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遼西的下白堊統(tǒng)包括下部沙海組及上部阜新組。沙海組可分為三段，下段為砂礫巖及礫巖；中段為含煤段，由泥巖、砂巖及煤層組成；上段為泥巖。含煤段共含七個煤層組，一般3～4層可采。阜新組由砂礫巖、砂巖、粉砂巖、泥巖和煤層組成，含六個煤層組，總厚可為10～80m。除阜新盆地外，鐵法、元寶山、平莊等盆地阜新組含煤性也很好。遼西和冀北一帶發(fā)育一個特殊的生物群落，即著名的熱河生物群，其早期屬晚侏羅世，代表一個火山活動期；晚期屬早白堊世，是一個成煤期。早白堊世含煤地層中的植物化石為魯福德蕨-類金粉蕨組合(Ruffoudia-Onychiopsis),動物化石則以東方葉肢介(Eosestheria)及擬蜉蝣(Ephemeropsis)為代表，魚類中的Kunrulania已較狼鰭魚進化。這一生物群面貌完全可以和扎賚諾爾群、霍林河群及巴彥花群對比，時代為早白堊世早期或尼歐克姆世。上一頁 [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] [23] [24] [25] [26] [27] [28] [29] [30] [31] [32] [33] [34] [35] [36] [37] [38] [39] [40] [41] [42] [43] [44] [45] [46] [47] [48] [49] [50] [51] [52] [53] [54] [55] [56] [57] [58] [59] [60] [61] [62] [63] [64] [65] [66] [67] [68] [69] [70] [71] [72] [73] [74] 下一頁 |
