Stable isotope geochemistry of Gwebin mammalian fauna with implications for late Neogene paleoenvironmental changes in central Myanmar. (15th September 2021)

• Record Type: Journal Article
• Authors: Zin-Maung-Maung-Thein, ; Takai, Masanaru; Nishioka, Yuichiro; Wynn, Jonathan; Uno, Hikaru; Thaung-Htike, ; Egi, Naoko; Tsubamoto, Takehisa; Maung-Maung,
• Is Part Of: Journal of Asian earth sciences. Volume 218(2021)
• Publication Date: 2021-09-15
• Subjects: Irrawaddy sediments -- Myanmar -- Neogene -- Paleoenvironment -- Paleogeography -- Stable isotopes; Earth sciences -- Asia -- Periodicals; Sciences de la terre -- Asie -- Périodiques; Earth sciences; Asia; Periodicals; 555.05
• DOI: 10.1016/j.jseaes.2021.104884
• Languages: English
• ISSNs: 1367-9120

Abstract

Highlights: C3 plants resources were dominant in the late Neogene of central Myanmar. Floral transition at the Mio-Pliocene boundary had a limited impact on the SE Asia. Unique paleogeographical condition of central Myanmar served as a refugium in the late Neogene. Onset of aridification in Myanmar is related to Pleistocene sea level changes in SE Asia. Abstract: To explore the paleoenvironmental changes in SE Asia during the late Neogene, we examined the stable carbon and oxygen isotope compositions of tooth enamel from mammals of the late Pliocene/earliest Pleistocene Gwebin area in central Myanmar and compared the results with those of the latest Miocene Chaingzauk mammals in Myanmar. The stable carbon isotope values (δ 13 C) of Gwebin mammals indicate that they inhabited mosaic environment ranging from woodland to grassland. The relative abundance of C3 -browsing versus C4 -grazing bovids as well as other C3 -consuming anthracotheriids, porcupine, rhinoceroses, suids, and stegodontids suggest the dominance of wooded environment. In central Myanmar, it is assumed that floral transition from C3 to C4 plants has occurred since the latest Miocene to Early Pliocene relating to the Himalayan Orogeny. However, stable isotope data at present indicate that paleoenvironment of central Myanmar did not change considerably in the Pliocene and served as a refugium for several forest/woodland dwellers at least until the early Pleistocene. The development of the proto-Ayeyarwady and proto-Chindwin drainage systems in the late Neogene of Myanmar induced the riparian environment, probably buffering against the rain shadow effect of the Indo-Myanmar Ranges. The onset of the present day aridification in central Myanmar is probably related to the Middle to Late Pleistocene sea-level changes in SE Asian region, which have had a major impact on climate, vegetation and megafauna of SE Asia.