(1. 中南大學(xué) 地球科學(xué)與信息物理學(xué)院，長(zhǎng)沙 410083；
2. 中南大學(xué) 有色金屬成礦預(yù)測(cè)教育部重點(diǎn)實(shí)驗(yàn)室，長(zhǎng)沙 410083；
3. 貴州省有色金屬地質(zhì)和核工業(yè)地質(zhì)勘查局，貴陽(yáng) 550005)
摘 要: 對(duì)黔北務(wù)正道地區(qū)鋁土礦進(jìn)行層序地層學(xué)分析有利于認(rèn)識(shí)鋁土礦分布規(guī)律和形成機(jī)理，可有效解指導(dǎo)將來鋁土礦勘探。通過探槽和取心井巖心觀察以及鋁土礦含礦層系樣品分析化驗(yàn)資料分析認(rèn)為，研究區(qū)梁山組鋁土礦含礦層系為海相和陸相環(huán)境沉積，其沉積相類型包括沖積扇、瀉湖、湖泊和沼澤。鋁土礦含礦層系可劃分為3個(gè)Ⅰ型層序界面，識(shí)別出3個(gè)三級(jí)層序。每個(gè)層序下部的綠泥石巖和鋁土巖為海侵體系域沉積，而層序上部的鋁土礦則為湖泊相沉積。從含礦層系到棲霞組底部整體為海平面不斷上升，沉積相類型也由含礦層系的海相和陸相互層過渡為海相碳酸鹽巖沉積。海侵體系域沉積期跨時(shí)較短，易于形成沖積扇和瀉湖等沉積，巖石類型包括綠泥石巖和鋁土巖，而高位體系域跨時(shí)較長(zhǎng)，綠泥石巖、鋁土巖及其風(fēng)化物能夠進(jìn)行充分的沉積分異作用，從而形成鋁土礦，因此，層序格架對(duì)鋁土礦的形成具有控制作用。
關(guān)鍵字: 沉積型鋁土礦；層序地層學(xué)；湖泊相；沉積分異；基準(zhǔn)面
（1. School of Geosciences and Info-physics, Central South University, Changsha 410083, China;
2. Key Laboratory of Nonferrous Metallogentic Prognosis, Ministry of Education,
Central South University, Changsha 410083, China;
3. Non-ferrous Metals and Nuclear Industry Geological Exploration Bureau of Guizhou, Guiyang 550005, China）
Abstract:Bauxite distribution law and formation mechanism can be known by sequence stratigraphy analyses of bauxite in Wuzhengdao area, North Guizhou, which can guide exploration of bauxite ore. Based on observation of exploratory trench, cores well and results of sample test, it can be gotten that the main facies of bauxite are marine and continental sedimentary environment, including alluvial fan, lagoon, lake and marsh. Three sequence boundaries of type Ⅰcan be identified, and three sequences can be divided. Chlorite rock and bauxite rock under every sequence deposit in transgressive system tract and bauxite ore upper every sequence deposits in lake. The marine level rises from ore-bearing layer to bottom of Qixia formation (P2q) on the whole, and the facies change from marine and continental facies to marine facies correspondingly. The time is short during deposit of transgressive system tract, and alluvial fan and lagoon develop well. The rock types of transgressive system tract include chlorite and bauxite rock. The time is long during deposit of highstand system tract, and the sedimentary differentiation of chlorite, bauxite rock and its weathered material is carried out fully, which result in forming bauxite ore. So the sequence framework can control the forming of bauxite ore.
Key words: sedimentary type bauxite ore; sequence stratigraphy; lacustrine facies; sedimentary differentiation; base level
