中国大陆及邻区中生代—新生代大地构造与环境变迁   总被引：68，自引：12，他引：68  

万天丰  朱鸿 《现代地质》2002,16(2):107-120

在系统研究古地磁、周边板块的运动学特征、板内变形、构造应力场和沉积古地理资料的基础上 ,恢复了中国大陆及邻区中、新生代 6个时期的大地构造演化特征、构造古地理 ,并进而探讨了对环境变迁的影响。 6个时期的划分、构造特征及其古地理环境分别为 :印支期 (2 5 0～ 2 0 8Ma) ,NE -SW向缩短 ,中国大部分大陆完成拼合 ,南方以海为主 ,北方以陆地为主 ;燕山期 (2 0 8～ 135Ma) ,NW -SE向缩短 ,大陆地块逆时针旋转 2 0°～ 30° ,东部形成高地 ,西部为低地 ;四川期 (135～ 5 2Ma) ,NE -SW向缩短 ,以盆岭地形为主 ;华北期 (5 2～ 2 3 3Ma) ,太平洋板块第一次向西俯冲、挤压 ,中国东部形成 3条东西向山脉和 4个汇水盆地 ;喜马拉雅期 (2 3 3～ 0 78Ma) ,印度板块与欧亚大陆碰撞 ,青藏高原隆升 ,其他地块相对沉降 ;新构造期 (0 78Ma以来 ) ,周边各板块保持相对均衡状态 ,逐步构成现代地貌。研究表明 ,大地构造是古地理环境变化的主要控制因素。  相似文献   

辽南大莲泡沉积物的沉积特征及古环境变化     

李雪铭 《沉积学报》1997,(1)

辽南大莲泡是形成于冰后期的一个现已干涸的小型山间湖泊。对大莲泡沉积物粒度作一般分析，并用对应因子分析法作了计算分析，结果表明：大莲泡沉积物粒度分布主要受入湖的沟谷泥石流、河流和湖泊沉积作用控制。即下层以泥石流沉积为主；中层以湖泊沉积为主；上层以河流作用为主。据此并结合孢粉分析资料（主要以湿生沼生和旱生、盐生草本孢粉带更替为依据），初步恢复了大莲泡沉积环境的演变过程。全新世高海面在辽南地区是存在的，大莲泡与海相通的特殊位置及地层特征和孢粉特点揭示在全新世气候最适宜期海水在涨潮时曾作过短暂的停留，高海面在渤海沿岸出现位置不超过现代海面之上５ｍ。  相似文献   

Characteristics of fault rocks and paleo-earthquake source along the Koktokay-Ertai fault zone,Xinjiang,China     

史兰斌  林传勇  陈孝德  张小鸥  柏美祥 《地震学报(英文版)》1997,10(3):365-373

ＣｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆｆａｕｌｔｒｏｃｋｓａｎｄｐａｌｅｏｅａｒｔｈｑｕａｋｅｓｏｕｒｃｅａｌｏｎｇｔｈｅＫｏｋｔｏｋａｙＥｒｔａｉｆａｕｌｔｚｏｎｅ，Ｘｉｎｊｉａｎｇ，ＣｈｉｎａＬＡＮＢＩＮＳＨＩ１）（史兰斌）ＣＨＵＡＮＹＯＮ...  相似文献   

柴达木贝壳堤剖面元素地球化学与环境演变   总被引：12，自引：7，他引：5       下载免费PDF全文

张文翔  张虎才  雷国良  杨伦庆  牛洁  常凤琴  杨明生  樊红芳 《第四纪研究》2008,28(5):917-928

通过对柴达木盆地察尔汗古湖贝壳堤沉积物中酸溶与残留(酸不溶)组分中常、微量元素及其元素对的分析,并结合酸溶与残留组分中常、微量元素相关性对比,讨论了贝壳堤剖面元素地球化学指标和沉积环境之间的关系,指出酸溶组分中的常量、微量元素及其元素对可以作为湖泊和古气候演化良好的代用指标;残留组分中的元素及元素对与原岩及其风化程度紧密相关,因此,酸溶组分与残留组分中的常量和微量元素在对于环境响应模式存在一定差异,应该将二者分开研究以避免对元素所携带环境信号解译的偏差。根据元素地球化学指标重建了43.5～22.4cal.kaB.P.(39.7～17.5kaB.P.¹⁴C年代)柴达木盆地察尔汗古湖高湖面期间古气候与环境演变过程:43.5～31.7kaB.P.期间酸溶组分中元素含量总体较低,残留组分中元素含量相对较高,且湿润度值((Fe₂O₃+Al₂O₃)/(MgO+CaO),或H)处于高值段,而Ca/Mg,Fe/Mn和Rb/Sr则处于低值段,指示了温暖湿润的气候环境,古湖泊水体增加;其中37.8～31.7kaB.P.期间酸溶组分中元素含量多出现最低值,残留组分中元素含量富集,H值较高,而Ca/Mg,Fe/Mn和Rb/Sr此段均值最小,表明此时为环境的最适宜期,此期间降雨充沛,湖泊处于高湖面;在31.7～22.4kaB.P.期间酸溶组分中元素含量普遍较高,残留组分中元素含量相对富集,且Ca/Mg,Fe/Mn和Rb/Sr处于高值段波动,H值处在低值段,指示气候环境恶化,降水逐渐减少,古湖泊水体萎缩;在约22.4kaB.P.气候快速恶化,形成石盐结晶,高湖面历史结束。柴达木盆地该期高湖面及其演化过程可与腾格里沙漠和额济纳盆地-巴丹吉林沙漠高湖面记录进行对比,揭示了大范围气候变化的历史。  相似文献   

南黄海埋藏古三角洲   总被引：10，自引：0，他引：10  

李凡  张秀荣  李永植  李本兆 《地理学报》1998,(3)

应用高分辨地球物理测量手段在南黄海中部深水区测量,发现了大面积以前积与前人所述反射结构为特征的埋藏三角洲地层。经过岩芯沉积成份分析、有孔虫组合、１４Ｃ年龄测定,证明是晚更新世晚期海退时期的古黄河三角洲沉积,并能与相邻的地层时代和沉积环境对应。结合华北平原与陆架区埋藏古河道的研究证明,晚更新世晚期低海面时期已经形成了黄河,并且流进了渤、黄海陆架海区。  相似文献   

南京汤山猿人生存古环境重建探讨   总被引：7，自引：1，他引：6  

朱诚  张建新 《地理科学》1998,18(5):433-441

由铀系法测定的５组化石年代数据表明,南京汤山猿人年代为２８０￣４３０ｋａＢ．Ｐ．之间;以剑齿象,李氏野猪,肿骨鹿,葛氏斑鹿、三门马等为主的古动物群化石,证实了南京猿人生活在中更新世中期偏晚,距今约３５０ｋａ左右。鉴定的孢粉主要为喜暖湿、暖干的落叶阔叶与针叶及蕨类混合林以及偏干凉的（松）针叶林、既未发现反映寒冷的云杉、冷杉、也未发现反映干旱的黄连木,表明本区猿人生存时并未经历中更新世冰期时的冰川环境  相似文献   

古水文地质方法在研究下庄花岗岩型铀矿床中的应用   总被引：1，自引：0，他引：1  

刘金辉  李学礼 《华东地质学院学报》1998,21(4):330-335

本文在分析华南下庄铀矿田区域地质背景、古气候条件的基础上,运用古水文地质方法对该区构造－古水文地质分斯、分区进行了划分,确定了下庄铀成矿古水热系统的补给区、径流区和排泄区位置,并对该水热系统中铀成矿作用水文地质过程作了简要的归纳。  相似文献   

古海洋溶解氧与缺氧和富氧问题研究   总被引：26，自引：0，他引：26  

王成善  胡修棉  李祥辉 《海洋地质与第四纪地质》1999,19(3):39-47

西藏南部晚白垩世红色灰岩层为大洋富氧条件下的沉积产物,红色灰岩层内有机碳极低,生物极其繁盛,碳同位素偏低,但从上往下又呈增高趋势。溶解氧含量在古海洋演化史中是非线形波动变化的,既有全球溶解氧含量偏低时期（缺氧条件）,也有全球溶解氧含量偏高时期（富氧条件）,古海洋溶解氧含量重建和富氧问题的解决对于理解大洋循环、古气候、生命绝灭、地质事件以及有机质演化具有十分重要的科学意义  相似文献   

Revisiting Late Quaternary Slip-rate along the Maqu Segment of the Eastern Kunlun Fault,Northeast Tibet   总被引：1，自引：0，他引：1  

LI Jian  ZHANG Yueqiao  LI Hailong  XIONG Jinhong  LI Jianhua  WU Tairan 《《地质学报》英文版》2016,90(2):486-502

The Late Quaternary slip rate along the Maqu segment of the eastern Kunlun Fault was estimated using a combination of high-resolution remote sensing imagery interpretation, field observations and differential Global Positioning System(GPS) measurements of offset river terraces, and 14 C dating of snail shells collected from offset risers. The results show that the left-slip rate along the segment is 3–5 mm/a, and that the vertical slip rate is 0.3–0.5 mm/a. Both the horizontal and vertical slips on the segment remain consistent over a distance of ~100 km. It means that no slip gradient as previously suggested occurred along the Maqu segment, and which thus might behave as an independent seismogenic fault. Judging from multiple relationships among young terrace offsets, we infer that co-seismic surface rupture produced by a characteristic earthquake with a magnitude of Ms7.0–7.5 on the Maqu fault could generate a horizontal slip of 4.5–5 m and a vertical slip of 0.45–0.5 m, with a corresponding ratio(Dh/Dv) of about 9. Two surface rupture events must have occurred over the past 3300 years, the latest one possibly between 1485 cal BP and 1730 cal BP.  相似文献   

ACTIVITY CHARACTERISTICS OF THE HUASHAN PIEDMONT NORMAL FAULT: INSIGHTS FROM FLUVIAL GEOMORPHIC PARAMETERS          下载免费PDF全文

WANG Yi-zhou  ZHENG De-wen  ZHANG Hui-ping  LI Chao-peng  HAO Yu-qi  ZHANG Rui 《地震地质》1979,42(2):382-398

The Huashan piedmont fault, forming a part of the southern margin of the Weihe graben, is one of the important normal faults that control the subsidence of the intracontinental rift. Developing on the footwall of the fault, the Huashan block has experienced rapid cooling during the Cenozoic, especially since the early-middle Miocene. Mountain exhumation causes and transports a great amount of sediments to the adjacent hanging wall, setting a typical case of mountain-basin coupling system. Studies on active tectonics, historical and paleo earthquakes and field investigations reveal that the middle section(Huaxian-Huayin)of the fault is much more active than the west(Lantian-Huaxian)and east(Huayin-Lingbao)sections.
We extracted channel profiles of rivers that originate from the main water divide of the northern flank of the Huashan Mountain. Based on the method of slope-area analysis and the integral approach, we identified knickpoints, calculated channel concavity and steepness indices, and constructed paleo river profiles. Of most rivers, the concavities are within a relatively narrow range of 0.3~0.6, with no obvious correlation with tectonics. However, channel steepness and knickpoint distribution vary spatially. In the east section, rivers are under steady-state with smooth, concave-up channels and lower steepness((104±30)m^0.9). In the other two sections, rivers are mainly under transient state with slope-break knickpoints. For the channel segments below knickpoints, steepness indices are much higher in the middle section((230±92)m^0.9)than in the west((152±53)m^0.9). Thus, the variance of fault activity can be reflected by channel steepness pattern. Above the knickpoints, channel steepness indices are much lower(middle(103±23)m^0.9, west(60±14)m^0.9). What's more, we found a statistically significant power-law scaling between knickpoint retreat distance and catchment drainage area. Thus, we attributed these knickpoints to be the results of recent rapid uplift of the Huashan block. The relief of paleo channels(middle(1000±153)m, west(751±170)m)accounts for~60%~80% of the relief of modern rivers(middle(1323±249)m, west(1057±231)m), which means that ~20%~40% of modern channel relief was caused by the episode of the rapid uplift. Assuming a balance between the rates of rock uplift and downstream river incision, a power-law function between uplift rates and channel steepness can be derived. According to the fault throw rates of the middle section 1.5~3mm/a(since late Pleistocene), we constrained slope exponent n~0.5 and channel erodibility K~1.5×10^-4m^0.55/a. Combining the knickpoint age formula, we estimated that the rapid mountain uplift/fault throw began at ~(0.55±0.25)Ma BP. Therefore, the middle of the Huashan piedmont fault is more active than the west and east sections. The fast fault throw of the west and middle sections since the middle Pleistocene has caused rapid mountain uplift and high topographic relief.  相似文献