CAJ | 학술논문

滇东南中三叠统法郎组是重要的含锰地层,前人对其沉积环境的认识却存在着深水浊流沉积和浅水潮坪沉积的争议.本文通过对建水-开远地区典型剖面的研究,认为法郎组为浊积扇沉积.法郎组底部为碳酸盐滑塌沉积、碎屑流沉积与泥岩粉砂岩互层,中上部逐渐由外扇渐变为中扇辫状水道和辫状水道间沉积,顶部为内扇补给水道和溢岸沉积.相对海水深度总体表现为在拉丁早期逐渐加深,到拉丁中晚期有逐渐变浅.锰矿层主要发育在底部的碎屑流沉积中,其形成可能与拉丁早期相对水深的增高有关.
전동남중삼첩통법랑조시중요적함맹지층,전인대기침적배경적인식각존재착심수탁류침적화천수조평침적적쟁의.본문통과대건수-개원지구전형부면적연구,인위법랑조위탁적선침적.법랑조저부위탄산염활탑침적、쇄설류침적여니암분사암호층,중상부축점유외선점변위중선변상수도화변상수도간침적,정부위내선보급수도화일안침적.상대해수심도총체표현위재랍정조기축점가심,도랍정중만기유축점변천.맹광층주요발육재저부적쇄설류침적중,기형성가능여랍정조기상대수심적증고유관.
There is still debate concerning the sedimentary environments of the Middle Triassic Falang Formation as important manganese-bearing strata in southeastern Yunnan: a deep-marine turbidite fan or a shallow-water tidal flat. The authors in this study contend, on the basis of representative sections in the Jianshui-Kaiyuan region, that the Falang Formation represents the turbidite fan deposits. The lowermost part of the Falang Formation is made up of the carbonate slump deposits, debris flow deposits and the interbeds of mudstone and siltstone, followed by the outer-fan to mid-fan braided channel and braided interchannel deposits in the middle-upper part, and inner-fan recharge channel and overbank deposits in the uppermost part of the Falang Formation. On the whole, the sea water became progressively deeper during the early Ladinian, and shallower during the middle and late Ladinian. The manganese ores are mostly hosted in the debris flow deposits in the lowermost part of the Falang Formation, implying that the origin of the manganese ores may be associated with relative sea-level rise during the early Ladinian.