福建省石炭纪—白垩纪古生物群主要特征

通过总结福建省石炭纪－白垩纪地层中Ｔｉｎｇ及珊瑚、腕足、双壳、菊石、叶肢介和植物等门类的古生物化石组合特征,为省内石炭纪－白垩纪地层的划分、对比提供重要的依据。     

松辽盆地白垩纪孢粉颜色指数与有机质成熟度

The relatiouship between posen colour and the degree of maturity of organic material is discussed with regard to petroleum formation and evolution as typified by Daqing oil field in Cretaceous system, central Songliao basin, Northeast China. Colour variation of pollen is considered as a function of sedimentary environment and metamorphism. Pollen colour is divided into seven grades and the degree of metamorphism is studied in terms of this colour index. Results show that the pollen colonr index of the strata at depth of 1000-3000m (stratigraphieally from the first section of Liangjiang formation to the upper Quantou formation) ranges from 2.5 to 5, corresponding to an ancient temperature of 60--140℃. This is the most.optimum strata for oil-generation. Strata beneath the lower Quantou formation under 3000 m with colour index in excess of 5 and ancient temperature of over 140℃ should be favorable for gas accumulation. For strata at shallower depth than 100O m, stratigraphically above the second section of Liengjiang formation, which is characterized by a colour index of 1--1.5 and a temperature of lower than 600℃, the maturity degree is lower than that necessary for oil-generation.     

塔里木盆地侏罗-白垩纪古气候研究

以沉积学理论为指导,结合岩石学和矿物学等学科,通过对塔里木盆地岩相和重矿物类型和组合及其稳定性等的分析,详细探讨了塔里木盆地侏罗纪—白垩纪的岩相特征,并重建古气候的演化特征。塔里木盆地侏罗纪主要属于温暖湿润气候,晚侏罗纪后期到早白垩世属于干旱炎热气候。     

浙江首次发现大规模恐龙化石群

近日,在浙江金衢白垩纪盆地东阳一带,首次发现一组约8000万年前的晚白垩世恐龙、鸟和翼龙脚印遗迹化石群。该化石群共有3层,已发现翼龙等7种不同种类的脚印化石,共90多个脚印。     

对大同云岗龙沉积环境的分析

本文通过岩性、岩相等资料的综合研究对大同云岗龙化石剖面进行沉积环境分析,结果表明其沉积环境为干旱-半干旱的条件下的扇三角洲沉积,并详细讨论了扇三角洲沉积体系中各岩相的沉积亚相和沉积微相,恢复了云岗龙的沉积环境。     

二连浩特国家地质公园

正内蒙古二连浩特国家地质公园位于市区东北9公里处的额仁诺尔盐池一带,是内蒙古最早载入国际古生物史册的恐龙化石产地。二连盆地的恐龙化石生物群是我国晚白垩纪恐龙生物群的代表,恐龙化石种类多、分布广、保存完好,反映了世界晚白垩纪恐龙生物群的主要生物群特征;该地区恐龙化石出露良好,层序完整,上下接触关系清楚,是研究亚洲地区晚白垩纪的典型地区。     

云南思茅盆地景谷地区下白垩统曼岗组风成砂岩沉积学特征及其古气候意义

本文通过野外剖面的观察和实测,室内薄片鉴定、阴极发光分析、粒度分析、扫描电镜及能谱测试分析,研究了云南思茅盆地景谷地区下白垩统曼岗组风成砂岩沉积学特征,详细了解了风成砂岩的发育特征,以期为研究区白垩纪古气候研究提供新的资料,为我国钾盐勘探提供一定的地质依据和新的思路。研究结果表明:1研究区曼岗组主要出露一套中—细粒石英砂岩、岩屑石英砂岩,发育中—大型交错层理、平行层理,碎屑颗粒分选中等-好,以次圆状-圆状为主,孔隙不发育,杂基含量少;2曼岗组中段发育具平行层理的石英砂岩,粒度分布呈双众数,带状分布,石英颗粒为浑圆状,颗粒表面见Fe、Mn质薄膜,颗粒表面具明显的碟形坑等特征,属于典型的风成砂岩,初步判定其沉积环境为风成沙丘和丘间沉积;3景谷地区下白垩统曼岗组风成砂岩,整体表现为干热型气候,曼岗组中段为丘间沉积,曼岗组上段和下段为沙丘沉积。其在搬运沉积成岩过程中经历了强烈的物理、化学风化作用,整体表现为氧化环境,风力较大,风速稳定,持续时间长。此外,可能还经历了一段时期的湿润性气候环境,这可能与大气降水、大气环流带的迁移,以及白垩纪海侵作用等有关。     

大鱼的脆弱

6500万年前的白垩纪末期,一颗小行星撞击了地球，地球上烟尘漫布，藻类和植物的光合作用受到抑制，最终导致包括恐龙在内的几千种生物的灭绝,一些大型鱼类也在那次大灭绝中从地球上消失。最近,科学家通过研究推测，大型的掠食性鱼类比其他鱼类更容易灭绝,掠食性鱼类体型较大、上下颚闭合速度快,它们以捕食其他鱼类为生，是海洋中的顶级捕食者。但是，它们的个体成熟慢、种群发展速度慢。位于食物链的顶端意味着大鱼们缺少天敌，但那里同时是一个危险的位置——科学家表示，在灭绝事件中，受到最严重打击的往往是大鱼。     

牛头山地区玄武岩类的高压分异作用

The Nutoushan basaltic cone, eonsisting of subalkali (quartz-tholeiite and olivinetholeiite) and alkali basalts, is Late Tertiary in age. Its major characteristics are generalized as follows: (1) Both early subalkali and late alkali basalts are formed under the same geological environment. (2) The continuity in chemical composition from snbalkali to alkali and the low FeO/MgO in alkali basalts show that they arc the products of cognate magmatic diffcrcntiation. (3) The change from low REE abundance and weak enrichment of LREE in subalkali to high REE abundance and strong enrichment of LREE in alkali basalts indicates obvious REE cnrichment and fractionation during magmatic differentiation.Weak positive Eu anomalies in the REE patterns arc indicative of their formation under low oxygen fugacity conditions. (4) According to the calculated values, 70-75% of the primary olivine tholeiitic magma had been separated as subalkaline basalic magma, the rest residual magma became alkaline basaltic magma. This result is consistent to the field observation that the outcrop area of subalkali basalts is four times as much as that of alkali basalts. (5) The basaltic rocks of Nutoushan show an S-type distribution straddling the thermal barrier on Ol‘-Ne‘-Qu‘ diagram and an evolution tendency for Ne to increase with increasing FeO/MgO. This is in agreement with the melting experimental data on olivine basalts at 10-20 kb. (6) Mantle-derived inclusions (spinel lherzolite) in this area occur in both alkali olivine basalts and olivine tholeiites. The latter is of extremely rare oceurrence. The formation temperature and pressure of the inclusions in alkali basalts and olivine tholeiites have been calculated. The results silow that the alkaline basaltic magma was separated from the subalkaline basaltic magma at about 20 kb. Basaltic rocks in Nutoushan were formed through the soealled “high pressure differentiation”, that is, at about 20 kb the crystallization of clinopyroxene and orthpyroxene resulted in the separation of subalkaline basaltic magma from the primary olivine tholeiitic magma, and then the residue gradually became alkaline olivine basaltic magma.     

库车——“红色的山崖”

天山山脉南麓新疆库车县城以北60公里左右的山区,这里的风蚀雅丹地貌完全可以和流水侵蚀的丹霞地貌争奇斗艳。庞大的红色山体群形成于中生代的白垩纪,经亿万年的风剥雨蚀,洪流冲刷,形成纵横交错、层叠有序的垅脊与沟槽,远看如诗如画、仙天琼阁;近瞧若人似物、如梦似幻、惟妙惟肖、神韵万端,令人有鬼斧神工、奇景天成之慨叹。山体呈红色,原海底的岩石由于造山运动而形成的直立单斜岩石组成了层层叠叠的构造足迹,分外壮观,与附近不同色彩的山体错落有致、交相辉映。天山神秘大峡谷、红山石林和国道两侧雅丹地貌是著名