# Panama Basin Thorium and Uranium Sediment Data for the Last 25,000 Years
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#              World Data Center for Paleoclimatology, Boulder 
#                                  and 
#                       NOAA Paleoclimatology Program 
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# NOTE: Please cite original publication, online resource and date accessed when using this data.
# If there is no publication information, please cite Investigator, title, online resource and date accessed.
#
#  Online_Resource: http://www.hurricane.ncdc.noaa.gov/pls/paleox/f?p=519:1:::::P1_STUDY_ID:15326
# 
# Original_Source_URL: ftp://ftp.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/singh2011/singh2011-rc8-102.txt
#
# Archive: Paleoceanography
#
#--------------------------------
# Contribution_Date
# Date: 2013-10-30
#--------------------------------
# Title: Panama Basin Thorium and Uranium Sediment Data for the Last 25,000 Years
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# Investigators: Singh, A.; Marcantonio, F.; Lyle, M.
#--------------------
# Description and Notes
#   Description: Standard uranium series analysis by inductively-coupled plasma mass spectrometry was used.
#
#--------------------
# Publication 
#   Authors: Singh, A., F. Marcantonio and M. Lyle
#   Journal_Name: Earth and Planetary Science Letters
#   Published_Title: Sediment focusing in the Panama Basin, Eastern Equatorial Pacific Ocean
#   Published_Date_or_Year: 2011
#   Volume: 309
#   Pages: 33-44
#   DOI: 
# Abstract: Age-model derived sediment mass accumulation rates (MARs) are consistently higher than 230Th-normalized MARs in the Equatorial Pacific Ocean during the past 25 ka. The offset, being highest in the Panama Basin, suggests a significant role for deep-sea sediment redistribution (i.e., sediment focusing) in this region. Here, we test the hypothesis that downslope transport of sediments from topographically high regions that surround the Panama Basin is the cause of higher-than-expected xs230Th inventories over the past 25 ka in the deeper parts of the basin. We find little difference in xs230Th inventories between the highest and lowest reaches of the basin. Furthermore, there is no correlation between xs230Th-derived sediment focusing factors and water depth which suggests that the topographic highs do not serve as a source of xs230Th. A spatial analysis suggests that there may be an enhanced scavenging effect on xs230Th concentrations in sediment closest to the equator whe! re productivity is the highest, although further data is necessary to corroborate this. At the equator xs230Th-derived focusing factors are high and range from about 1 to 5 during the Holocene and about 1 to 11 during the last glacial. In contrast, non-equatorial cores show a smaller range in variability from about 0.7 to 2.8 during the Holocene and from 0.7 to 3.6 during the last glacial. Based on 232Th flux measurements, we hypothesize that the location at which eolian detrital fluxes surpass the riverine detrital fluxes is approximately 300 km from the margin. While riverine fluxes from coastal margins were higher during the Holocene, eolian fluxes were higher during the last glacial.
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# Funding_Agency: 
#    Funding_Agency_Name: National Science Foundation
#    Grant: OCE-0851056
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# Site Information: 
# 	Site_Name: RC8-102
#   	Location: Eastern Pacific Ocean
#	 Northernmost_Latitude:  -1.4
# 	 Southernmost_Latitude:  -1.4
# 	 Easternmost_Longitude:  -86.8
#  	Westernmost_Longitude:   -86.8
# 	Elevation: -2180
#--------------------------------
# Data Collection 
# 	Collection_Name: RC8-102 Singh11
# 	Oldest_Year: 23800
# 	Most_Recent_Year: 4900
# 	Time_Unit: cal yr BP
# 	Core_Length:
# 	Notes: The age model for RC8-102 is based on oxygen isotope records of planktonic foraminfera (G. sacculifer and G. ruber) and 10 planktonic radiocarbon dates (N. dutertrei: Koutavas and Lynch-Stieglitz, 2003).
#
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# 	Chronology:
#     
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# Variables    
# 
# 	Data variables follow (have no #)
# 	Data line variables format: one per line, shortname- 9 components: what, material, error, units, seasonality, archive, detail, method, C or N for Character or Numeric data) 
## depth_cm	Depth,,,cm,,,,,N
## age_calBP	Age,,,cal yr BP,,,,,N
## 238U	Uranium-238,,,dpm/g,,paleoceanography,,,N
## xs230Th	Thorium-230 excess,,,dpm/g,,paleoceanography,,,N
## 232Th	Thorium-232,,,dpm/g,,paleoceanography,,,N
#--------------------------------
# Data:
depth_cm	age_calBP	238U	xs230Th	232Th
2	5600	0.73	4.22	0.1	
15	9050	5.14	3.85	0.1	
45	15500	4.65	2.04	0.05	
60	17850	2.53	3.19	0.09	
75	19800	2.73	3.3	0.09	
105	23800	5.93	2.43	0.09