豫西下二叠统太原组遗迹化石与古氧相的响应特征*
Responding characteristics between ichnofossils and palaeo-oxygen facies in the Lower Permian Taiyuan Formation of western Henan Province

基于对豫西禹州和焦作地区下二叠统太原组中的遗迹化石组成与产状特征的研究,以及对不同颜色Zoophycos潜穴充填物中碳氧同位素和微量元素含量的测试分析,取得成果如下: (1)灰白色充填物中δ¹³C值较低,主要介于-2‰~-4‰之间;灰色充填物中δ¹³C值大多在-0.8‰~-2‰之间。二者的V/(V+Ni)值均小于0.46,Ce/La值均小于1.5。反映其为富氧相,即氧化环境。(2)红褐色充填物中δ¹³C值一般在-0.2‰~-0.9‰之间,V/(V+Ni)值大于0.46,反映其为贫氧相,即弱还原环境。(3)黑色充填物中δ¹³C值最高,多数在0.2‰~1.6‰之间,Ce/La值大于1.8,反映其为厌氧相,即还原环境。综合分析上述特征,提出了3种古氧相(富氧相、贫氧相和厌氧相)的遗迹化石响应关系及其形成的沉积背景模式。这一研究成果可为精细分析豫西下二叠统太原组碳酸盐岩的沉积环境演变规律提供直观的生物遗迹识别标志。
On the basis of the composition and appearance study of the ichnofossils in the Lower Permian Taiyuan Formation of Yuzhou and Jiaozuo area of western Henan Province,as well as tests and analyses of the δ¹³C,δ¹⁸O and trace elements in the four kinds of different color fillings of Zoophycos burrows,the results were obtained as follows: (1)The δ¹³C value ranges between -2‰ and -4‰ in the off-white fillings and between -0.8‰ and -2‰ in the gray fillings. In these two kinds of color fillings,the V/(V+Ni) value is less than 0.46,and the Ce/La value is less than 1.5. These data indicate that the sedimentary environment is characterized with an aerobic condition. (2)The δ¹³C value ranges generally between -0.2‰ and -0.9‰,and the V/(V+Ni)value is more than 0.46 in the brown fillings,which reflect a dysaerobic sedimentary environment. (3)The δ¹³C value ranges mostly between 0.2‰ and 1.6‰,and the Ce/La value is more than 1.8 in the black fillings,which reflect an anaerobic sedimentary environment. Based on the comprehensive analysis of above mentioned characteristics,we suggested the responding characteristics model between the three kinds of palaeo-oxygen facies(aerobic,dysaerobic and anaerobic facies)and ichnofossils and their sedimentary setting. This research result can provide some intuitional ichnofossil marks to identify sedimentary environment changes in the