First record of the Early Toarcian Oceanic Anoxic Event from the Southern Hemisphere, Neuquén Basin, Argentina

The first record of the Early Toarcian Oceanic Anoxic Event (c. 183 Ma) from the Southern Hemisphere is described from the Neuquén Basin, Argentina, identified chemostratigraphically on
the basis of a relative increase in marine organic carbon and a characteristic negative carbon-isotope excursion (δ13Corg) in bulk rock and fossil wood. The negative excursion of −6‰ in bulk organic carbon (falling to −31.3‰) crosses the boundary
of the tenuicostatum–hoelderi Andean ammonite Zones, equivalent to the tenuicostatum–falciferum/serpentinum zones of Europe. These data indicate that the Early Toarcian Oceanic Anoxic Event was a global phenomenon.

本文描述了来自阿根廷纽夸恩盆地的早托尔阶海洋缺氧事件（约183百万年前）的首个记录，该事件在南半球得以识别。这一发现基于海洋有机碳的相对增加以及岩石和化石木材中特有的负碳同位素异常（δ13Corg）。在总有机碳中，负异常值达到−6‰（降至−31.3‰），横跨了tenuicostatum-hoelderi安第斯地区菊石带，相当于欧洲的tenuicostatum-falciferum/serpentinum带。这些数据表明，早托尔阶海洋缺氧事件是一种全球性的现象。