In 2013, Andra (French National Radioactive Waste Management Agency) drilled boreholes to the south-east of the Paris Basin, to characterise Aptian and Albian clayey formations, including the ‘Argiles à Plicatules’ Formation dated as early Aptian. One of these boreholes intersected this formation with an excellent recovery allowing detailed biostratigraphy (ammonites), sedimentology, clay mineralogy, isotope geochemistry (δ¹³C_org) and Rock-Eval analyses to be performed. The base of the formation corresponds to transgressive dark-grey silty clays with iron oolites and plant debris indicating a coastal environment evolving up-section to upper offshore environments. Higher in the succession, clays with less than 4% CaCO₃ and less than 0.8% of organic matter were deposited in lower offshore environments. The occurrence of ammonites can be used to draw a biostratigraphic scheme, and in particular, to recognise the deshayesi and furcata ammonite Zones.

The clay mineral assemblages are composed of illite and kaolinite associated with minor amounts of chlorite, vermiculite and smectite. The δ¹³C_org values range between −24 and −25‰ except in a particular interval characterised by a prominent negative excursion of about −3‰, that is recognised worldwide and precedes Oceanic Anoxic Event 1a (OAE1a). This interval is also characterised by an abundance of kaolinite and the absence of smectite suggesting an acceleration of the hydrological cycle and enhanced runoff and hydrolysing conditions over the emerged landmasses just before and during the onset of OAE1a. This climate change is consistent with isotope and palynological data indicating warm and humid climate conditions before and during the onset of OAE1a. Surprisingly, the interval corresponding to OAE1a is not significantly enriched in organic matter and its lithology is not different from the rest of the core suggesting that Tethyan anoxic water masses did not reach the relatively shallow epicontinental environments of the Paris Basin.

2013年，安德拉（法国国家放射性废物管理局）在巴黎盆地东南部钻了个钻孔，以表征阿普提安和阿尔比粘土地层的特征，其中包括早于阿普提安的“ ArgilesàPlicatules”地层。其中一个钻孔的相交具有优异的恢复允许详细生物地层（菊），沉积，粘土矿物学此形成，同位素地球化学（δ ¹³ Ç_组织）来执行和生油岩评价仪分析。地层的底部对应于海侵性的深灰色粉质黏土，带有铁质铁矿和植物碎屑，表明沿海环境从上到上逐渐演变为上层离岸环境。CaCO ₃含量低于4％的粘土含量较高不到0.8％的有机物沉积在较低的近海环境中。铵矿的出现可用于绘制生物地层学方案，尤其是用于识别脱沙es石和糠醛铵矿区。

粘土矿物组合由伊利石和高岭石以及少量的亚氯酸盐，ver石和蒙脱石组成。该δ ¹³ C ^_组织该值的范围介于-24至-25‰之间，除了在一个特定的区间内，该区间的特征在于约-3‰的显着负偏移，该偏移在全世界范围内公认并且发生在海洋缺氧事件1a（OAE1a）之前。该间隔期的特征还在于高岭石含量丰富而绿土含量不足，这表明在刚发生OAE1a之前和期间，出现的陆块上的水文循环加速，径流和水解条件增强。这种气候变化与表明OAE1a发生之前和期间温暖和潮湿的气候条件的同位素和古生物学数据一致。出奇，