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東南區(qū)三疊紀(jì)含煤地層以江西萍鄉(xiāng)為代表，稱(chēng)安源組�？梢苑譃槿齻�(gè)巖性段，下段稱(chēng)紫家沖段，為主要含煤段，底部礫巖或砂礫巖，向上以砂巖、粉砂巖為主，一般含煤7～8層；中段稱(chēng)三家沖段，以黑色泥巖為主，夾粉砂巖，富含海相瓣腮類(lèi)化石；上段稱(chēng)三丘田段，以石英砂巖及粉砂巖為主，夾數(shù)層砂礫巖，含局部可采煤1～4層。安源組總厚約700m，植物化石仍以中華叉羽葉及粗脈大網(wǎng)羽葉為主，瓣腮類(lèi)化石豐富，以類(lèi)貝莢蛤、江西蛤、偏頂蛤?yàn)榇恚瑸橹Z利至瑞替期。安源組下伏地層各地均不一致，代表印支運(yùn)動(dòng)的不整合面，上覆地層一般為中粗粒長(zhǎng)石石英砂巖，江西稱(chēng)門(mén)口山組，屬早侏羅世里阿斯期。廣東的晚三疊世含煤地層和萍鄉(xiāng)相似，稱(chēng)艮口組，自下而上可分為紅衛(wèi)坑段、小水段和頭木沖段；湘南的相當(dāng)?shù)貙幼韵露蠟槌鎏扣舛魏蜅蠲粉舛�；閩西南則分別為大坑段和文賓山段。晚三疊世至早侏羅世可能有兩次區(qū)域性地層超覆，第一次在三丘田段或焦坑段前，造成贛東及閩北等地缺少紫家沖段或大坑段；第二次在三疊紀(jì)—侏羅紀(jì)間，湘東等地可見(jiàn)門(mén)口山組超覆在古生代地層之上。上一頁(yè) [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(yè) |
