New insights on the middle Givetian/middle Frasnian palynofloras from the Phyllite-Quartzite Formation in the Neves-Corvo mine region (Iberian Pyrite Belt, Portugal)

IF 0.7 Q4 PALEONTOLOGY

REVUE DE MICROPALEONTOLOGIE Pub Date : 2020-10-01 DOI:10.1016/j.revmic.2020.100447

Márcia Mendes , Zélia Pereira , João Xavier Matos , Luís Albardeiro , Igor Morais , Rita Solá , Rute Salgueiro , Nelson Pacheco , Vitor Araújo , Carlos Inverno , José Tomás Oliveira

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引用次数: 9

Abstract

A detailed palynostratigraphic study of two Somincor/Lundin Mining exploration drill holes intercepting the Phyllite-Quartzite (PQ) Formation in the geological basement of the Neves-Corvo mine region (Portuguese sector of the Iberian Pyrite Belt – IPB) allowed to first recognise the oldest ages for this formation in this region, ranging from midGivetian/midFrasnian (base unknown) to late Famennian. The TA Miospore Biozone (Cristatisporites triangulatus-Ancyrospora ancyrea) of middle Givetian age (Middle Devonian) was identified in NK30B-1 drill hole (Lombador North mine sector), whereas the BM Miospore Biozone (Verrucosisporites bulliferus-Lophozonotriletes media) and IV Miospore Biozone (based in the first occurrence of Rugospora bricei and Diducites cf. poljessicus) of middle Frasnian (Late Devonian) age were both recognised in drill hole SJ32 (Corvo-Semblana mine sector). The common presence of Early-Middle Devonian reworked spores, as well as similar inherited zircon ages may suggest that the lower PQ Formation age is not yet known.

At Neves-Corvo mine, the Volcano-Sedimentary Complex is deposited directly above the PQ basement, spanning different ages, pointing out two major unconformities, a VSC/upper and/or lower PQ sequences and an upper PQ/lower PQ sequences.

A palynostratigraphic correlation of the lowermost Phyllite-Quartzite Formation across the IPB is established. Phyllite-Quartzite Formation palynoassemblage of Neves-Corvo region is compared with lowermost PQ assemblages recovered in the NW sector of IPB (S. Francisco da Serra and Lousal-Caveira mine structures, Portugal) and in E sectors of the IPB in Spain (Gerena-El Garrobo section). The similar palynological record (also including the same reworked taxa signature) and ages obtained, suggests identical sedimentary provenance, close paleogeographic domain and temporal affinity throughout the lowermost IPB Phyllite-Quartzite Formation.

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Neves-Corvo矿区(伊比利亚黄铁矿带)百叶岩-石英岩组盖文纪中期/弗拉斯纪中期孢粉植物新认识

通过对Neves-Corvo矿区(伊比利亚黄铁矿带葡萄牙部分)地质基底中截取的两个Somincor/Lundin采矿勘探钻孔进行详细的孢球地层研究，首次确定了该地区该地层最古老的年龄，从givetian中期/ frasian中期(基地未知)到famenian晚期。NK30B-1钻孔(Lombador北矿区)发现了中泥盆世(中泥盆世)的TA微孢子生物带(Cristatisporites triangulatus-Ancyrospora anyrea)，而SJ32钻孔(Corvo-Semblana矿区)发现了中泥盆世(晚泥盆世)的BM微孢子生物带(Verrucosisporites bulliferus-Lophozonotriletes media)和IV微孢子生物带(基于Rugospora bricei和Diducites cfj . poljessicus的首次出现)。早-中泥盆世改造孢子的普遍存在，以及相似的继承锆石年龄，可能表明下PQ组年龄尚不清楚。Neves-Corvo矿的火山-沉积杂岩直接沉积在PQ基底的正上方，跨越不同的时代，指出了两个主要的不整合面，VSC/上和/或下PQ层序和上PQ/下PQ层序。建立了横跨IPB的最底层千层岩-石英岩组的孢粉地层对比。将Neves-Corvo地区的千层岩-石英岩组孢粉组合与IPB NW段(葡萄牙S. Francisco da Serra和Lousal-Caveira矿构造)和西班牙IPB E段(Gerena-El Garrobo段)最低PQ组合进行了比较。相似的孢粉记录(也包括相同的重新加工分类群特征)和年龄表明，在IPB最底层的千叶岩-石英岩组中，相同的沉积物源、紧密的古地理域和时间亲和性。

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来源期刊

REVUE DE MICROPALEONTOLOGIE PALEONTOLOGY-

CiteScore

2.50

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0.00%

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期刊介绍： La Revue de micropaléontologie publie 4 fois par an des articles de intérêt international, consacrés à tous les aspects de la micropaléontologie. Les textes, en anglais ou en français, sont des articles originaux, des résultats de recherche, des synthèses et mises au point, des comptes rendus de réunions scientifiques et des analyses de ouvrages. La revue se veut résolument ouverte à tous les aspects de la micropaléontologie en accueillant des travaux traitant de la systématique des microfossiles (et de leurs équivalents actuels), des bactéries aux microrestes de vertébrés, et de toutes leurs applications en sciences biologiques et géologiques.