/* DATA DESCRIPTION:
Citation:	Chu, Yongzhi; Li, Xiaohu; Xie, Ruifang C; Conway, Tim M; Xu, Antao; Dong, Yanhui (2026): Measured iron isotopic compositions of Fe-Mn crust sample CXD31 [dataset]. PANGAEA, https://doi.pangaea.de/10.1594/PANGAEA.991015 (DOI registration in progress)
Abstract:	Iron (Fe) is a key micronutrient regulating marine productivity and the global carbon cycle, yet reconstructing the relative contributions of different Fe sources through time remains challenging. Here we present high-resolution iron isotopic compositions (δ56Fe), measured by multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS), from a Fe-Mn crust sample (CXD31) recovered from the North Pacific Ocean, spanning the past ~23 Myr. The Fe isotopic values vary within the range of modern marine Fe sources, reflecting dynamic mixing among atmospheric dust, sedimentary inputs, and hydrothermal contributions. Using isotope mass-balance calculations, we reconstruct temporal changes in the relative importance of these Fe sources since the Miocene. Three intervals characterized by elevated δ56Fe values (~16.9, ~11.6, and ~2.7 Ma) indicate enhanced inputs of isotopically heavy Fe, which we attribute to increased aeolian dust supply linked to progressive aridification of inland Asia. These Fe isotope data provide a long-term record of Fe source variability in the North Pacific and offer new constraints on the coupling between continental climate evolution and oceanic Fe cycling.
Keyword(s):	Aeolian dust; Ferromanganese crust; Iron biogeochemsitry; Isotopic fingerprinting; Marine geochemistry; North Pacific
Funding:	National Key Research and Development Program of China, grant/award no. 2023YFC2811205
	National Key Research and Development Program of China, grant/award no. 2023YFC2811305
	National Natural Science Foundation of China (NSFC) (URI: https://www.nsfc.gov.cn/english/site_1/index.html), grant/award no. 42376035
	National Natural Science Foundation of China (NSFC) (URI: https://www.nsfc.gov.cn/english/site_1/index.html), grant/award no. U2244222
	Second Institute of Oceanography, State Oceanic Administration, grant/award no. SZ2563
Coverage:	LATITUDE: 19.900000 * LONGITUDE: 173.200000
	DATE/TIME START: 2003-07-19T00:00:00 * DATE/TIME END: 2003-07-19T00:00:00
	MINIMUM ELEVATION: -1357.0 m * MAXIMUM ELEVATION: -1357.0 m
Event(s):	DY105-12/14_CXD31 (CXD31) * LATITUDE: 19.900000 * LONGITUDE: 173.200000 * DATE/TIME: 2003-07-19T00:00:00 * ELEVATION: -1357.0 m * METHOD/DEVICE: Dredge, rock (DRG_R) * COMMENT: Fe–Mn crust collected by rock dredging on a seamount slope
Parameter(s):	Age [Ma] (Age) * PI: Chu, Yongzhi (https://orcid.org/0000-0002-2549-0670)
	δ56Fe [‰] (δ56Fe) * PI: Chu, Yongzhi (https://orcid.org/0000-0002-2549-0670) * METHOD/DEVICE: Multiple-collector inductively coupled plasma mass spectrometer (MC-ICPMS)
	δ56Fe, standard deviation [±] (δ56Fe std dev) * PI: Chu, Yongzhi (https://orcid.org/0000-0002-2549-0670) * METHOD/DEVICE: Multiple-collector inductively coupled plasma mass spectrometer (MC-ICPMS) * COMMENT: 2 SD
License:	Creative Commons Attribution 4.0 International (CC-BY-4.0) (URI: https://creativecommons.org/licenses/by/4.0/)
Status:	Curation Level: Enhanced curation (URI: https://wiki.pangaea.de/wiki/Curation_levels)
Size:	78 data points
*/
Age [Ma]	δ56Fe [‰]	δ56Fe std dev [±]
0.20	-0.33	0.05
0.91	-0.24	0.03
1.77	-0.28	0.03
2.37	-0.27	0.01
3.24	-0.39	0.03
4.21	-0.38	0.02
4.68	-0.37	0.01
5.47	-0.73	0.02
6.82	-0.40	0.04
7.57	-0.45	0.02
8.15	-0.48	0.05
8.92	-0.57	0.02
9.37	-0.20	0.00
10.14	-0.43	0.05
11.51	-0.14	0.02
12.28	-0.12	0.02
12.92	-0.38	0.01
13.35	-0.61	0.02
13.71	-0.40	0.03
14.82	-0.47	0.02
15.78	-0.36	0.04
17.21	-0.16	0.03
18.02	-0.42	0.04
18.73	-0.30	0.02
19.91	-0.37	0.04
20.40	-0.19	0.04