Kalewa Section, Sample 23 (Eocene of Myanmar)

Where: Sagaing, Myanmar (23.2° N, 94.3° E: paleocoordinates 14.7° N, 94.2° E)

• coordinate stated in text

• small collection-level geographic resolution

When: Yaw Formation, Late/Upper Eocene (37.2 - 33.9 Ma)

• "U–Pb dating of a tuff layer (Licht et al. 2019), magnetostratigraphy, U–Pb apatite dating and apatite fission track dating (Westerweel et al., 2020) provide an age of c. 38–37 Ma, which is also supported by the palynological evidence discussed below and in Huang et al. 2020, Huang et al. 2018." (Huang et al. 2023)

• bed-level stratigraphic resolution

Environment/lithology: fluvial; lithified sandstone and mudstone

Size class: microfossils

Collection methods: chemical

• "Two palynological processing methods were performed to ensure maximum recovery. One set of samples was processed for quantitative analysis. The processing was as follows: 1.3 g of sample was boiled in 10% sodium pyrophosphate, and then treated with 10% HCl, and sieved with 5 μm and 212 μm meshes. The sample was then heated in acetolysis mixture to 100 °C. Bromoform-treatment was applied to separate any remaining inorganic fraction to produce residue. A second set of selected samples was processed mainly for microphotography. The processing method was as follows: 30 g of washed and dried sample was treated with 10% HCl and 40% HF. Then a heavy liquid separation was used to separate the organic and remaining inorganic fractions. All resulting residues were mounted on a slide in glycerin and sealed with paraffin for light microscope (LM) observation. Residues were further used for analysis with LM and scanning electron microscopy (SEM) at the Department of Palaeontology (DoP), University of Vienna, Austria. Details on the two methods were presented in Huang et al. (2020)." (Huang et al. 2023)

Primary reference: H. Huang, R. J. Morley, A. Licht, G. Dupont-Nivet, D. Pérez-Pinedo, J. Westerweel, Z. Win, D. Wa Aung, E. Budi Lelono, G. N. Aleksandrova, R. K. Saxena and C. Hoorn. 2023. A proto-monsoonal climate in the late Eocene of Southeast Asia: evidence from a sedimentary record in central Myanmar. Geoscience Frontiers 14(1):101457 [B. Allen/B. Allen]more details

Purpose of describing collection: paleoecologic analysis

PaleoDB collection 227671: authorized by Bethany Allen, entered by Bethany Allen on 26.10.2022

Creative Commons license: CC BY (attribution)

Taxonomic list

unclassified
  -
 Anthocerotophyta -
Saxosporis sp. Krutzsch 1963 hornwort
Lycopodiopsida
 Selaginellales - Selaginellaceae
? Selaginella sp. Beauvois 1804 spikemoss
Polypodiopsida
 Polypodiales - Polypodiidae
Pterisisporites sp. Sung and Zheng
  - Polypodiaceae
Verrucatosporites sp. Pflug and Thomson 1953
Verrucatosporites usmensis Germeraad et al. 1968
Laevigatosporites sp. Ibrahim 1933
Pteridopsida
  -
Deltoidospora sp. Miner 1935
Angiospermae
 Fabales - Fabaceae
Margocolporites sp. Ramanajuan 1966 legume
 Malpighiales - Calophyllaceae
Calophyllumpollenites sp. Sah and Kar 1974
 Malpighiales - Euphorbiaceae
Euphorbiaceae indet. Jussieu 1789 spurge
 Fagales - Fagaceae
 Fagales - Casuarinaceae
Casuarinidites cainozoicus Cookson and Pike 1954
 Malvales - Malvaceae
 Sapindales - Sapindaceae
Striasyncolpites sp. Mildenhall and Pocknall soapberry
 Sapindales - Anacardiaceae
Campnosperma sp. Thwaites 1854 cashew
Dicotyledoneae
 Myrtales -
 Ericales - Sapotaceae
Sapotaceoidaepollenites sp. Potonié et al. 1950
 Ericales -
Angiospermae
  -
Tetracolpites sp. Srivastava 1967
 Mesangiosperms - Arecaceae
 Mesangiosperms - Araceae
Proxapertites sp. Van der Hammen 1956
Proxapertites operculatus Van der Hammen 1956
 Gentianales - Apocynaceae
Cricotriporites sp. Leidelmeyer 1966 dogbane
 Gentianales - Rubiaceae
Rubiaceae indet. Jussieu 1789 coffee
Acrostichum
  -
Acrostichum sp. Linnaeus 1753