气候变化领域集成服务门户(CCPortal): Enhanced upwelling and phosphorite formation in the northeastern Pacific during the late Oligocene: Depositional mechanisms, environmental conditions, and the impact of glacio-eustacy

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DOI	10.1130/B32061.1
	Enhanced upwelling and phosphorite formation in the northeastern Pacific during the late Oligocene: Depositional mechanisms, environmental conditions, and the impact of glacio-eustacy
	Schöllhorn I.; Houben A.; Gertsch B.; Adatte T.; Alexey U.; de Kaenel E.; Spangenberg J.E.; Janssen N.; Schwennicke T.; Föllmi K.B.
发表日期	2020
ISSN	167606
起始页码	687
结束页码	709
卷号	132 期号:2021-03-04
英文摘要	The late Oligocene-early Miocene interval records a discernable episode of phosphorite formation, which is considered as the first of four main phosphogenic episodes during the late early and late Cenozoic. In order to better constrain the processes leading to widespread phosphorite formation we present new radiometric, geochemical, palynological, and sedimentological data from a drill core of the Roca Fosforica Mexicana phosphorite mine at San Juan de la Costa, Baja California Sur (Mexico). In this region, phosphogenesis was enabled by the combination of high productivity and low sediment-accumulation rates due to enhanced upwelling and low detrital input related to regionally dry climate conditions. Phosphatic particles were formed in a shallow and well-oxygenated setting, subsequently concentrated by winnowing, and transported by gravity currents, which were mostly triggered by seismic activity. Following their deposition in a deeper and less well oxygenated setting pervasive phosphogenesis contributed to cementing the accumulated phosphatic grains. Correlation with global paleoclimate records suggests that this phosphogenic episode was linked to the expansion of the Antarctic ice sheet. Glacial weathering and the establishment of large-amplitude glacio-eustatic variations enhanced phosphorus supply on a global scale. Both glacial and interglacial phases participated in enhancing primary productivity in oceans, increasing the phosphorus flux into sediments, and favoring phosphogenesis, with glaciation being the prime cause. In addition, radiometric ages obtained in this study (28.62, 28.1, 27.19, 27.08, and 26.94 Ma) indicate that the onset of the late Oligocene-early Miocene phosphogenic episode was diachronous on a global scale with 2-3 m.y. older ages in the eastern Pacific in comparison to the Mediterranean and central Atlantic. This delay is explained by regional differences in paleoenvironmental and paleoceanographic conditions. © 2019 Geological Society of America.
语种	英语
来源期刊	Bulletin of the Geological Society of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/184810
作者单位	Institute of Earth Sciences, University of Lausanne, Géopolis, Lausanne, 1015, Switzerland; Geological Survey of the Netherlands, Netherlands Organization for applied scientific research, Princetonlaan 6, Utrecht, 3584 CB, Netherlands; Swiss National Science Foundation, Wildhainweg 3, Berne, 3001, Switzerland; DeKaenel Paleo-Research, Mont-sur-Rolle, 1185, Switzerland; Institute of Earth Surface Dynamics, University of Lausanne, Géopolis, Lausanne, 1015, Switzerland; Academic Department of Earth Sciences, Autonomous University of Baja California Sur, Carretera al sur km 5.5, La Paz, Baja California Sur, 23080, Mexico
推荐引用方式 GB/T 7714	Schöllhorn I.,Houben A.,Gertsch B.,et al. Enhanced upwelling and phosphorite formation in the northeastern Pacific during the late Oligocene: Depositional mechanisms, environmental conditions, and the impact of glacio-eustacy[J],2020,132(2021-03-04).
APA	Schöllhorn I..,Houben A..,Gertsch B..,Adatte T..,Alexey U..,...&Föllmi K.B..(2020).Enhanced upwelling and phosphorite formation in the northeastern Pacific during the late Oligocene: Depositional mechanisms, environmental conditions, and the impact of glacio-eustacy.Bulletin of the Geological Society of America,132(2021-03-04).
MLA	Schöllhorn I.,et al."Enhanced upwelling and phosphorite formation in the northeastern Pacific during the late Oligocene: Depositional mechanisms, environmental conditions, and the impact of glacio-eustacy".Bulletin of the Geological Society of America 132.2021-03-04(2020).