沉积与特提斯地质
沉積與特提斯地質
침적여특제사지질
SEDIMENTARY GEOLOGY AND TETHYAN GEOLOGY
2014年
4期
1-12
,共12页
刘丽华%汪瑞良%傅恒%鲁静
劉麗華%汪瑞良%傅恆%魯靜
류려화%왕서량%부항%로정
东沙隆起%珠江组%生物礁%地震反射
東沙隆起%珠江組%生物礁%地震反射
동사륭기%주강조%생물초%지진반사
Dongsha uplift%Zhujiang Formation%organic reef%seismic reflection
东沙隆起珠江组生物礁是珠江口盆地重要的储层类型,礁灰岩主要为珊瑚藻灰岩,分为骨架岩、粘结岩及障积岩。研究区生物礁发育于开阔台地、台地边缘及台地前缘斜坡3类沉积相中,生物礁类型可分为台内点礁、台地边缘堡礁及台缘斜坡塔礁,以台地边缘堡礁为主。珠江组沉积早期,东沙隆起发育滨岸砂质沉积;中期海水逐渐淹没东沙隆起,形成镶边浅水碳酸盐台地,发育生物礁;晚期海侵台地逐渐淹没消亡,被浅海陆棚泥质沉积代替。流花台地厚度最大,最厚达563m,台地顶面地震强反射使外形轮廓清晰,台地内部中-弱振幅至空白反射,连续性降低;惠州台地厚度较流花台地薄,厚度多大于100m,顶界面强反射轮廓清晰,内部层状反射能量强-中振幅、高-中连续、中-低频,局部空白反射;陆丰台地厚约30m,只有一个高连续的强振幅。生物礁地震响应以丘形、箱型、低丘-透镜状为特征,礁顶常为强振幅,内部为波状、有时见前积结构,翼部可见上超和披覆现象等。
東沙隆起珠江組生物礁是珠江口盆地重要的儲層類型,礁灰巖主要為珊瑚藻灰巖,分為骨架巖、粘結巖及障積巖。研究區生物礁髮育于開闊檯地、檯地邊緣及檯地前緣斜坡3類沉積相中,生物礁類型可分為檯內點礁、檯地邊緣堡礁及檯緣斜坡塔礁,以檯地邊緣堡礁為主。珠江組沉積早期,東沙隆起髮育濱岸砂質沉積;中期海水逐漸淹沒東沙隆起,形成鑲邊淺水碳痠鹽檯地,髮育生物礁;晚期海侵檯地逐漸淹沒消亡,被淺海陸棚泥質沉積代替。流花檯地厚度最大,最厚達563m,檯地頂麵地震彊反射使外形輪廓清晰,檯地內部中-弱振幅至空白反射,連續性降低;惠州檯地厚度較流花檯地薄,厚度多大于100m,頂界麵彊反射輪廓清晰,內部層狀反射能量彊-中振幅、高-中連續、中-低頻,跼部空白反射;陸豐檯地厚約30m,隻有一箇高連續的彊振幅。生物礁地震響應以丘形、箱型、低丘-透鏡狀為特徵,礁頂常為彊振幅,內部為波狀、有時見前積結構,翼部可見上超和披覆現象等。
동사륭기주강조생물초시주강구분지중요적저층류형,초회암주요위산호조회암,분위골가암、점결암급장적암。연구구생물초발육우개활태지、태지변연급태지전연사파3류침적상중,생물초류형가분위태내점초、태지변연보초급태연사파탑초,이태지변연보초위주。주강조침적조기,동사륭기발육빈안사질침적;중기해수축점엄몰동사륭기,형성양변천수탄산염태지,발육생물초;만기해침태지축점엄몰소망,피천해륙붕니질침적대체。류화태지후도최대,최후체563m,태지정면지진강반사사외형륜곽청석,태지내부중-약진폭지공백반사,련속성강저;혜주태지후도교류화태지박,후도다대우100m,정계면강반사륜곽청석,내부층상반사능량강-중진폭、고-중련속、중-저빈,국부공백반사;륙봉태지후약30m,지유일개고련속적강진폭。생물초지진향응이구형、상형、저구-투경상위특정,초정상위강진폭,내부위파상、유시견전적결구,익부가견상초화피복현상등。
The reef limestones in the Zhujiang Formation on the Dongsha uplift may be classified into three types:framestone,bindstone and bafflestone developed in the open platform,platform-margin and foreslope facies,and composed of the intraplatform patch reefs,platform-margin barrier reefs and foreslope pinnacle reefs,respectively. During the early stages of the deposition of the Zhujiang Formation,the littoral sandy deposits were initiated on the Dongsha uplift,followed by the rimmed shallow-water carbonate platforms during the middle stages. During the late stages,the carbonate platforms were gradually drowned and consumed by trangressions,and then the shallow shelf muddy deposits were accentuated. Among the carbonate platforms,the Liuhua platform has a maximum thickness of 563 m,and displays strongly seismic reflection on the topmost part while moderate-weak amplitudes and reflection and poor continuity in the interior of the platforms. The Huizhou platform with a thickness of more than 100 also displays strongly seismic reflection on the topmost part while strong-moderate amplitudes,high-moderate continuity and moderate-low frequency and locally blank reflection in the interior of the platforms. The Lufeng platform only with a thickness of about 30 m exhibits highly continuous strong amplitudes. The seismic reflection configurations generally display the mound,box,low hills-lenticular forms. The onlapping and draping can be observed as well.