Raw data of manuscript Formation of authigenic titania during the alteration of volcanic glasses in modern deep-sea environments
Description
Our study provides novel findings on the occurrence and growth mechanism of authigenic titania in the volcanic glasses collected from Line and Marshall seamounts by using multiple microanalytical methods. Both specimens primarily consist of mixed-layer illite/smectite, phillipsite, and carbonate-bearing fluorapatite, revealing that the volcanic glasses underwent palagonization processes. Scanning electron micrograph reveal numerous spherical Ti-rich shells with thickness of 450–1000 nm, enveloping spherical smectite aggregates with diameters of dozens to hundreds of microns. Further analysis using transmission electron microscopy confirm the presence of authigenic Fe-bearing titania particles in these Ti-rich shells. Additionally, abundant titania nanoparticles, with aggregate sizes of 4–32 nm, were observed in the pore spaces of the smectite aggregates. Brookite is the dominant titania phase in both the titania shells and the smectite pores, with rutile and anatase occasionally present in the titania shells. These observations suggest the continuous mineral phase evolution during the growth of titania particles, possibly influenced by the heterogeneity of Ti concentration and size-dependent thermodynamic stability of titania. The growth of the titania particles could be largely attributed to crystallization by particle attachment as evidenced by the abundant lattice alignment of titania nanoparticles. The occurrence and distribution of titania exhibited a negative correlation with the alteration degree of volcanic glass, suggesting a short-distance migration of Ti with palagonization processes. Meanwhile, the crystallization of titania and mixed-layer illite/smectite along with the alteration of volcanic materials indicate potential Ti isotopic fractionation. These findings provide solid evidence for the mobilization of Ti, which is crucial for understanding the marine geochemical behaviors and isotopic fractionation of Ti.