地质通报
地質通報
지질통보
GEOLOGICAL BULLETIN OF CHINA
2014年
10期
1514-1522
,共9页
董进%王永%张世红%付星梅%姚杜琳
董進%王永%張世紅%付星梅%姚杜琳
동진%왕영%장세홍%부성매%요두림
粒度%水动力%异常沉积事件%内蒙古黄旗海%磁组构
粒度%水動力%異常沉積事件%內矇古黃旂海%磁組構
립도%수동력%이상침적사건%내몽고황기해%자조구
grain size%hydrodynamics%abnormal depositional events%Huangqihai Lake,Inner Mongolia%magnetic fabric
对内蒙古黄旗海湖心、湖滨2个现代沉积剖面在前期磁组构研究的基础上,进行了沉积物粒度分析。结果显示,2个剖面从下到上都表现出粗颗粒含量逐渐增加的趋势,反映水动力逐渐增强。对比之前的磁组构结果发现,靠近湖心的HQW剖面,粒度与磁组构具有较好的对比性。HQW剖面的磁各向异性度等磁组构参数从下到上表现出逐渐增大的趋势,显示矿物定向和水流流速逐渐增强。另外,在20cm、40cm、65cm深度附近,粒度与磁组构参数都发生突然变化,表明存在水动力增大的异常沉积事件。HQE剖面的磁组构未能有效指示异常沉积事件,但其粒度分析中的细砂百分比含量和中值粒径在这些位置附近明显减小。若这是由同一异常沉积事件造成的,则表明异常沉积事件的沉积过程比较复杂,在研究异常沉积事件时不同的沉积部位需使用不同的研究方法。
對內矇古黃旂海湖心、湖濱2箇現代沉積剖麵在前期磁組構研究的基礎上,進行瞭沉積物粒度分析。結果顯示,2箇剖麵從下到上都錶現齣粗顆粒含量逐漸增加的趨勢,反映水動力逐漸增彊。對比之前的磁組構結果髮現,靠近湖心的HQW剖麵,粒度與磁組構具有較好的對比性。HQW剖麵的磁各嚮異性度等磁組構參數從下到上錶現齣逐漸增大的趨勢,顯示礦物定嚮和水流流速逐漸增彊。另外,在20cm、40cm、65cm深度附近,粒度與磁組構參數都髮生突然變化,錶明存在水動力增大的異常沉積事件。HQE剖麵的磁組構未能有效指示異常沉積事件,但其粒度分析中的細砂百分比含量和中值粒徑在這些位置附近明顯減小。若這是由同一異常沉積事件造成的,則錶明異常沉積事件的沉積過程比較複雜,在研究異常沉積事件時不同的沉積部位需使用不同的研究方法。
대내몽고황기해호심、호빈2개현대침적부면재전기자조구연구적기출상,진행료침적물립도분석。결과현시,2개부면종하도상도표현출조과립함량축점증가적추세,반영수동력축점증강。대비지전적자조구결과발현,고근호심적HQW부면,립도여자조구구유교호적대비성。HQW부면적자각향이성도등자조구삼수종하도상표현출축점증대적추세,현시광물정향화수류류속축점증강。령외,재20cm、40cm、65cm심도부근,립도여자조구삼수도발생돌연변화,표명존재수동력증대적이상침적사건。HQE부면적자조구미능유효지시이상침적사건,단기립도분석중적세사백분비함량화중치립경재저사위치부근명현감소。약저시유동일이상침적사건조성적,칙표명이상침적사건적침적과정비교복잡,재연구이상침적사건시불동적침적부위수사용불동적연구방법。
Two sections located at the center and lakeshore respectively in the Huangqihai Lake of Inner Mongolia were investigated. In this study, the grain size analysis result was given, which can be regarded as the complement to the previous magnetic fabric study of the sedimentary environment. The result of grain size analysis shows that the particles become coarser upwards in these two sec-tions, indicating increasing hydrodynamic force. A comparative analysis of the grain size and the magnetic fabric reveals that the grain size and the magnetic fabric show evident comparability in the HQW section which is located at the lake center. The magnetic fabric parameter anisotropy degree (P) shows upward increasing tendency, suggesting strong mineral oriented alignment and relatively high hydrodynamic action. In addition, at the depths of about 20cm, 40cm and 65cm, the grain size and the magnetic fabric all display ob-vious change, which further indicates abnormal depositional events with strong kinetic energy. In the HQE section which lies near the lakeshore, the fine-sand proportion and medium diameter grains show obvious decreasing although the magnetic fabric analysis fails to display any abnormal depositional events. If all these phenomena were really caused by abnormal depositional events, the depo-sition process must have been very complex and hence different methods should be employed in studying abnormal depositional events. Because the magnetic fabric is influenced not only by grain size but also by sedimentary structure, it can probably clearly re-veal abnormal depositional events at the lake center, where the hydrodynamic energy is low.