Richard J. Moscati
Leonid A. Neymark
20210722
In situ U-Pb dating of apatite and rutile from St. Francois Mountains IOA and IOCG deposits, southeast Missouri
CSV
Denver, CO
U.S. Geological Survey
Additional information about Originators: Richard Moscati, https://orcid.org/0000-0002-0818-4401; Leonid Neymark, https://orcid.org/0000-0003-4190-0278. Suggested citation: Moscati, R.J., and Neymark, L.A., 2021, In situ U-Pb dating of apatite and rutile from St. Francois Mountains IOA and IOCG deposits, southeast Missouri: U.S. Geological Survey data release, https://doi.org/10.5066/P9EEV8E7.
https://doi.org/10.5066/P9EEV8E7
Apatite (Ca5(PO4)3(Cl/F/OH)) and rutile (TiO2) samples were collected by the U.S. Geological Survey (USGS) from the iron oxide-apatite-rare earth element (IOA-REE) and iron oxide-copper-gold (IOCG) deposits hosted by the Mesoproterozoic, St. Francois Mountains terrane, southeast Missouri. Samples were prepared and analyzed for direct age dating on a laser ablation inductively coupled plasma mass spectrometer (LA-ICP-MS) system at the USGS in Denver, Colorado from May 2016 to June 2019.
These data present the first LA-ICP-MS U-Pb dating results for apatite and rutile from Pilot Knob, Bourbon, Kratz Spring, Iron Mountain, Boss-Bixby, and Pea Ridge deposits located within the Mesoproterozoic, St. Francois Mountains terrane, southeast Missouri. The data set was also obtained to further demonstrate the practical application of the LA-ICP-MS analytical procedure for U-Pb dating of apatite and rutile.
Bracciali, L., Parrish, R.R., Horstwood, M.S.A., Condon, D.J., and Najman, Y., 2013, U-Pb LA-(MC)-ICP-MS dating of rutile: New reference materials and applications to sedimentary provenance, Chemical Geology, v. 347, p. 82-101, https://doi.org/10.1016/j.chemgeo.2013.03.013.
Hu, Z., Gao, S., Liu, Y., Hu, S., Chen, H. and Yuan, H., 2008, Signal enhancement in laser ablation ICP-MS by addition of nitrogen in the central channel gas: Journal of Analytical Atomic Spectrometry, v. 23, p. 1093-1101, https://doi.org/10.1039/B804760J.
Ludwig, K.R., 2012, User's Manual for Isoplot Version 3.75-4.15--A Geochronological Toolkit for Microsoft Excel: Berkeley Geochronological Center Special Publication no. 5 (rev. 2012), 75 p., available at https://www.bgc.org/isoplot
Neymark, L.A., Holm-Denoma, C.S., Pietruszka, A.J., Aleinikoff, J.N., Fanning, C.M., Pillers, R.M., and Moscati, R.J., 2016, High spatial resolution U-Pb geochronology and Pb-isotope geochemistry of magnetite-apatite ore from the Pea Ridge iron oxide-apatite (IOA) deposit, St. Francois Mountains, southeast Missouri, USA: Economic Geology, v. 111, no. 8, p. 1915-1933, https://doi.org/10.2113/econgeo.111.8.1915.
Paton, C., Hellstrom, J., Paul, B., Woodhead, J., and Hergt, J., 2011, Iolite: Freeware for the visualization and processing of mass spectrometric data, Journal of Analytical Atomic Spectrometry: v. 26, p. 2508-2518, https://doi.org/10.1039/c1ja10172b.
Schoene, B., and Bowring, S.A., 2006, U-Pb systematics of the McClure Mountain syenite: Thermochronological constraints on the age of the 40Ar/39Ar standard MMhb: Contributions to Mineralogy and Petrology, v. 151, p. 615-630, https://doi.org/10.1007/s00410-006-0077-4.
Stacey, J.S., and Kramers, J.D., 1975, Approximation of terrestrial lead isotope evolution by a two-stage model: Earth and Planetary Science Letters, v. 26, no. 2, p. 207-221, https://doi.org/10.1016/0012-821X(75)90088-6.
Tera, F., and Wasserburg, G.J., 1972, U-Th-Pb systematics in three Apollo 14 basalts and the problem of initial Pb in lunar rocks: Earth and Planetary Science Letters, v. 14, no. 3, p. 281-304, https://doi.org/10.1016/0012-821X(72)90128-8.
2016
2019
ground condition
None planned
-91.4167
-90.6334
38.2645
37.6192
ISO 19115 Topic Category
geoscientificInformation
USGS Thesaurus
geochronology
uranium
thorium
lead
mineral deposits
uranium-lead analysis
None
Geology, Geophysics, and Geochemistry Science Center
apatite
MRP
laser ablation inductively coupled plasma mass spectrometer
LA-ICP-MS
U-Pb
U.S. Geological Survey
USGS
Mineral Resources Program
GGGSC
rutile
MRDS
Pilot Knob
Bourbon
Kratz Spring
Boss-Bixby
Pea Ridge
GNIS
Washington County
Iron County
Dent County
Crawford County
Franklin County
Saint Francois County
USGS Metadata Identifier
USGS:5fd7a280d34e30b9123cb492
Common Geographic Areas
southeast Missouri
USGS Thesaurus: Time Periods
Mesoproterozoic
None. Please see the Distribution Information section for details.
Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although these data have been processed successfully on a computer system at the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. The USGS or the U.S. Government shall not be held liable for improper or incorrect use of the data described and/or contained herein. Acknowledgment of the U.S. Geological Survey would be appreciated in products derived from these data.
Richard J Moscati
U.S. Geological Survey, ROCKY MOUNTAIN REGION
Geologist
mailing and physical
Mail Stop 963, W 6th Ave Kipling St
Denver
CO
80225
US
303-236-0023
rmoscati@usgs.gov
Sample preparation and laboratory analyses were completed in accordance with standard operating procedures in generating the geochronological data. Data were reviewed for consistency and analyses results were checked for validity. The data is sensitive to significant figures and some cell values have trailing zeros in decimals. Due to the table being CSV format, when read into MS Excel the software will truncate the trailing zeros off the decimal, which may lead to an impression of analytical accuracy that does not actually exist. There is no possible solution in the software other than reading in all fields as text instead of numbers. This is purely a software display issue; values in the CSV file are intact and correct.
No formal logical accuracy tests were conducted. Due to the table being CSV format, when read into MS Excel the software may display some fields’ values using scientific notation. This is evident in the U_ppm and Th_ppm fields, but does not occur in the other fields.
Data set is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details.
The latitude and longitude values of the drill core samples are precise to 4 decimal places.
No formal positional accuracy tests were conducted.
Apatite and rutile samples for this study were collected by and obtained from Warren Day, John Slack, and Corey Meighan (all of USGS, Denver). Polished thin sections were prepared from drill core and rock samples.
201906
Apatite samples were ablated directly from polished thin sections and rutile samples were ablated in the form of mounted loose grains with a Photon Machines Excite™ 193 nm ArF excimer laser in spot mode (150 total bursts) with a repetition rate of 5 Hz, laser energy of 3.5 mJ, and an energy density of 3-5 J/cm2. The laser spot sizes were 50 to 135 µm for both apatite and rutile depending on the U content. The rate of He gas flow to the HelEx cell of the laser (sample chamber) was 0.3-0.6 L/min, and make-up Ar gas (0.2-0.3 L/min) was added to the sample stream prior to its introduction into the plasma. Nitrogen was added to the sample stream at a flow rate of 5.5 mL/min (Hu and others, 2008), which allowed for significant reduction in ThO+/Th+ (<0.5%) and improved the ionization of refractory Th. With the magnet parked at a constant mass, the flat tops of the isotope peaks were measured at the following masses by rapidly deflecting the ion beam: 202Hg, 204(Hg+Pb), 206Pb, 207Pb, 208Pb, 232Th, 235U, and 238U with a 30 s on-peak background measured prior to each 45-s analysis. For high-Th samples (some apatite grains), the 232Th peak was excluded from the analytical sequence to avoid ion-beam attenuation.
201906
Raw data were reduced off-line using the Iolite™ 2.5 program (Paton and others, 2011) to subtract on-peak background signals, correct for U-Pb downhole fractionation, normalize for the instrumental mass bias, and obtain estimates of U and Th concentrations in unknowns. Several secondary matrix-matched standards were used for apatite including MMAp (525.1 ± 1.8 Ma apatite in syenite from McClure Mountain, Colorado; Schoene and Bowring, 2006). Two rutile samples from granulite facies metasedimentary rocks, Sugluk-4 (1719 ± 14 Ma, Quebec, Canada) and PCA-S207 (1865.0 ± 7.5 Ma, Saskatchewan, Canada; both described in Bracciali and others, 2013), were used as matrix-matched reference materials for rutile analyses.
Biased ages of the matrix-matched reference materials measured in the same analytical sessions as the unknowns were estimated by constructing Tera-Wasserburg (T-W) isochrons (Tera and Wasserburg, 1972) using NIST glass-corrected Pb isotope and U/Pb ratios. Then, these biased ages and their true values were used to derive correction factors (F) for the U/Pb ratios in each analytical session using the formula, (where the asterisk is used to denote the common-Pb corrected value):
F = (206Pb*/238U Age)true / (206Pb*/238U Age)biased
For each analytical session, measured individual 238U/206Pb ratios obtained from Iolite™ output were corrected using the corresponding F values and the formula:
(238U/ 206Pb)corrected = F × (206Pb/238U)measured
Finally, these corrected 238U/ 206Pb and Iolite™ 207Pb/206Pb ratios were used to construct T-W isochrons for unknown materials. Ages and their uncertainties were calculated using Isoplot 4.15 program (Ludwig, 2012). This data-reduction protocol was successfully applied to LA-ICPMS apatite analyses from previous studies (e.g., Neymark et al., 2016). 206Pb/238U ages were calculated from the bias-corrected U/Pb ratios applying 207Pb-based common Pb correction using Stacey-Kramers model (Stacey and Kramers, 1975) 207Pb/206Pb value.
201906
The southeast Missouri samples were collected by Warren Day, John Slack, and Corey Meighan (all of the USGS). Location data is given in SE MO Data Table.csv.
Point
0.0001
0.0001
Decimal degrees
WGS_1984
WGS_84
6378137.0
298.257223563
SE MO Data Table.csv
Comma Separated Value (CSV) file containing data.
U.S. Geological Survey
SampleID
Sample collection number as collected in field.
U.S. Geological Survey
Alphanumeric label assigned by collector.
Spot_number
Laboratory laser spot number within a batch analysis.
U.S. Geological Survey
Alphanumeric value composed of prefix Spot with spot number.
TRA_File
Time Resolved Analysis file number.
U.S. Geological Survey
Alphanumeric value composed of prefix T- with TRA file number.
Mineral
Analyzed mineral phase.
U.S. Geological Survey
rutile
TiO2
Producer defined
apatite
Ca5(PO4)3(Cl/F/OH)
Producer defined
U_ppm
Measured uranium concentration in ppm (parts per million).
U.S. Geological Survey
0.0559
2990
ppm (parts per million).
Th_ppm
Measured thorium concentration in ppm (parts per million). A value of -9999 indicates the value was not determined.
U.S. Geological Survey
0.00041
1403
ppm (parts per million).
238U_206Pb
Down hole corrected and sample-standard bracketed 238U/206Pb ratio.
U.S. Geological Survey
0.07
27.38
2SE_238U_206Pb
Plus/minus two sigma (absolute uncertainty) for 238U/206Pb ratio.
U.S. Geological Survey
0.01
6.04
207Pb_206Pb
Down hole corrected and sample-standard bracketed 207Pb/206Pb ratio.
U.S. Geological Survey
0.058
0.925
2SE_207Pb_206Pb
Plus/minus two sigma (absolute uncertainty) for 207Pb/206Pb ratio.
U.S. Geological Survey
0.00043
0.088
Rho
Correlation coefficient between the uncertainties of the ratio of 238U to 206Pb and the ratio of 207Pb to 206Pb calculated by Iolite™ (Paton and others, 2011).
U.S. Geological Survey
-0.979
0.939
206Pb_238U
Down hole corrected and sample-standard bracketed 206Pb/238U ratio.
U.S. Geological Survey
0.0365
15.0129
2SE_206Pb_238U
Plus/minus two sigma (absolute uncertainty) for 206Pb/238U ratio.
U.S. Geological Survey
0.0016
2.5816
207Pbcorr_Pb206_U238_Date
Down hole corrected and sample-standard bracketed 206Pb/238U date, with 207Pb as the index isotope for common-Pb correction, in Mega annum (Ma). A value of -9999 indicates that the calculated date is an outlier.
U.S. Geological Survey
0
2952
Mega annum (Ma).
2SE_207Pbcorr_Pb206_U238_Date
Plus/minus two sigma (absolute uncertainty) for 206Pb/238U date, with 207Pb as the index isotope for common-Pb correction, in Mega annum (Ma). A value of -9999 indicates that the associated calculated date for this error is an outlier.
U.S. Geological Survey
23
3117
Mega annum (Ma).
Latitude
Latitude of sample collection locality in datum WGS 84.
U.S. Geological Survey
37.6192
38.2645
Decimal degrees
Longitude
Longitude of sample collection locality in datum WGS 84.
U.S. Geological Survey
-91.4167
-91.1582
Decimal degrees.
U.S. Geological Survey
GS ScienceBase
mailing address
Denver Federal Center, Building 810, Mail Stop 302
Denver
CO
80225
United States
1-888-275-8747
sciencebase@usgs.gov
Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty.
https://www.sciencebase.gov/catalog/item/5fd7a280d34e30b9123cb492
20210722
Richard J Moscati
U.S. Geological Survey, ROCKY MOUNTAIN REGION
Geologist
mailing and physical
Mail Stop 963, W 6th Ave Kipling St
Denver
CO
80225
USA
303-236-0023
rmoscati@usgs.gov
Content Standard for Digital Geospatial Metadata
FGDC-STD-001-1998