琼东南盆地古近纪沉积充填演化及其区域构造意义   总被引：21，自引：1，他引：21  

钟志洪  王良书  李绪宣  夏斌  孙珍  张敏强  吴国干 《海洋地质与第四纪地质》2004,24(1):29-36

琼东南盆地是发育于南海西北部的新生代张性断陷盆地。始新统和早渐新统崖城组属过充填型或平衡充填类型，在盆地各个断陷内均具有砂岩-泥岩-砂岩三重沉积充填结构；晚渐新统陵水组在北部坳陷带属过充填及平衡充填类型，发育砂岩-泥岩-砂岩三重沉积充填结构，而在中央坳陷带则属由砂岩-泥岩二重沉积充填结构组成的欠充填型。古近纪盆地的沉积充填结构演化反映了始新世-早渐新世断陷阶段与晚渐新世断拗阶段的盆地演化历史，其中，晚渐新世盆地断拗阶段的发育是南海海底单期扩张过程的结果。  相似文献   

南海表层沉积沟鞭藻孢囊的分布特征   总被引：2，自引：0，他引：2  

吴国鬎  孙湘君 《热带海洋学报》2000,19(1)

为研究沟鞭藻孢囊含量和组合的分布规律 ,分析了南海 38个站位的表层沉积样品。共鉴定得沟鞭藻孢囊 1 6属 2 7种 ,孢囊含量变化在 8至 92 5粒·g- 1 之间。研究区北部及靠近巴士海峡的样品孢囊含量较高 ,而南海南部的样品孢囊含量较低。孢囊含量的这一分布型式与南海表层水中浮游植物的分布特征具有一致性 ,似受表层海水营养因素控制。Spiniferites是沟鞭藻孢囊组合的优势组分 ,主要有S .ramosus,S .hyperacanthus,S .mirabilis等。孢囊组合中其它较重要的属种包括Impagidinium ,Operculodiniumcentrocarpum ,Polysphaeridiumzoharyi,Lingulodiniummachaerophorum ,Protoperidinium孢囊和Tuberculodiniumvancampoae。Spiniferites和Impagidinium的含量从陆坡往深海有增多之趋势 ,而其它类型则减少。  相似文献   

海南岛温泉特征与地下热水成因     

高芳蕾  杨小强  吴国爱  傅杨荣  陈育文 《吉林大学学报(地球科学版)》2009,39(2):281

通过对海南岛区域地质构造、岩浆岩与温泉分布的关系,以及温泉水化学和同位素分析,总结该区温泉的属性特征,阐明地下热水的成因。温泉在地势较低的琼西北和琼东南呈对称性条带状分布。水质类型大多为低矿化的重碳酸盐型,呈碱性,含较高的氟和硅;第四系滨海区受海水影响则表现为氯化钠型。温泉的氢、氧、氦同位素及气体组分揭示地下热水起源于大气降水,大气降水在地壳浅部循环过程中被围岩加热成地下热水。地热资源为中低温对流型地热系统,热储温度为59.5～161.2 ℃,平均128.5℃,是由偏高的区域热流在深部供热的,与岩浆作用无关。地下热水的出露受区内NE、EW向深大断裂控制。  相似文献   

Analysis on Double-difference Earthquake Location and the Seismicity Pattern of the Yangjiang Earthquake Sequences     

Kang Ying  Yang Xuan  Huang Wenhui  Chen Xing  Chen Guimei  Lin Wei  Wu Huadeng 《中国地震研究》2008,22(1):73-81

The locations of about 400 earthquakes in Yangjiang, Guangdong Province are determined using the double, difference earthquake location algorithm （DDA）. The seismicity pattern becomes concentrated from discrete grids. The rupture characteristics of the Yangjiang earthquake sequence show a conjugated distribution in NW and NE directions. The major distribution trends NE and dips NE with an angle of 30^o and a length of 30km,and the minor distribution trends NW and dips SE with an angle of 30^o and a length of 20km. The focal depth is 5km - 15km. The distribution of the Enping earthquake sequence,which is not far from Yangjiang,is NW-trending. The relationship between hypocenter distribution and geological structure is discussed.  相似文献   

南海北部陆坡晚第四纪有机壁浮游藻类记录及其古环境 …   总被引：5，自引：1，他引：4  

吴国Xuan  孙湘君 《海洋地质与第四纪地质》2000,20(2):57-63

通过９２个样品分析,发现南海北部陆坡末次冰期以来２物中有机壁浮游藻类输入通量在新仙女木期和早全新世明显高于其它时期新仙女山的输入通量峰值及不同于Ｓｐｉｎｉｆｅｒｉｔｅｓｓｐｐ．组合（较暖期）和Ｐｒｏ－ｔｏｐｅｒｉｄｉｎｉｏｉｄ类孢囊组合（较冷期）的Ｏｐｅｒｃｕｌｏｄｉｎｍｉｕｍ ｃｅｔｒｏｃａｒｐｕｍ组合,表明当时表层少环境较为特殊,可能是水温偏低且较富营养的条件,早全新世的有机壁浮游藻类高输入通  相似文献   

Otolith microchemical evidence revealing multiple spawning site origination of the anadromous tapertail anchovy (Coilia nasus) in the Changjiang (Yangtze) River Estuary     

Zhongya Xuan  Tao Jiang  Hongbo Liu  Xiubao Chen  Jian Yang 《海洋学报(英文版)》2023,42(1):120-130

The estuarine tapertail anchovy(Coilia nasus) is a high-value commercial fish. Estimating the spawning site or hatchery origin and habitat is essential for its conservation. This study aimed to determine the habitat use and life history characteristics of C. nasus from the Changjiang River Estuary. We investigated the environmental signatures of strontium(Sr) and calcium(Ca) in the otoliths of the collected specimens using electron probe microanalysis; additionally, we examined their gonadal mat...  相似文献   

Numerical investigation of the effect of seasonal variations of depthof-closure on shoreline evolution     

Xuan Tinh Nguyen  Minh Thanh Tran  Hitoshi Tanaka  Trung Viet Nguyen  Yuta Mitobe  Cong Dien Duong 《国际泥沙研究》2021,36(1):1-16

The current study presents the effects of seasonal variations in the depth-of-closure(Dc)on shoreline evolution using a numerical,one-line shoreline model.Beach erosion of the southern beach of the Nha Trang Coast,which is located in south central of Vietnam,is selected as the study area.This study area is immensely influenced by the tropical monsoon climate that has a clear pattern of large waves in the northeast monsoon season and calm waves in the non-monsoon season.The analysis of the long-term measured shoreline variations from a video-camera system has found a strong correlation of these variations to the monsoon-dominated wave characteristics in the Nha Trang Bay.Therefore,a new approach for determining the depth-of-closure with consideration of the seasonal wave climate changes is purposed in the current study.By implementing this new approach into a numerical,one-line shoreline model,it is found that the seasonal variations of Dc appear to better describe the periodical shoreline evolution due to the monsoon-dominated wave characteristics for the Nha Trang Coast.Such important findings are considered to commonly apply for monsoon-dominated coastal regions in general.These findings are useful information not only for scientific readers but also for the coastal authorities and managers in order to make better countermeasure plans against this kind of erosion mechanism in the future.  相似文献   

Accumulation conditions and enrichment mechanism of Shale gas in Nangao section, Yangtze Platform,S.China     

LUO Chao  LIU Shugen  SUN Wei  RAN Bo  YANG Di  ZHANG Xuan  WANG Shiyu  YE Yuehao 《《地质学报》英文版》2013,87(Z1):574-575

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Estimation of tropical cyclone parameters and wind fields from SAR images     

ZHOU Xuan  YANG XiaoFeng  LI ZiWei  YU Yang  BI HaiBo  MA Sheng  LI XiaoFeng 《中国科学:地球科学(英文版)》2013,56(11):1977-1987

The traditional method of Synthetic Aperture Radar(SAR)wind field retrieval is based on an empirical relation between the near surface winds and the normalized radar backscatter cross section to estimate wind speeds,where this relation is called the geophysical model function(GMF).However,the accuracy rapidly decreases due to the impact of rainfall on the measurement of SAR and the saturation of backscattered intensity under the condition of tropical cyclone.Because of no available instrument synchronously monitoring rain rate on the satellite platform of SAR,we have to derive the precipitation of the SAR observation time from non-simultaneous passive microwave observations of rain in combination with geostationary IR images,and then use the model of rain correction to remove the impact of rain on SAR wind field measurements.For the saturation of radar backscatter cross section in high wind speed conditions,we develop an approach to estimate tropical cyclone parameters and wind fields based on the improved Holland model and the SAR image features of tropical cyclone.To retrieve the low-to-moderate wind speed,the wind direction of tropical cyclone is estimated from the SAR image using wavelet analysis.And then the maximum wind speed and the central pressure of tropical cyclone are calculated by a least square minimization of the difference between the improved Holland model and the low-to-moderate wind speed retrieved from SAR.In addition,wind fields are estimated from the improved Holland model using the above-mentioned parameters of tropical cyclone as input.To evaluate the accuracy of our approach,the SAR images of typhoon Aere,typhoon Khanun,and hurricane Ophelia are used to estimate tropical cyclone parameters and wind fields,which are compared with the best track data and reanalyzed wind fields of the Joint Typhoon Warning Center(JTWC)and the Hurricane Research Division(HRD).The results indicate that the tropical cyclone center,maximum wind speed,and central pressure are generally consistent with the best track data,and wind fields agree well with reanalyzed data from HRD.  相似文献   

Characteristics and environmental significance of Ca, Mg, and Sr in the soil infiltrating water overlying the Furong Cave, Chongqing, China   总被引：2，自引：0，他引：2  

LI JunYun  LI TingYong  WANG JianLi  XIANG XiaoJing  CHEN YunXuan  LI Xuan 《中国科学:地球科学(英文版)》2013,56(12):2126-2134

This paper explores the influence of the local meteoric conditions,the overlying soil on the concentrations of Ca,Mg,and Sr,and the ratios of Mg/Ca,Sr/Ca,and Mg/Sr in soil infiltrating water(SIW).An in situ monitoring program was carried out above the Furong Cave throughout 2010 to collect data on SIW,monthly temperature and rainfall,and the geochemical composition and granularity of soils.The discharge of SIW responded quickly to the local rainfall,and its residence time was the primary factor affecting the Ca,Mg,and Sr content of the SIW.The high concentrations of Ca,Mg,and Sr in the SIW during April should be attributed primarily to the prolonged residence of SIW in the soil during the local dry seasons of winter and early spring.The maximum Mg/Sr ratio also occurred in April.The ratio of Mg/Ca in SIW is positively correlated with prolonged residence time and with high temperatures,which do not strongly affect the ratio of Sr/Ca.The Mg/Ca ratio was lowest when the Sr/Ca ratio was highest because plant metabolism increased the absorption of Ca and Mg,but not Sr,and also because higher temperatures enhanced the dissolution of Mg more than that of Sr.These different responses of Mg and Sr to temperature increases resulted in high Mg/Sr ratios during July and August.  相似文献