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Foraminiferal and calcareous nannoplankton bioevents and changes at the Late Cretaceous–earliest Paleogene transition in the northern margin of Tethys (Hyżne section, Polish Carpathians)
Geological Quarterly ( IF 0.9 ) Pub Date : 2020-09-11 , DOI: 10.7306/gq.1536
Elzbieta Katarzyna Machaniec, Oliwia Kowalczewska, Małgorzata Jugowiec, M. Adam Gasiński, Alfred Uchman

Foraminifera and calcareous nannoplankton from the Cretaceous–Paleogene (K-Pg) transition in the Hyżne section (Outer Carpathians, south-eastern Poland) show a relatively complete biostratigraphic record. Despite the absence of the Pa Zone in turbiditic deposits of the Polish Carpathians, the planktonic foraminiferal zones of the Late Cretaceous–Early Paleogene interval are well defined, including (1) the late Maastrichtian Abathomphalus mayaroensis Zone and its equivalents, (2) the earliest Danian Guembelitria cretacea second bloom Zone (P0 Zone), and (3) the top of the early Danian Parasubbotina cf. pseudobulloides (P1a) Zone. The foraminiferal events recorded in the studied section at the K-Pg transition are stratigraphically important. They include: (1) the interval with A. mayaroensis occurrence, (2) the interval with gradual disappearance of planktonic foraminifera from the most complex K-strategy forms, through the less specialized species to the large Heterohelicidae turnovers, and (3) the G. cretacea first and second blooms. Furthermore, the bloom of the opportunistic, benthic Bolivinita sp., the size reduction event, and the dissolution of the tests of the planktonic foraminifera are recorded. The K-Pg interval bioevents can be useful for better stratigraphic resolution of the flysch deposits of the Outer Carpathians. The nannoplankton event is represented by the appearance of Cruciplacolithus primus, which marks the onset of the return to more stable environmental conditions after the perturbations at the K-Pg boundary. The K-Pg boundary occurs within dark grey marly mudstones, above the upper boundary of the G. cretacea first bloom, and above the highest occurrence of the agglutinated foraminifera Goesella rugosa, at the top of the nannofossil CC 26 Zone, and below the deep-water agglutinated foraminifera (DWAF) dominance. The foraminiferal assemblages derive from different bathymetric zones corresponding to (1) the upper bathyal zone in the late Campanian (nannoplankton CC 22 Zone) and early late Maastrichtian (A. mayaroensis Zone), (2) the shelf margin in the latest late Maastrichtian (CC 26 nannoplankton Zone, G. cretacea first bloom), (3) the shelf margin in the earliest Danian (G. cretacea second bloom, NP1/2 Zone), and (4) the middle–lower bathyal depth, below a local foraminiferal lysocline and above CCD, in the latest early Danian (P. pseudobulloides Zone). As the foraminifera could have been redeposited by turbiditic currents, they do not necessarily show real bathymetric changes in the area of deposition. Such changes have not been observed in sedimentary features of the studied deposits. Foraminiferal and nannoplankton assemblages are typical of the “transitional zone” between the Tethyan and Boreal domains

 



中文翻译:

特提斯北部边缘白垩纪晚期至古近纪过渡时期的有孔虫和钙质纳米浮游生物活动和变化(波兰喀尔巴阡山脉的海涅剖面)

Hyżne断面(外喀尔巴阡,波兰东南部)的白垩纪-古近纪(K-Pg)过渡带孔虫和钙质纳米浮游生物显示出相对完整的生物地层记录。尽管在波兰喀尔巴阡山脉的浊积沉积物中没有Pa带,但是白垩纪晚期至古近纪间隔的浮游有孔虫带区却很明确,包括(1)晚马斯特里赫特的马兜铃亚马孙区及其等同物,(2)最早的大年Guembelitria cretacea第二布隆区(P0区),和(3)初期大年的顶部Parasubbotina比照 假鳞茎(P1a)区域。在研究剖面中记录的有孔虫事件在K-Pg跃迁上具有重要的地层学意义。它们包括:(1)玛雅曲霉发生的时间间隔;(2)浮游有孔虫从最复杂的K策略形式,通过较不专业的物种到大型异虫科的周转逐渐消失的时间间隔,以及(3)G. cretacea第一和第二花。此外,机会主义底栖玻利维尼塔的绽放记录了浮游有孔虫的大小,事件的大小和消散情况。K-Pg间隔生物事件可能有助于更好地层解析外喀尔巴阡山脉的复理沉积物。浮游生物事件以Cruplacolacolithus primus的出现为代表,这标志着在K-Pg边界发生扰动后,恢复到更稳定的环境条件的开始。K-Pg边界发生在深灰色的马利泥岩中,在白垩纪白垩纪首次开花的上边界上方,并且在凝集的有孔虫Goesella rugosa的最高出现位置上方,位于南化石CC 26区的顶部,而在深水凝集的有孔虫(DWAF)优势之下。有孔虫组合来自不同的测深区,这些测深区对应于(1)Campanian晚期(nannoplankton CC 22区)和Maastrichtian早期(A. mayaroensis区)的上层海底带,(2)Maastrichtian晚期( CC 26 nannoplankton区,白垩纪第一开花,(3)最早的达尼安(白垩纪第二开花,NP1 / 2区域)的架缘,和(4)中下部的深水底,在局部有孔虫之下丹参(P. pseudobulloides)的最新溶血碱和CCD以上区)。由于有孔虫本来可以通过湍流重新沉积,所以它们不一定在沉积区域内显示出真实的测深变化。研究的沉积物的沉积特征尚未观察到这种变化。有孔虫和纳米浮游生物的组合是特提斯和北部地区之间“过渡带”的典型特征

 

更新日期:2020-09-11
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