Citation:

PANGAEA.996097 (dataset in review)

Name: Whole-Rrock major oxide geochemistry and titrated ferrous iron (Fe2+) dataset of hydrothermally altered serpentinites and metasomatites from the Onnuri Oceanic Core Complex
License: https://creativecommons.org/licenses/by/4.0/
Keywords: Bulk-rock geochemistry; Ferrous iron titration; ICP-OES; Iron oxidation state; Major oxides; Metasomatic zonation; Redox baseline

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Abstract:

Whole-rock major element concentrations (wt.%), loss on ignition (LOI), and titrated ferrous iron (FeO) measurements were used to establish total iron oxidation states (Fe³⁺/Fe_total). Samples were collected from seafloor detachment surfaces of the Onnuri Oceanic Core Complex, Central Indian Ridge, during the 2019 and 2022 R/V ISABU dredge operations (RD1912, RD1913, RD2208). The aim was to characterize the bulk-rock geochemical transition, hydration states, and chemical redox fluctuations associated with the pervasive replacement of background serpentinites into talc-rich suites. Pulverized rock powders (400 mesh) were analyzed at Actlabs (Canada). Major oxide abundances were determined by lithium metaborate/tetraborate fusion followed by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), whereas ferrous iron (FeO) contents were independently quantified using cold acid digestion (V₂O₅-HF) and subsequent potassium dichromate colorimetric titration.

Keyword(s):

Bulk-rock geochemistry; Ferrous iron titration; ICP-OES; Iron oxidation state; Major oxides; Metasomatic zonation; Redox baseline

Coverage:

Median Latitude: -11.420718 * Median Longitude: 66.401321 * South-bound Latitude: -11.428260 * West-bound Longitude: 66.378405 * North-bound Latitude: -11.413095 * East-bound Longitude: 66.421243

Minimum DEPTH, sediment/rock: 0 m * Maximum DEPTH, sediment/rock: 0 m

Event(s):

RD1912_DREG * Latitude Start: -11.413095 * Longitude Start: 66.418228 * Latitude End: -11.414573 * Longitude End: 66.421243 * Elevation Start: -2162.0 m * Elevation End: -2045.0 m * Method/Device: Dredge (DRG) * Comment: Geomorphology: Detachment fault surface. Lithology: Diabase, Gabbro, Serpentinite

RD1913_DREG * Latitude Start: -11.428260 * Longitude Start: 66.378405 * Latitude End: -11.426827 * Longitude End: 66.381727 * Elevation Start: -3133.0 m * Elevation End: -2984.0 m * Method/Device: Dredge (DRG) * Comment: Geomorphology: Detachment fault surface. Lithology: Serpentinite

RD2208_DREG * Latitude: -11.420833 * Longitude: 66.407000 * Elevation: -2160.0 m * Method/Device: Dredge (DRG) * Comment: Geomorphology: Detachment fault surface. Lithology: Diabase, Serpentinite, Talc-rich metasomatite, Breccia

Parameter(s):

#	Name	Short Name	Unit	Principal Investigator	Method/Device	Comment
1	Event label	Event		Choi, Sarang
2	DEPTH, sediment/rock	Depth sed	m	Choi, Sarang		Geocode
3	Lithology/composition/facies	Lithology		Choi, Sarang
4	Sample number	Sample no		Choi, Sarang
5	Silicon dioxide	SiO2	%	Choi, Sarang	ICP-OES, Inductively coupled plasma - optical emission spectrometry	wt. %
6	Aluminium oxide	Al2O3	%	Choi, Sarang	ICP-OES, Inductively coupled plasma - optical emission spectrometry	wt. %
7	Iron oxide, Fe2O3	Fe2O3	%	Choi, Sarang	ICP-OES, Inductively coupled plasma - optical emission spectrometry	wt. %, total
8	Titanium dioxide	TiO2	%	Choi, Sarang	ICP-OES, Inductively coupled plasma - optical emission spectrometry	wt. %
9	Magnesium oxide	MgO	%	Choi, Sarang	ICP-OES, Inductively coupled plasma - optical emission spectrometry	wt. %
10	Calcium oxide	CaO	%	Choi, Sarang	ICP-OES, Inductively coupled plasma - optical emission spectrometry	wt. %
11	Sodium oxide	Na2O	%	Choi, Sarang	ICP-OES, Inductively coupled plasma - optical emission spectrometry	wt. %
12	Potassium oxide	K2O	%	Choi, Sarang	ICP-OES, Inductively coupled plasma - optical emission spectrometry	wt. %
13	Manganese oxide	MnO	%	Choi, Sarang	ICP-OES, Inductively coupled plasma - optical emission spectrometry	wt. %
14	Phosphorus pentoxide	P2O5	%	Choi, Sarang	ICP-OES, Inductively coupled plasma - optical emission spectrometry	wt. %
15	Loss on ignition	LOI	%	Choi, Sarang		wt. %
16	Total	Total	%	Choi, Sarang		wt. %
17	Iron 2+ oxidation state	OS FeO		Choi, Sarang
18	Iron 3+ oxidation state	OS Fe2O3		Choi, Sarang
19	Iron 3+/Iron total	Fe3+/Fetotal		Choi, Sarang
20	Magnetite	Fe3O4	%	Choi, Sarang		wt. %, iron partitioning between magnetite and silicate minerals
21	Ratio	Ratio		Choi, Sarang		bulk rock Fesilicate/Fetotal; iron partitioning between magnetite and silicate minerals
22	Ratio	Ratio		Choi, Sarang		bulk rock silicate Fe3+/Fetotal; iron partitioning between magnetite and silicate minerals

License:

Creative Commons Attribution 4.0 International (CC-BY-4.0) (License comes into effect after moratorium ends)

Status:

Curation Level: Enhanced curation (CurationLevelC)

Size:

280 data points

Data

Download dataset as tab-delimited text — use the following character encoding:

1 Event	3 Lithology	4 Sample no	5 SiO2 [%] (wt. %)	6 Al2O3 [%] (wt. %)	7 Fe2O3 [%] (wt. %, total)	8 TiO2 [%] (wt. %)	9 MgO [%] (wt. %)	10 CaO [%] (wt. %)	11 Na2O [%] (wt. %)	12 K2O [%] (wt. %)	13 MnO [%] (wt. %)	14 P2O5 [%] (wt. %)	15 LOI [%] (wt. %)	16 Total [%] (wt. %)	17 OS FeO	18 OS Fe2O3	19 Fe3+/Fetotal	20 Fe3O4 [%] (wt. %, iron partitioning betw...)	21 Ratio (bulk rock Fesilicate/Fetotal;...)	22 Ratio (bulk rock silicate Fe3+/Fetot...)
RD1912_DREG	Serpentinite	RD1912-04	40.18	0.88	7.63	0.01	38.41	0.06	0.09	0.01	0.08	<0.01	12.76	99.81	2.7	4.63	0.61	2.75	0.63	0.57
RD1912_DREG	Serpentinite	RD1912-12	40.80	1.09	8.12	0.02	37.49	0.40	0.08	0.02	0.09	<0.01	11.95	99.68	3.3	4.45	0.55	3.10	0.61	0.47
RD1912_DREG	Serpentinite	RD1912-13	38.23	1.15	7.76	0.02	37.71	0.77	0.09	0.01	0.09	<0.01	12.17	97.67	3.1	4.32	0.56	3.58	0.52	0.46
RD1912_DREG	Serpentinite	RD1912-16	38.79	1.69	8.14	0.03	37.16	0.29	0.10	0.04	0.10	<0.01	13.77	99.81	2.7	5.14	0.63	3.30	0.58	0.61
RD1913_DREG	Serpentinite	RD1913-02	41.51	1.61	7.49	0.04	37.00	1.19	0.19	0.04	0.09	<0.01	10.96	99.80	2.9	4.27	0.57	2.82	0.61	0.51
RD2208_DREG	Serpentinite	RD2208-10	38.64	0.92	7.39	0.01	39.85	0.09	0.08	0.01	0.09	0.03	13.64	100.80	1.5	5.72	0.77	4.94	0.31	1.00
RD2208_DREG	Serpentinite	RD2208-11	40.54	1.56	7.04	0.03	37.14	0.72	0.15	0.03	0.08	0.02	11.71	99.01	3.4	3.26	0.46	2.65	0.61	0.33
RD2208_DREG	Serpentinite	RD2208-39	38.25	0.76	7.74	0.02	38.95	0.04	0.12	0.01	0.06	0.04	14.38	100.40	1.5	6.07	0.78	4.31	0.42	0.95
RD1913_DREG	Talc-serpentinite	RD1913-01	44.67	0.77	7.21	0.01	35.79	0.22	0.11	0.02	0.08	<0.01	11.06	99.58	3.2	3.65	0.51	0.88	0.87	0.48
RD2208_DREG	Talc-rich metasomatite	RD2208-04	57.25	1.38	6.28	0.03	26.31	2.17	0.22	0.02	0.06	0.02	5.25	98.99	4.7	1.06	0.17	0.02	1.00	0.17
RD2208_DREG	Talc-rich metasomatite	RD2208-12	54.34	2.41	7.31	0.04	28.50	2.23	0.24	0.02	0.08	<0.01	5.79	101.00	5.5	1.20	0.16	0.02	1.00	0.16
RD2208_DREG	Talc-rich metasomatite	RD2208-13	57.89	1.39	5.38	0.02	28.48	0.57	0.22	0.02	0.05	0.02	5.81	99.86	2.6	2.49	0.46	0.64	0.88	0.43
RD2208_DREG	Talc-rich metasomatite	RD2208-38	57.17	1.65	6.87	0.02	26.89	1.06	0.22	0.02	0.06	0.02	5.86	99.85	4.7	1.65	0.24	0.05	0.99	0.24
RD2208_DREG	Talc-rich metasomatite	RD2208-43	57.01	1.71	7.24	0.03	26.58	0.53	0.22	0.02	0.06	0.03	5.74	99.18	5.6	1.02	0.14	0.16	0.98	0.13