哈尔滨地区第四纪孢粉分析及其在地质学和植物学上的意义

本文依据哈尔滨地区不同地貌单元内三个钻孔和三个自然剖面孢粉分析资料,结合古地磁测试,热释光和放射性碳素年令测定,进行钻孔和剖面间对比,初步建立起哈尔滨地区第四纪孢粉组合特征,进而讨论了哈尔滨地区第四纪以来植物群发展和气候变化。

PALYNOFLORA OF THE QUATERNARY FROM THE HARBIN HEILONGJIANG PROVINCE AND ITS SIGNIFICANCE IN GEOLOGY AND BOTANY

In recent years, we carried out pollen analysis on some se-diments of the pleistocene and Holocene from the vicinity of Harbin, Heilonjiang province. The samples were collected in the field by geological worker of the Hydrology team no. 2, Heilongjiang. This paper is on the basis of characteristics of sporo-pollen assemblages from 3 boreholes and 3 geological sections of Har-bin and further interpretes paleovegetation, paleogeogaphy and paleoclimate, It is significantion more or less to use pollen an-alysis in Hydrogeology. Acconding to the palynology stratigraphy magnetostigraphic studies, thermolunescent date and radiocarbon dating some conclusions can be drown:1. The Cretaceous flora is mainly composed of Cyatheaceae, Lygodiaceae, Schiaceae, Cycadaceae and Taxodiaceae, podocarpus, Cedrus of Conifere, The climate was hot and wet. The vegetation shows tropical south subtropical in aspect. The annual tempe-rature was about 14.2℃ higher than that of present. 2. The flora of palaeogene is represented by some warm-temperature and subtropical deciduous forests among which some evengreen trees were in existence. The climate was wet and less hot. The annual temperature was about 10℃ higher-than that of the present. 3. The flora of Neogene is mainly composed of Amentiferae but some subtropical species of Liquidambar, Carya, Fagus etc. are still in existence. the climate was warm and wet. The annual temperature was higher than that of the present. As to late pliocene, The Harbaceous plants such as chenopodiaceae, Com-positae and Gramineae etc, were obviously increase. 4. Quaternary floras:The floras of the glaeial and intergla-cial periods are quite different here. About 31×10⁴-28×10⁴ (Luo jiawopeng formation) years ago herbaceous plants such as Artemisia, Chenopodiaceae, Humulus, Compositae were flourishing in plain of Harbin and mountainous region, in cold-tempera-ture forest consisted of Picea and. Betula. According to the steppe or tundra increasing at that time we think ahout 30×10⁵ B. P. ago or so that time climate was cold and dry. In the past 28×10⁵-25×10⁵ years (Guanjiawopeng formation)deciduous broad-leaved forest consisted of Betula, Corglus thrived under a warm and humid climate. About 25×10⁵-10×10⁵ years ago (correspond to Baitushan formation), the floras were alter-nation of steppe and forest. In the early period of that time the flora was represented by steppe or tundra, climate was cold and dry, then by cold-temperature coniferous-broadleaf forest consisting of Picea, Abies, Betula etc. Meantime the aquaticplants such as Typha, Myriophyllum and Green algae were growing in some shallow stangant ponds lakes or marshes of the vicinity Harbin. The climate was rather humid and warm. In the last part of the period the flora was characterised by deciduous broad-leaved forest consisted of Betula, Quercus, Alnus, Ulmus, Tilia, Juglans, Acer, Corylus with scattered Tsuga and Fagus etc.indicating the existence of a warm temperature climate in the early interglacial period. In the past 10×10⁵-5×10⁵ years (Cor-respondent to Huangshan formation) was very poorly represented only Humulus, Artemisia. Chenopodiaceae. We think at that time the vegetational zone belongs to typical desert and steppe, the climate was very dry. During 40×10⁴-15×10⁴ years B. P. (Har-bin formation) was a cold-temperature steppe consisted of Artemisia, Chenopodium etc. thrived under a cold and wet climate, Meantime lakes and marshes apparently decreased with glacial period of the Quaternary. As to tke sporo-pollen assemblagesin the Guxiangtun formation (15×10⁴-3×10⁴ Yr. B. P.) show there was cold temperate glassland consisted of Artemisia, Che-nopodium, Humulus and Gramineae so we infer that the vicinity Harbin at that time should be one of cold and dry natural environment.