Late Pleistocene plant macro-fossils from the Gokarna Formation of the Kathmandu Valley, Central Nepal

Abstract

The Kathmandu Valley offers the best archive to study the Late Pleistocene climate in Nepal. The Gokarna Formation, constituting the middle part of the sedimentary sequence of the Kathmandu Valley comprises alternating layers of carbonaceous clay, silt, massive to parallel and large scale cross stratified, fine to coarse grained sands and occasional gravel layers, deposited at fluvio-deltaic and lacustrine environment. The organic rich layers of clay, silt, silty-sand and micaceous fine sand consists of abundant plant macro-fossils (fruit, seed and leaves). Plant macrofossils assemblage from the Gokarna Formation (thickness 28.5 m, Dhapasi section) in the northern part of the valley consists of 56 taxa from 35 families. Depending upon the available plant, seven macrofossil assemblages, DS-I to DS-VII in ascending order were established. The common tree and shrubs discovered from this section were Eurya, Ficus, Carpinus, Quercus, Alnus, Rubus, Pyracantha, Zizyphus, Carpinus, Boehmeria etc. Carex, Scirpus triqueter, Scirpus, Polygonum, Euphorbia, Oxalis, Mosla, Viola etc. were the common herbaceous taxa. The constant occurrence of subtropical and warm temperate taxa including Eurya, Ficus, Pyracantha and Zizyphus indicated that subtropical and warm temperate climate continued during the deposition of those macrofossil assemblages. However change in the constituents of those taxa and occurrence of taxa indicating cooler climatic condition like conifers and Betula may indicate minor fluctuation of climate during the deposition of the Gokarna Formation. doi: 10.3126/bdg.v12i0.2252 Bulletin of the Department of Geology, Vol. 12, 2009, pp. 75-88

An early Oligocene fossil acorn, associated leaves and pollen of the ring‐cupped oaks (Quercus subg. Cyclobalanopsis) from Maoming Basin, South China

“…The earliest reliable Quercus fossil records are leaves, fruits, or woods from the middle Eocene floras of Nevada and Oregon in North America (MacGinitie, ; Bones, ; Manchester, ; 1994) and the leaf with cuticles recovered from the Aschersleben flora of Germany in Europe (Kvaček & Walther, ). Fossil records of the genus are also abundant from the Oligocene onward (Axelrod, , , , 1995, 1998, 2000; Guo, , ; WGCPC, ; Zhang, ; Wolfe & Tanai, ; Takhtajan, ; Meyer & Manchester, ; Palamarev & Tsenov, ; Bhandari et al, ; Jia et al, , ; Hably, ; Xing et al, ; Xu et al, ).…”

“…The majority of the fossil records of subg. Cyclobalanopsis are leaves; fossil acorns assignable to this subgenus are rare, only being reported from the middle Eocene of North America, the late Eocene of Japan, the Miocene to Pliocene of southeast and southwest of China, and the late Pleistocene of Nepal (Huzioka & Takahashi, 1970; Zhang ; Li & Guo, ; Manchester, ; Tao, ; Bhandari et al, ; Jia et al, ). The acorn discussed here is the first Oligocene fruit record worldwide.…”

“…Early Oligocene ring-cupped oaks from South China in North America (MacGinitie, 1941;Bones, 1979;Manchester, 1983;1994) and the leaf with cuticles recovered from the Aschersleben flora of Germany in Europe (Kva cek & Walther, 1989). Fossil records of the genus are also abundant from the Oligocene onward (Axelrod, 1956(Axelrod, , 1966(Axelrod, , 1992(Axelrod, , 1995(Axelrod, , 1998(Axelrod, , 2000Guo, 1978Guo, , 2011WGCPC, 1978;Zhang, 1978;Wolfe & Tanai, 1980;Takhtajan, 1982;Meyer & Manchester, 1997;Palamarev & Tsenov, 2004;Bhandari et al, 2009;Jia et al, 2009Jia et al, , 2015Hably, 2013;Xing et al, 2013;Xu et al, 2016).…”

Upper Pliocene to Lower Pleistocene Plant Microfossils from The Basal Part of the Lukundol Formation (Southern Kathmandu Valley) and Their Climatic Implications

“…Later, Paudel and Sakai (2008) stratigraphically divided southern Kathmandu valley sediments into 6 units such as Tarebhir, Lukundol, Sunakothi, Itaiti formations, Terrace Gravel Deposit and Kalimati Formation from older to younger. Many researchers have done the palynological and macrofossil study in the northern and southern parts of the Kathmandu valley sediments (Kral and Havinga 1979;Mittre and Sharma 1984;Yoshida and Igarashi 1984;Fuji and Sakai 2002;Paudayal and Ferguson 2004;Paudayal 2005Paudayal , 2006Paudayal , 2011aPaudayal , 2011bBhandari et al 2009Bhandari et al , 2010. The first palynological study from the Lukundol Formation was done by Yoshida and Igarashi (1984) and Igarashi et al (1988) and explored the great potential for using plant microfossils to study the past climate from this area.…”

Vegetation and Climate Around 780 Kyrs BP in Northern Kathmandu Valley, Central Nepal

“…The plant microfossil and other plant remains obtained from the basin sediments have been studied by different researchers (Karl and Havinga 1979;Yoshida and Igarashi 1984;Mittre and Sharma 1984;Igarashi et al 1988;Nakagawa et al 1996;Ooi 2001;Sakai 2001, 2002;Paudayal and Ferguson 2004;Paudayal 2005Paudayal , 2006Paudayal , 2011aPaudayal , 2011bBhandari and Paudayal 2007;Bhandari et al 2009Bhandari et al , 2010Bhandari et al , 2011aBhandari et al , 2011bBhandari et al , 2016Khatri 2015). The Dharmasthali Formation is exposed in the northern part of the Kathmandu Basin.…”