DOI: 10.1016/j.palaeo.2017.08.017
论文题名: Paleoenvironmental evolution in a high-stressed cold-seep system (Vicchio Marls, Miocene, northern Apennines, Italy)
作者: Grillenzoni C. ; Monegatti P. ; Turco E. ; Conti S. ; Fioroni C. ; Fontana D. ; Salocchi A.C.
刊名: Palaeogeography, Palaeoclimatology, Palaeoecology
ISSN: 0031-0182
出版年: 2017
语种: 英语
英文关键词: Benthic foraminifera
; Middle Miocene
; Molluscs
; Paleoecology
; Seep-carbonates
; Stable isotopes
英文摘要: Excellent exposures of Miocene seep-carbonates enclosed in marine marly sediments (Vicchio outcrops in the northern Apennines, Italy) offer the opportunity to highlight the evolution of a fossil seep ecosystem and the response of benthic communities to high-stressed environmental conditions. For this purpose, seep-related facies and molluscs within carbonate bodies have been studied, coupled with benthic foraminiferal assemblages and carbon and oxygen isotopes in the enclosing marls. The integrated planktonic foraminiferal and calcareous nannofossil biostratigraphy has allowed us to constrain the seepage within well-calibrated bioevents and to stress the relationships with paleoclimatic and paleoceanographic variations during the middle Miocene in the Mediterranean area. Our biostratigraphic data indicate that the onset of the seepage approximates the Mi3b cooling event (13.82Ma) and the seepage system lasts for 400kyr. The evolution of the Vicchio cold-seep system passes through four phases: (1) The onset of the seepage, characterized by a pervasive flow of methane-rich fluids, is inferred by δ13C depletion of marly sediments and by prevailing benthic foraminifera indicative of suboxic conditions at the sea-floor. (2) The methane flow becomes focused causing the precipitation of wide pinnacle-like carbonate bodies which contain giants lucinids. Enclosing marls indicate well-oxygenated conditions, possibly enhanced by paleoceanographic variations connected to the Mi3b cooling event. (3) The appearance of the vesicomyid Christineconcha cf. C. regab and the absence of lucinids in seep-carbonates suggest stable methane-rich fluid emissions; higher flow rates locally favoured the flourishment of bacterial mats. Benthic foraminifera show abundance peaks of organic matter depending taxa. (4) The reduced intensity of methane-rich fluid flows favours the precipitation of stratiform carbonate bodies along strike; the macrofauna is characterized by the presence of both Vesicomyidae and giant lucinids. Foraminiferal assemblages in the enclosing marls indicate the restoration of well-oxygenated conditions. © 2017 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/68154
Appears in Collections: 过去全球变化的重建
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作者单位: Dipartimento di Scienze Chimiche e Geologiche, Università di Modena e Reggio Emilia, Via G. Campi 103, 41125 Modena, Italy; Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale, Università di Parma, Parco Area delle Scienze 157/A, 43124 Parma, Italy
Recommended Citation:
Grillenzoni C.,Monegatti P.,Turco E.,et al. Paleoenvironmental evolution in a high-stressed cold-seep system (Vicchio Marls, Miocene, northern Apennines, Italy)[J]. Palaeogeography, Palaeoclimatology, Palaeoecology,2017-01-01