and two.
# Variables list, one per line, shortname-tab-var components: what, material, error, units, seasonality, data type, detail, method, C or N for Character or Numeric data)
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# Data:
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# Data line format - tab-delimited text, variable short name as header
# Missing_Values: NA
proxy	first_author_last_name	publication_year	doi	age_ka	Age_uncertainty_pos_ka	Age_uncertainty_neg_ka	CO2_ppm	CO2_uncertainty_pos_ppm	CO2_uncertainty_neg_ppm	person who entered data	email of individual entering the data	Reference of the data product	doi	Sample name	Family	Genus	Species	"Sample Repository"	"Geologic Formation"	Stratigraphic level	Age (Ma)	Age uncertainty, old (Ma)	Age uncertainty, young (Ma)	Age scale (GTS20XX)	How was age determined?	Modern Latitude (decimal degree, south negative)	Modern Longitude (decimal degree, west negative)	Paleo Latitude (decimal degree, south negative)	Paleo Longitude (decimal degree, west negative)	Number of stomatal counts per leaf	Number of leaves comprising CO2 estimate	"Counting Method (Image, microscope)"	"Counting box dimensions (µm × µm)"	# Stomata	# Epidermal Cells	"Sample mean stomatal density (SD, mm-2)"	"Sample mean stomatal index (SI, %)"	SD error (+/- 1 s.e.m.)	SI error (+/- 1 s.e.m.)	Modern Calibration species	"Modern Calibration Regression Equation"	"Calibration Error"	Reported mean CO2	CO2 type	"Reported CO2 Uncertainty (Low)"	"Reported CO2 Uncertainty (High)"	What is the uncertainty range?	What is the distribution of the uncertainties?	general notes
stomata-SI	Liang	2022	10.1016/j.revpalbo.2022.104743	21090	1740	1740	307	NA	NA	Dana Royer	droyer@wesleyan.edu	Liang, J., Leng, Q., Xiao, L., Höfig, D. F., Royer, D. L., Zhang, Y. G., and Yang, H., 2022, Early Miocene redwood fossils from Inner Mongolia: CO2 reconstructions and paleoclimate effects of a low Mongolian plateau: Review of Palaeobotany and Palynology, v. 305, p. 104743, doi: 10.1016/j.revpalbo.2022.104743.	10.1016/j.revpalbo.2022.104743	NA	Cupressaceae	Metasequoia	sp.	Geological Museum at Chang’an University, Xi’an, China	Hannuoba Formation 	NA	21.09	22.83	19.35	NA	Combination of radiometric ages (multiple K-Ar dates) and biostratigraphy	NA	NA	NA	NA	1	10	microscope	0.04 - 0.16 mm^2				12.59		0.74	Metasequoia glyptostroboides	Beerling et al. (2009)	uncertainties following the resampling procedure in Beerling et al. (2009)	307	median	NA	NA	Seven out of the ten measurements of stomatal index are higher than what is captured in the present-day calibration; as a result, the percentiles computed with the Monte Carlo simulations are not robust	NA	NA