Organic facies of the early Albian Niveau Paquier, a key black shales horizon of the Marnes Bleues formation in the Vocontian Trough (Subalpine Ranges, SE France)
Organic facies of the early Albian Niveau Paquier, a key black shales horizon of the Marnes Bleues formation in the Vocontian Trough (Subalpine Ranges, SE France)
复制标题
早期 Albian Niveau Paquier 的有机相，是 Vocontian 海槽（法国东南部亚高山山脉）Marnes Bleues 地层的关键黑色页岩层位
DOI：
10.1016/0031-0182(91)90162-k
复制
发表时间：
1991
期刊：
影响因子：
--
通讯作者：
G. Gorin
中科院分区：
文献类型：
--
作者：
N. Tribovillard;G. Gorin
marnes Bleues组沉积在Aptian-Albian时期的Vocontian海槽的中央半远洋部分。它含有几个层次的黑色页岩，其特点是含有丰富的大陆和海洋有机质，以及在浮游和底栖有孔虫含量的一些质量和数量的变化。在这里，我们集中讨论这些视野中最引人注目的一个：尼沃·帕奎尔（Niveau Paquier）（早期阿尔比亚）。Niveau Paquier具有层状纸页岩相。它的厚度从几分米到5米不等，可以在阿尔卑斯特提斯的大部分地区找到。它是马内斯蓝色地层中有机物最丰富的地层之一。它显示了海洋（藻囊、藻类、有孔虫衬层、无定形有机物或AOM）和陆地来源（惰质组、镜质组、角质组、孢子和花粉）的有机含量的微妙波动。Niveau Paquier的许多特征（岩性、微型动物、有机质、存在常驻缺氧动物群等）表明在厌氧、缺氧和有氧条件之间频繁振荡。可以提出一个涉及水分层的微妙变化的模型：氧化还原电位不连续层或密度跃层的波动位置会影响表-中-浮游生物、浮游生物和表-内-底栖生物以及有机物（主要是AOM）的性质和保存。Niveau Paquier的有机参数（孢粉相和岩石评价数据）似乎记录了大约四个ca。十万年的循环。这些循环可能与气候变化有关，气候变化影响了向沃康先海槽提供粘土矿物、有机残留物和营养物的新兴陆地以及海洋环境的条件。这些变化似乎是在米兰科维奇频段。
The marnes Bleues Formation was deposited in the central, hemipelagic part of the Vocontian Trough during Aptian-Albian times. It contains several levels of black shales which are characterized by abundant organic matter of both continental and marine origin, as well as by some qualitative and quantitative variations in planktonic and benthic foraminifera contents. We concentrate here upon the most striking of these horizons: the Niveau Paquier (early Albian). The Niveau Paquier has a laminated, paper shale facies. Varying in thickness from a few decimeters to 5 m, it can be traced over a large part of the Alpine Tethys. It is one of the most organic-rich levels in the Marnes Bleues Formation. It displays a subtly fluctuating organic content of both marine (dinocysts, algae, foraminifera linings, amorphous organic matter or AOM) and terrestrial origins (inertinite, vitrinite, cutinite, spores and pollen). Many characteristics of the Niveau Paquier (lithology, microfauna, organic matter, presence of resident dysaerobic faunas, etc.) suggest frequent oscillations between anaerobic, dysaerobic and aerobic conditions. A model involving subtle modifications in the water stratification can be suggested: the fluctuating position of the redox-potential-discontinuity layer (RPD-layer) or of the pycnocline would have affected epi-meso-planktonic, nectonic and epi-endo-benthic life and the nature and preservation of organic matter (mainly of AOM). Organic parameters (palynofacies and Rock Eval data) of the Niveau Paquier seem to have recorded some four ca. 100,000-yr long cycles. These cycles may be related to climatic variations affecting both the emerged lands supplying the Vocontian Trough in clay minerals, organic residues and nutrients and the conditions in the marine milieu. These variations seem to be in the Milankovitch frequency band.