7) 中國重要的第三紀(jì)含煤盆地主要分布于兩個地區(qū)，又分屬于不同時期。即東北區(qū)早第三紀(jì)含煤地層及云南區(qū)晚第三紀(jì)含煤地層。東北、華北區(qū)早第三紀(jì)含煤盆地共有40余個，最著名的當(dāng)屬遼寧撫順盆地，含煤地層稱撫順群，厚880～1 050m，自下而上分為老虎臺組、栗子溝組、古城子組、計軍屯組、西露天組和耿家街組。下部老虎臺組、栗子溝組以玄武巖、凝灰?guī)r為主，夾砂礫巖、泥巖及不穩(wěn)定煤層；中部古城子組、計軍屯組為含主要煤層及厚層油頁巖層位；上部西露天組、耿家街組夾泥灰?guī)r，不含煤。撫順群主煤層可厚達(dá)120m，油頁巖為50～190m，系巨厚礦層。據(jù)植物及孢粉化石，下部屬古新世，中部及上部屬始新世。此外，梅河盆地的梅河組、沈北盆地的楊連屯組均可與之相當(dāng)。
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