Mineral data (SEM, electron microprobe, Raman spectroscopy) from epithermal hydrothermal alteration of the Miocene Sigri Petrified Forest and host pyroclastic rocks, Western Lesbos, Greece

David J.W. Piper,Nickolas C. Zouros,George Anastasakis,Georgia Pe-Piper,Alexis Imperial

doi:10.1016/j.dib.2019.103987

Abstract

Data available from a detailed mineralogical investigation of the Petrified Forest of Lesbos and its host pyroclastic rocks [1] are summarized and a link is provided to the full data at https://data.mendeley.com/datasets/dxwfd32zms/1. Samples were taken from petrified wood, fresh and devitrified tuffs, and from epithermal veins and epithermally altered tuffs. Backscattered electron (BSE) images were made by scanning electron microscope (SEM) from polished thin sections of 16 samples to show textural relationships between minerals. Minerals were identified by energy dispersive spectroscopy (EDS). Further chemical analysis by electron microprobe (EMP) were made of trace elements in the petrified wood and of Mn-oxide minerals. Polymorphs of silica were investigated by Raman spectroscopy. SEM X-Ray maps were made of selected sites with manganese oxide minerals. In this contribution, the general character of each analyzed sample is summarized and a brief inventory of available data is presented, with specific reference to features in the on-line data. The significance of these data for the origin of the petrification of the wood and the epithermal veining of the host pyroclastic rocks is provided in “Nature of the hydrothermal alteration of the Miocene Sigri Petrified Forest and host pyroclastic rocks, Lesbos, Greece” [1] https://doi.org/10.1016/j.jvolgeores.2018.11.018. The data will be of comparative value to those investigating petrification of wood, devitrification of tuffs, and epithermal Mn-Fe mineralization in other areas.

Highlights

Field collection of samplesRock samples were collected from the Jithra ignimbrite, the sediments underlying the ignimbrite, hydrothermal yellow veins cutting across pyroclastic rocks or tree horizons, and small samples from fossilized trees from the Sigri Petrified Forest (Table 1)
Mineral data (SEM, electron microprobe, Raman spectroscopy) from epithermal hydrothermal alteration of the Miocene Sigri Petrified Forest and host pyroclastic rocks, Western Lesbos, Greece
Value of the data These data on detailed mineralogy of petrified wood samples, devitrified tuffs, and regional epithermal veins are useful for comparison with other areas of similar epithermal mineralogy

Summary

Field collection of samples

Rock samples were collected from the Jithra ignimbrite, the sediments underlying the ignimbrite, hydrothermal yellow veins cutting across pyroclastic rocks or tree horizons, and small samples from fossilized trees from the Sigri Petrified Forest (Table 1). The presence of alteration during field observation, in order to identify hydrothermal mineral assemblages present in these rocks by comparison to unaltered rocks

Sample Preparation

Analytical techniques