The Kačák Event is one of the several prominent Devonian climatic and biotic perturbations with a supra-regional to global extent. Its record can be traced in the litho- and biostratigraphy of uppermost Eifelian-lowermost Givetian strata and with multiple geochemical and geophysical proxies. In southwest Iberia, within southwestern Ossa-Morena Zone domains, there are rare, scattered Early-Middle Devonian limestone occurrences. One of these occurrences—the Odivelas Limestone type locality—is revisited in terms of conodont biostratigraphy and palynology and the results compared with previous data on reef macrofauna and magnetic susceptibility stratigraphy. The new data show that this locality is probably within the Polygnathus hemiansatus zone, i.e. of the earliest Givetian age. The palynological content of a ca. 2 m of black, organic-rich, fine grained limestone section is dominated, in varied proportions, by amorphous organic matter, putative fungal hyphae, and prasinophycean algae. The results are interpreted as an indication of high organic productivity and deposition in hypoxic to anoxic settings and probable biotic crisis, in both marine and terrestrial realms, connected with the Middle Devonian Kačák Event. The similarity of this record with other Devonian events is discussed.

Kačák事件是泥盆纪几个主要的气候和生物扰动之一，涉及全球范围以上。它的记录可以追溯到最上层的伊非利亚-最下层的吉夫田地层的岩石和生物地层，并具有多种地球化学和地球物理的代理。在伊比利亚西南部的Ossa-Morena西南部区域内，稀有零星的早中中期泥盆纪石灰岩发生。在牙形石生物地层学和孢粉学方面重新审视了其中一种情况-Odivelas石灰岩类型的局部性，并将结果与​​以前关于珊瑚礁大型动物区系和磁化率地层学的数据进行了比较。新数据表明该地区可能在Polygnathus hemiansatus内区，即最早的吉夫田时代。一个ca的孢粉含量。黑色的，富含有机物的细颗粒石灰岩段2 m，以不同比例以无定形有机物，推定的真菌菌丝和藻类藻类藻类为主。结果被解释为与中泥盆世Kačák事件有关的海洋和陆地领域中高有机生产力和缺氧至缺氧环境下的沉积以及可能的生物危机。讨论了该记录与泥盆纪其他事件的相似性。