S. Distefano, F. Gamberi, N. Baldassini, A. Stefano
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(=S2) by an erosional surface, identified with the offshore TU (=Tortonian Unconformity) horizon, passing upward to the Vallone della Forbice Mb. (=S3) through a gradual, concordant boundary (Upper Tortonian Boundary=UTB). Capo Grecale and Vallone della Forbice Mbs., and thus the S2 and S3 units, represent the syn-rift deposits, recording the Late Miocene extensional tectonic activity. The effects of the strong erosional phase connected with the Mediterranean Salinity Crisis of Messinian age, are visible in all the seismic lines coinciding with a high impedance irregular surface (MH=Messinian Horizon), above which a further seismic unit (S4) develops. This latter, constituted by reflections onlapping the substratum, in the lower part, and prograding in the upper one, does not find an onshore correspondence, but has been attributed to the post-Messinian (Zanclean) transgression, followed by the subsequent regressive phase (Piacenzian-Gelasian). The uppermost seismic unit (S5), unconformably covering the older substratum, through the Early Pleistocene Unconformity (=EPU horizon) corresponds to the Pleistocene-Holocene onshore deposits. The seabed (top of S5) shows regular morphologies in the southern sector, while in the northern sector it is cut by erosive channels connected to strong streams on the bottom.From a structural point of view, the southern sector recorded an extensional tectonic phase, giving rise to normal faults involving units from S1 to S3, sutured by the MH and the overlain deposits. In the northern sector, the tectonic phase continued until the Pliocene, also involving the S4 unit.The reconstructed tectonic setting well fits the more general setting of the Sicily Channel Rift Zone, where main WNW-ESE faults were active during the Late Miocene and until the Pliocene age, generating small depositional areas, bounded by second-order NNW- SSE normal faults.","PeriodicalId":49317,"journal":{"name":"Italian Journal of Geosciences","volume":" ","pages":""},"PeriodicalIF":1.0000,"publicationDate":"2019-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3301/IJG.2019.17","citationCount":"6","resultStr":"{\"title\":\"Neogene stratigraphic evolution of a tectonically controlled continental shelf: the example of the Lampedusa island\",\"authors\":\"S. Distefano, F. Gamberi, N. Baldassini, A. 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引用次数: 6
摘要
兰佩杜萨岛位于西西里海峡和整个地中海地区的中心位置,是一个关键地区。通过采集和解释16条“sparker系统”地震线,可以精细地重建兰佩杜萨大陆架的沉积结构及其构造演化的详细时间,为影响西西里海峡这一地区的地球动力学过程做出贡献。海上剖面显示了五个地震相,并与陆上序列进行了比较。较老的地震单元(S1)与裂谷前的Cala Pisana Mb相关。兰佩杜萨组,由上覆Capo Grecale Mb分隔。(=S2)被侵蚀面侵蚀,与近海TU(=Tortonian不整合面)层位一致,向上延伸至Vallone della Forbice Mb。(=S3)穿过一个渐变的、一致的边界(上托托尼亚边界=UTB)。Capo Grecale和Vallone della Forbice Mbs。,S2和S3单元代表同裂谷矿床,记录了中新世晚期的伸展构造活动。在与高阻抗不规则表面(MH=墨西尼亚地平线)重合的所有地震线上,都可以看到与墨西尼亚时代地中海盐度危机有关的强侵蚀相的影响,在该不规则表面之上形成了另一个地震单元(S4)。后者由下部覆盖下层的反射和上部的进积组成,没有发现陆上对应关系,但被归因于后梅西尼亚(赞clean)海侵,随后是随后的海退阶段(皮亚琴齐亚-盖拉西亚)。最上面的地震单元(S5)不整合地覆盖着较老的下地层,穿过早更新世不整合面(=EPU层位),对应于更新世全新世陆上沉积物。海床(S5顶部)在南部区域显示出规则的形态,而在北部区域,海床被与底部强流相连的侵蚀通道切割。从结构的角度来看,南部记录了一个伸展构造阶段,产生了涉及S1至S3单元的正断层,由MH和上覆矿床缝合。在北部,构造阶段一直持续到上新世,也涉及S4单元。重建的构造环境非常适合西西里海峡裂谷带的更为普遍的环境,在中新世晚期和上新世之前,那里的主要WNW-ESE断层一直很活跃,形成了以二阶NNW-SSE正断层为界的小沉积区。
Neogene stratigraphic evolution of a tectonically controlled continental shelf: the example of the Lampedusa island
Lampedusa Island represents a key-area due to its central position within the Sicily Channel and the whole Mediterranean region. The acquisition and interpretation of sixteen “sparker-system” seismic lines allowed a refined reconstruction of the sedimentary architecture of the Lampedusa continental shelf and the detailed timing of its tectonic evolution, providing a contribution to the geodynamic processes affecting this sector of the Sicily Channel.The offshore profiles show five seismic facies, which have been compared with the onshore succession. The older seismic unit (S1) was correlated with the pre-rift Cala Pisana Mb. of the Lampedusa Fm., separated by the overlain Capo Grecale Mb. (=S2) by an erosional surface, identified with the offshore TU (=Tortonian Unconformity) horizon, passing upward to the Vallone della Forbice Mb. (=S3) through a gradual, concordant boundary (Upper Tortonian Boundary=UTB). Capo Grecale and Vallone della Forbice Mbs., and thus the S2 and S3 units, represent the syn-rift deposits, recording the Late Miocene extensional tectonic activity. The effects of the strong erosional phase connected with the Mediterranean Salinity Crisis of Messinian age, are visible in all the seismic lines coinciding with a high impedance irregular surface (MH=Messinian Horizon), above which a further seismic unit (S4) develops. This latter, constituted by reflections onlapping the substratum, in the lower part, and prograding in the upper one, does not find an onshore correspondence, but has been attributed to the post-Messinian (Zanclean) transgression, followed by the subsequent regressive phase (Piacenzian-Gelasian). The uppermost seismic unit (S5), unconformably covering the older substratum, through the Early Pleistocene Unconformity (=EPU horizon) corresponds to the Pleistocene-Holocene onshore deposits. The seabed (top of S5) shows regular morphologies in the southern sector, while in the northern sector it is cut by erosive channels connected to strong streams on the bottom.From a structural point of view, the southern sector recorded an extensional tectonic phase, giving rise to normal faults involving units from S1 to S3, sutured by the MH and the overlain deposits. In the northern sector, the tectonic phase continued until the Pliocene, also involving the S4 unit.The reconstructed tectonic setting well fits the more general setting of the Sicily Channel Rift Zone, where main WNW-ESE faults were active during the Late Miocene and until the Pliocene age, generating small depositional areas, bounded by second-order NNW- SSE normal faults.
期刊介绍:
The Italian Journal of Geosciences (born from the merging of the Bollettino della Società Geologica Italiana and the Bollettino del Servizio Geologico d''Italia) provides an international outlet for the publication of high-quality original research contributions in the broad field of the geosciences.
It publishes research papers, special short papers, review papers, discussion-and-replies for their rapid distribution to the international geosciences community.
The journal is firstly intended to call attention to the Italian territory and the adjacent areas for the exceptional role they play in the understanding of geological processes, in the development of modern geology and the Earth sciences in general.
The main focus of the journal is on the geology of Italy and the surrounding sedimentary basins and landmasses, and on their relationships with the Mediterranean geology and geodynamics. Nevertheless, manuscripts on process-oriented and regional studies concerning any other area of the World are also considered for publication.
Papers on structural geology, stratigraphy, sedimentology, basin analysis, paleontology, ecosystems, paleoceanography, paleoclimatology, planetary sciences, geomorphology, volcanology, mineralogy, geochemistry, petrology, geophysics, geodynamics, hydrogeology, geohazards, marine and engineering geology, modelling of geological process, history of geology, the conservation of the geological heritage, and all related applied sciences are welcome.