# Paleo-pCO2 Database Piceance Creek Basin Eocene Nahcolite CO2 Data
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# NOTE: Please cite Publication, and Online_Resource and date accessed when using these data. 
# If there is no publication information, please cite Investigators, Title, and Online_Resource and date accessed. 
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# Online_Resource: https://www.ncdc.noaa.gov/paleo/study/23531
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# Online_Resource: https://www1.ncdc.noaa.gov/pub/data/paleo/climate_forcing/trace_gases/Paleo-pCO2/jagniecki2015nahcolite.txt
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# Archive: Climate Forcing
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# Dataset DOI: 
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# Parameter_Keywords: carbon dioxide
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# Contribution_Date
#	Date: 2018-03-08
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# File_Last_Modified_Date
#	Date: 2020-02-25
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# Title
#	Study_Name: Paleo-pCO2 Database Piceance Creek Basin Eocene Nahcolite CO2 Data
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# Investigators
#	Investigators: Jagniecki, E.A.; Lowenstein, T.K.; Jenkins, D.M.; Demicco, R.V.
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# Description_Notes_and_Keywords
#	Description: Paleo-CO2 derived from Eocene nahcolite from a Piceance Creek Basin, Colorado sediment core (Green River Formation), contributed to the Paleo-pCO2 Database. 
#	File updated February 2020 - new Paleo-pCO2 Database format
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# Publication 
#	Authors: Elliot A. Jagniecki, Tim K. Lowenstein, David M. Jenkins, Robert V. Demicco
#	Published_Date_or_Year: 2015-12-01     
#	Published_Title: Eocene atmospheric CO2 from the nahcolite proxy
#	Journal_Name: Geology
#	Volume: 43
#	Edition: 
#	Issue: 12
#	Pages: 1075-1078
#	Report_Number: 
#	DOI: 10.1130/G36886.1
#	Online_Resource: https://pubs.geoscienceworld.org/gsa/geology/article-abstract/43/12/1075/131750/eocene-atmospheric-co2-from-the-nahcolite-proxy
#	Full_Citation: 
#	Abstract: Estimates of the atmospheric concentration of CO2, [CO2]atm, for the "hothouse" climate of the early Eocene climatic optimum (EECO) vary for different proxies. Extensive beds of the mineral nahcolite (NaHCO3) in evaporite deposits of the Green River Formation, Piceance Creek Basin, Colorado, USA, previously established [CO2]atm for the EECO to be >1125 ppm by volume (ppm). Here, we present experimental data that revise the sodium carbonate mineral equilibria as a function of [CO2] and temperature. Co-precipitation of nahcolite and halite (NaCl) now establishes a well-constrained lower [CO2]atm limit of 680 ppm for the EECO. Paleotemperature estimates from leaf fossils and fluid inclusions in halite suggest an upper limit for [CO2]atm in the EECO from the nahcolite proxy of ~1260 ppm. These data support a causal connection between elevated [CO2]atm and early Eocene global warmth, but at significantly lower [CO2]atm than previously thought, which suggests that ancient climates on Earth may have been more sensitive to a doubling of [CO2]atm than is currently assumed.
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# Publication 
#	Authors: Tim K. Lowenstein, Robert V. Demicco 
#	Published_Date_or_Year: 2006-09-26
#	Published_Title: Elevated Eocene Atmospheric CO2 and Its Subsequent Decline
#	Journal_Name: Science 
#	Volume: 313
#	Edition: 
#	Issue: 5795
#	Pages: 1928
#	Report_Number: 
#	DOI: 10.1126/science.1129555 
#	Online_Resource: http://science.sciencemag.org/content/313/5795/1928
#	Full_Citation: 
#	Abstract: Quantification of the atmospheric concentration of CO2 ([CO2]atm) during warm periods of Earth's history is important because burning of fossil fuels may produce future [CO2]atm approaching 1000 parts per million by volume (ppm). The early Eocene (~56 to 49 million years ago) had the highest prolonged global temperatures of the past 65 million years. High Eocene [CO2]atm is established from sodium carbonate minerals formed in saline lakes and preserved in the Green River Formation, western United States. Coprecipitation of nahcolite (NaHCO3) and halite (NaCl) from surface waters in contact with the atmosphere indicates [CO2]atm > 1125 ppm (four times preindustrial concentrations), which confirms that high [CO2]atm coincided with Eocene warmth.
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# Site_Information 
#	Site_Name: Shell 23x-2
#	Location: North America>United States Of America>Colorado
#	Country: United States Of America
#	Northernmost_Latitude: 39.90546
# 	Southernmost_Latitude: 39.90546
# 	Easternmost_Longitude: -108.36224
# 	Westernmost_Longitude: -108.36224
# 	Elevation:  2000 m
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# Data_Collection   
#	Collection_Name: Jagniecki2015nahcolite
#	Earliest_Year: 51550000
#	Most_Recent_Year: 49320000
#	Time_Unit: Cal. Year BP
#	Core_Length: 
#	Notes: 
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# Chronology_Information
#	Chronology: Ar-Ar:   Smith et al. 2008, doi: 10.1130/B26073.1   Smith et al. 2015, doi: 10.1007/978-94-017-9906-5_4.
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# Variables 
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# Data:
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										REFERENCE AND CONTACT INFORMATION				SAMPLE IDENTIFICATION										AGE CONSTRAINTS						ANALYTICAL SPECIFICATIONS											
proxy	first_author_last_name	publication_year	doi	age_ka	Age_uncertainty_pos_ka	Age_uncertainty_neg_ka	CO2_ppm	CO2_uncertainty_pos_ppm	pCO2_uncertainty_neg_ppm	Name	Contact	Citation	DOI	GSN#	Site	Hole	Core	Top m	Bottom m	Site Latitude	Site Longitude	Site Elevation	description of depositional environment	Age 	Age uncert. ±1 s.d.	Age method	Age Model Ref	Age Model doi	Age Model Notes	Predominant sodium carbonate mineral	method of analysis	pCO2	±error pCO2 (ppmv)	Explanation of error pCO2	calibration equation	reference for calibration equation	comments	Temperature (°C)	±error Temperature (°C)	Method for temperature determination	Reference for temperature determination
										Name of individual entering the data	E-mail address	Published reference of data	DOI link to reference	Geologic sample number (http://www.geosamples.org)	site number	Core repository identifier	Core repository identifier	"Interval, from core log"	"Interval, from core log"	Current latitude of site (°N/S)	Current longitude of site (degrees °E/W)	current elevation (m above sea level)		(Ma before present)	Uncertainty in age from age model (Ma)	"e.g.:  biostratigraphy, magnetic polarity, radiometric etc."	if different from primary DOI	Doi if different from primary reference	Any additional notes or method info.			Reconstructed atmospheric pCO2  (ppmv)	propagated		equation used for determining pCO2			used to calculate atmospheric pCO2	"s.d. or sem, whatever reflects certainty in value"		
nahcolite	Jagniecki	2015	10.1130/G36886.1	50435	1655	1445	680-1260	NA	0	Tim Lowenstein	lowenst@binghamton.edu	Jagniecki et al. 2015	10.1130/G36886.1	"N/A,  Piceance Creek Basin, Green River Formation"	Shell 23x-2 core	NA	"CO42- USGS Core Research Center, Denver"	561	NA	"39?54'19.67"" N"	"108?21'44.06"" W"	2000	Primary sedimentary structures in perennial alkaline saline lake	"51.55 bottom
49.32 top"	"± 0.54
± 0.33"	Ar-Ar	"Smith et al. 2008 doi: 10.1130/B26073.1        Smith et al. 2015,doi 10.1007/978-94-017-9906-5_4."	NA	NA	Nahcolite + Halite	x-ray diffraction analysis	680-1260	NA	NA	CO2 = 170e0.0713T	dx.doi.org/10.1130/G36886.1	NA	19.5-28.0	NA	fluid inclusions in halite from LaClair and Lowenstein 2010	"LaClair, D., and Lowenstein, T.K., 2010, Using microthermometry, laser Raman spectroscopy and evaporites to reconstruct the paleoclimate of the Eocene Green River Formation, Colorado, USA, in Proceedings of the 10th Biennial Pan-American Current Research on Fluid Inclusions, University of Nevada Las Vegas, Las Vegas, Nevada, 7–1 June 2010, p. 51–52."