| 吉林龙岗火山群火山碎屑基浪堆积特征与成因机理 |
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| 引用本文： | 徐德兵,白志达,张秉良,洪汉净.吉林龙岗火山群火山碎屑基浪堆积特征与成因机理[J].沉积学报,2005,23(1):60-66. |
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| 作者姓名： | 徐德兵 白志达 张秉良 洪汉净 |
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| 作者单位： | 1.中国地质大学,北京 10008; |
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| 摘 要： | 吉林龙岗火山群火山碎屑基浪堆积是中国少数保存较好的、近代喷发的低平火山区之一。基于岩性、岩相与相序的识别与分析,火山碎屑基浪堆积序列由分选性和磨圆度较差的玄武质砂、砾和火山灰构成的毫米级-厘米级厚高频率韵律有序叠置而成,堆积物中发育大量的块状层理、似丘状层理、低角度板状交错层理、槽泊层理、平行层理、冲蚀槽等堆积构造。横向上低平火山由内至外其碎屑粒度、堆积构造、厚度存在着一定规律变化,与易混淆的火山岩区地面流水沉积和火山碎屑流堆积物存在明显的差别。岩浆射汽喷发晚期往往伴随斯通博利式喷发和夏威夷式熔岩流,三者构成一个完整火山活动旋回。
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| 关 键 词： | 低平火山 基浪堆积 成因机理 吉林龙岗 |
| 文章编号： | 1000-0550(2005)01-0060-07 |
| 收稿时间： | 2004-02-20 |
| 修稿时间： | 2004年2月20日 |
Characteristic and Genetic Mechanism of Pyroclastic Base-Surge Deposits of Volcanic Swarm in Longgang Area, Jilin Province |
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| XU De-bin,BAI Zhi-da,ZHANG Bing-lian,HONG Han-jing.Characteristic and Genetic Mechanism of Pyroclastic Base-Surge Deposits of Volcanic Swarm in Longgang Area, Jilin Province[J].Acta Sedimentologica Sinica,2005,23(1):60-66. |
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| Authors: | XU De-bin BAI Zhi-da ZHANG Bing-lian HONG Han-jing |
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| Institution: | 1.China University of Geosciences, Beijing 1000832;2.Institute of Geology, China Seismological Bureau, Beijing 100029 |
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| Abstract: | Pyroclastic base-surge deposits of volcanic cluster in the Longgang region of Jilin Province is one of the few neoteric maar deposits which are preserved in good condition in China. Based on the lithological characters, lithofacies and sequences, pyroclastic base-surge sequence consists of millimeter-scale to centimeter-scale frequent cyclothemthatconstitute a regularly vertical stacking pattern, which is made of sub-edge angle and worse graded basaltic sand, lapillus and tuff ash. Mass bedding, dune-like structure, low angle cross-bedding, chute and pool structure, parallel bedding and scouring through are widely developed in base-surge deposits. Pryoclastic granularity, deposit structures and thickness are developed with a regularly transverse disciplinarian from inner to external of maar. The characteristicof pyroclastic ejecta is more different with ignimbriteand alluvial and/or diluvial deposits from volcanic cone. Bits of strombolian-type scoria and Hawaii-type effusive lava may accompany lately after Phreatomagmatic eruption, they constitute a eruptive activity cycle in its entirely. |
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| Keywords: | maar base-surge deposits genetic mechanism Longgang area in Jilin Province |
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