Abstract: | In the northern part of South China Sea, including Tonkin Gulf, Hainan lsland,
Leizhon Peninsula and some basin of Guangdong Province, Paleogene deposits are
composed of three formations: the Weizhon, the Liushagang and the Changliu formations arranged in descending order. The paper on the palynoflora of the Weizhon
Formation (early and middle Oligocene) is in press2]. This paper deals only with the
palynoflora of the Liushagang Formation, with may be divided into four main stages:
The first stage is represented by Monocolpollenites tranquillus and Crassoretitriletes sp., assigned to early Eocene The second stage is characterized by Salixipollenites,
Momipites triletipollenites and Operculumpollis. Its age is middle Eocene. The third
stage is dominated by some species of Quercoidites and Ulmipollenites and also
characterized by the presence of Platycaryapollenites and Prominangularia dogyingensis, This sporo-pollen assemblage suggests a late Eocene in age. The fouth stage is
marked by profusion of some alga of brockish water, such as Rugasphera corrugia,
Granodiscus gronulatus and some pollen types of Liquidambarpollenites minutus,
Multiporopollenites puctatus and Tricolporopollenites minutus. The age of the last
stage is assigned to early oliocene.
In generaly, the palynoflora of the Liushagang Formation is quite different from
that of the Weizhou Formation. The main types of spores and pollen are common
with those found in Europe and North America of the same age, while the Weizhou
Formation has many elements common both in this region and Borneo.
During Eocene and early Oligocene this area was of continental phase with
brackish basins. At the beginning the climate was rather moist and hot, but then itbecame moist and warmtemperate. |