Miocene phytolith and diatom dataset from 10.3Myo diatomite formation, Fernley, Nevada, USA

Phytoliths are opal silica particles formed within plant tissues. Diatoms are aquatic, single-celled photosynthetic algae with silica skeletons. Phytolith and diatom morphotypes vary depending on local environmental and climatic conditions and because their silicate structures preserve well, the study of phytolith and diatom morphotypes can be used to better understand paleoclimatic and paleoenvironmental dynamics and changes. This article presents original data from an 820cm-deep stratigraphy excavated at the Hazen diatomite deposits, a high-elevation desert paleolake in the Fernley District, Northern Nevada, USA. The site has been studied for an assemblage of fossilized threespine stickleback, Gasterosteus doryssus, that reveal adaptive evolution. For this study, a total of 157 samples were extracted at 20 cm intervals covering approximately 24,500 years. After extraction, the samples were mounted on slides and viewed under 400-1000x light microscopy, enabling classification of 14 phytolith and 45 diatom morphotypes. Our data support paleoenvironmental reconstructions of the Hazen Miocene paleolake.

a b s t r a c t Phytoliths are opal silica particles formed within plant tissues.Diatoms are aquatic, single-celled photosynthetic algae with silica skeletons.Phytolith and diatom morphotypes vary depending on local environmental and climatic conditions and because their silicate structures preserve well, the study of phytolith and diatom morphotypes can be used to better understand paleoclimatic and paleoenvironmental dynamics and changes.This article presents original data from an 820cm-deep stratigraphy excavated at the Hazen diatomite deposits, a high-elevation desert paleolake in the Fernley District, Northern Nevada, USA.The site has been studied for an assemblage of fossilized threespine stickleback, Gasterosteus doryssus , that reveal adaptive evolution.For this study, a total of 157 samples were extracted at 20 cm intervals covering approximately 24,500 years.After extraction, the samples were mounted on slides and viewed under 40 0-10 0 0x light microscopy, enabling classification of 14 phytolith and 45 diatom morphotypes.Our data support paleoenvironmental reconstructions of the Hazen Miocene paleolake.

Value of the Data
• The fossil phytolith and diatom data can be used to reconstruct palaeoecological histories of local and regional vegetation, volcanic and fire activity, and other environmental variables.• Explainable changes in abundance and composition of ancient microfossil communities may help predict how modern life might respond to similar environmental change.• The paleoenvironment reconstruction may help explain observed adaptive evolution by the threespine stickleback fish ( Gasterosteus doryssus ) collected from the same stratigraphic sections.

Objective
This article presents original phytolith and diatom data from a currently high-elevation desert paleolake in Northern Nevada (Fernley District, USA) comprised of Miocene diatomite [1 , 2] .The samples were originally collected to study the fossilized threespine stickleback, Gasterosteus doryssus .157 samples spanning approximately 24,500 years of stratigraphical deposition were extracted following a published protocol [3] to identify diatom and phytolith morphotypes.The objective of this study was to offer a new dataset for future study of paleoenvironmental and paleoclimatic contexts of paleolakes from the Hazen Miocene.Micrographs and morphological and identification details of phytolith and diatom morphotypes can be found in Fig. 1 and Table 1 .[5] Tetracyclus spp.

Experimental design
The 'Bot-Meps' Protocol [3] was followed for the sampling and slide preparation processes used to develop the presented dataset.Here is a brief summary of the major steps: (1) A 5mm wide chisel was used to outline a 1 cm × 1 cm section as a sampling region.This was done in a fume hood onto a protective surface.(2) The same chisel was used to separate the 1 × 1 cm sample from the rock matrix, at depths ranging from 2-4 cm, depending on the thickness of the specimen.(3) The sample was placed in 1.5 mL Eppendorf tubes and ground to a fine powder using a needle tool.Between each sample the tools used were cleaned to prevent crosscontamination.
(4) Resulting powder was mounted onto glass slides with medium viscosity mounting oil and sealed.(5) Slides were analyzed using a brightfield optical microscope with 40 and 100 x objective le5ses and 10 x eye lenses.Microphotographs were achieved using a Meiji Techno HD1500T microscope camera.

Methods
The samples were extracted and prepared following the 'Bot-MEPS' Protocol [3] , though because our samples were free of carbonates and organic residues (Cerasoni, unpublished data) we did not follow the steps to remove those residues, nor did we need the heavy liquid flotation separation technique.The resulting ground samples were analyzed by brightfield optical microscopy at 40x and 100x magnification.The identification of each morphotype was carried out by matching with a high degree of confidence size, shape, surface texture and unique features to previously published databases and standards [11][12][13][14][15][16][17][18] .All microfossils that did not match any known published diatom or phytolith morphotype were recorded as unidentified, but still presented here.

Fig. 2 .
Fig. 2. Location of the study area (c) within the state of Nevada (b) in the United States of America (a).
© 2023 The Author(s).Published by Elsevier Inc.This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ )

Table 1 (
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