Data from: Rapid transformation of biogenic silica to authigenic clay: Mechanisms and geochemical constraints

Data files

Jun 30, 2026 version files 49.92 KB

adt3374_Supplementary_data_S1.csv

12.07 KB
adt3374_Supplementary_data_S1.xlsx

30.95 KB
README.md

6.90 KB

Abstract

Authigenic clay formation during early diagenesis of marine sediments, termed “reverse weathering”, is an important process for regulating ocean pH, seawater chemistry, and atmospheric CO2 over geologic time scales. Although the importance of reverse weathering has been increasingly recognized, the rates and mechanisms remain poorly constrained. This study investigated the mechanisms, kinetics, and mineral products derived from diatom biogenic silica. We show the formation of Fe(II)-smectite and mica in 40 days, the most rapid process and first specific mineral phases reported to date. Unraveling the kinetics and mechanisms of secondary phase formation suggests an up to one order of magnitude upward revision of potential reverse weathering rates in marine sediments. This implies that reverse weathering is far more responsive to changes in ocean chemistry and climate state than previously envisioned, suggesting its potentially more significant role in regulating carbon and alkalinity cycles in the modern ocean and through Earth’s history.

Supplementary data S1: compiled solution phase data and EDX data

Brief summary of the data and file structure

File: adt3374_Supplementary_data_S1.xlsx
This compilation contains time-course solution phase data for all treatment groups and elemental stochiometric ratios for authigenic clay phases, organized by figures and tables by Excel Tabs as below:

Tab 1. Figure 4. Time evolution of dissolved Fe(II) and apparent dissolved Si in the presence of bSi and 150 μM background dissolved Si(OH)4
Tab 2. Figure S4. Time evolution of dissolved Fe(II) and Si in the presence of 150 μM dissolved Si(OH)4 only
Tab 3. Figure S5. Dissolved Al from Al(OH)3 treatments with or without Fe(OH)3 and bSi
Tab 4. Table S2. Elemental ratios in the authigenic mineral phase

The experimental treatment groups and sample label are detailed as below:

Treatment group	Dissolved Si(OH)4 (µM)	Dissolved Fe(II) (µM)	bSi	Fe(OH)3	Al(OH)3	Sample label
I (with bSi)	150	0	+			0Fe(II)+bSi
	150	0	+	+		0Fe(II)+bSi+Fe
	150	0	+		+	0Fe(II)+bSi+Al
	150	0	+	+	+	0Fe(II)+bSi+FeAl
	150	100	+			100Fe(II)+bSi
	150	100	+	+		100Fe(II)+bSi+Fe
	150	100	+		+	100Fe(II)+bSi+Al
	150	100	+	+	+	100Fe(II)+bSi+FeAl
	150	1000	+			1000Fe(II)+bSi
	150	1000	+	+		1000Fe(II)+bSi+Fe
	150	1000	+		+	1000Fe(II)+bSi+Al
	150	1000	+	+	+	1000Fe(II)+bSi+FeAl

Treatment group	Dissolved Si(OH)4 (µM)	Dissolved Fe(II) (µM)	Fe(OH)3	Al(OH)3	Sample label
II (without bSi)	150	0			0Fe(II)+dSi
	150	0	+		0Fe(II)+dSi+Fe
	150	0		+	0Fe(II)+dSi+Al
	150	0	+	+	0Fe(II)+dSi+FeAl
	150	100			100Fe(II)+dSi
	150	100	+		100Fe(II)+dSi+Fe
	150	100		+	100Fe(II)+dSi+Al
	150	100	+	+	100Fe(II)+dSi+FeAl
	150	1000			1000Fe(II)+dSi
	150	1000	+		1000Fe(II)+dSi+Fe
	150	1000		+	1000Fe(II)+dSi+Al
	150	1000	+	+	1000Fe(II)+dSi+FeAl
III (without bSi)	150	100		30 µM dissolved Al3+	Dissolved only

Description of the data and file structure

Detailed Description of each figure and table for the above organized data:
Tab 1. Aqueous data for Figure 4 in the main text.
Figure caption: Time evolution of dissolved Fe(II) and apparent dissolved Si in the presence of bSi and 150 μM initial dissolved Si(OH)4. Top (A, B), middle (C, D), and bottom panels (E, F) are treatments with 0 μM, 100 Fe(II), or 1000 μM Fe(II). The prefixes of 0Fe(II), 100Fe(II), and 1000Fe(II) in sample labels are omitted for the top, middle and bottom panels for succinctness. Error bars represent standard deviation of duplicate treatment.

Note: All data plotted in the figure are provided in this table. Empty cells are intentionally retained to maintain consistent formatting across treatment panels (0 µM, 100 µM, and 1000 µM Fe(II)) as shown in the figure.

Tab 2. Aqueous data for Figure S4 in the supplementary material.
Figure caption: Time evolution of dissolved Fe(II) and Si in the presence of 150 μM dissolved Si(OH)4 only. Top (A, B), middle (C, D), and bottom panels (E, F) are treatments with 0 μM, 100 Fe(II), or 1000 μM Fe(II). The prefixes of 0Fe(II), 100Fe(II), and 1000Fe(II) in sample labels are omitted for the top, middle and bottom panels for succinctness. Error bars represent standard deviation of duplicate treatments.

Tab 3. Aqueous data for Figure S5 in the supplementary material.
Figure caption: Dissolved Al from Al(OH)3 in treatments with or without Fe(OH)3 and bSi. (A) 0 μM Fe(II) treatments; (B) 100 μM Fe(II) treatments; (C) 1000 μM Fe(II) treatments.

Note: “n/a” indicates that the standard deviation was not available because the measured concentration was zero (i.e., not detected).

Tab 4. Solid phase data for Table S2
Table caption: Elemental ratios of authigenic phases.

File: adt3374_Supplementary_data_S1.csv
A comma-separated values version of adt3374_Supplementary_data_S1.xlsx. All info is in one sheet.