Enhanced coastal paleoproductivity and nutrient supply in Upper Egypt during the Paleocene/Eocene Thermal Maximum (PETM): Mineralogical and geochemical evidence

The spread of marine anoxia on the northern Tethys margin during the Paleocene-Eocene Thermal Maximum

“…The importance of continental erosion and weathering on the availability of nutrients is not a phenomenon confined to the northern Peri‐Tethys. There are numerous examples from locations such as New Zealand [ Crouch et al , ; Hollis et al , ; Nicolo et al , ], the New Jersey shelf [ Gibbs et al , ; John et al , ; Sluijs and Brinkhuis , ], the Arctic Ocean [ Sluijs et al , ; Stein et al , ; Harding et al , ], the southern Tethys Ocean [ Speijer and Schmitz , ; Soliman et al , ; Schulte et al , ], and Tanzania [ Handley et al , ] where terrestrial sediment accumulation rates and nutrient availability increased during the PETM. Enhanced rates of continental weathering are likely to have been a global feature of the PETM [ Ravizza et al , ].…”

“…One question that can be addressed by studying the PETM is how marine ecosystems and biogeochemical cycles respond to changes in dissolved oxygen concentrations [O 2 ] in seawater. An increasing number of observations indicate that [O 2 ] decreased on a global scale during the PETM [ Dickson et al , ] and at individual locations in shallow marine (<1000 m) [e.g., Canudo et al , ; Speijer et al , ; Bolle et al , ; Gavrilov et al , ; Sluijs et al , , ; Soliman , , Soliman et al ., ; Lippert and Zachos , ; Nicolo et al , ; Schulte et al , ; Khozyem et al , ] and at deep marine (>1000 m) [e.g., Bralower et al , ; Thomas , ; Kaiho et al , ; Colisimo et al , ; Chun et al , ] locations. Dissolved [O 2 ] reflects the balance between the remineralization of sinking organic matter and oxygen ventilation by ocean currents, with preformed [O 2 ] set by seawater temperature at the air‐sea boundary [e.g., Keeling et al , ].…”

“…Extensive efforts have been made to understand the origin and nature of the Tethyan C org ‐enriched deposits, and in particular, the unique paleoceanographic conditions that led to their preservation in the geological record. Much of this effort has been directed at locations found on the southern Tethyan margin in present‐day North Africa and the Middle East (Figure ), which form a depth transect extending from upper neritic (<50 m) to lower bathyal (>600 m) water depths [e.g., Schmitz et al , , ; Speijer et al , ; Speijer and Schmitz , ; Speijer and Morsi , ; Speijer and Wagner , ; Dupuis et al , ; Knox et al , ; Soliman , , Soliman et al ., ]. At these southern locations, studies have suggested that the C org ‐rich PETM deposits formed due to a combination of low‐[O 2 ] waters that upwelled along the continental margin, and high rates of marine productivity stimulated by nutrients recycled from deeper water masses and also delivered by high rates of continental erosion and weathering [ Schmitz et al , ; Charisi and Schmitz , ; Speijer and Schmitz , ; Huber and Sloan , ; Soliman et al , ; Schulte et al , ; Stassen et al , ; Khozyem et al , ].…”

Expanded oxygen minimum zones during the late Paleocene‐early Eocene: Hints from multiproxy comparison and ocean modeling

“…I/Ca data on planktonic foraminifera indicate expanded OMZs in the upper water column of major oceans [Zhou et al, 2014], which may be related to the increase of the temperature-dependent remineralization rate, thus more intense O 2 depletion at shallow depths [e.g., John et al, 2014]. Bottom water oxygen depletion occurred in marginal basins of the Tethys and peri-Tethys [e.g., Canudo et al, 1995;Speijer, 1997;Bolle et al, 2000;Gavrilov et al, 2003;Soliman et al, 2011;Dickson et al, 2014;Giusberti et al, 2016], along continental margins such as New Jersey [Lippert and Zachos, 2007;Stassen et al, 2012Stassen et al, , 2015 and New Zealand [Nicolo et al, 2010], and in the Arctic Ocean [Sluijs et al, 2006]. However, evidence for oxygenation changes in the deep open ocean is less clear.…”

Variation of minerals and clay minerals recorded in the Neo-Tethys (central Turkey): new evidence of climatic changes during the middle Eocene

“…A divergence between the d 18 O curves of the shallow-and deep-water dwelling planktonic foraminifera after the event suggests a more stratified water column in the Neo-Tethys. ROBERT; KENNET, 1994;KAIKO et al, 1996;GAWENDA et al, 1999;GIBSON;BYBELL;MASON, 2000;ERNST et al, 2006;SCHULTE;SCHEIBNER;SPEIJER, 2011;SOLIMAN et al, 2011;JOHN et al, 2012;BORNEMANN et al, 2014;PUJALTE;BACETA;SCHMITZ, 2015;CHEN et al, 2016;KEMP et al, 2016). The EECO proxies were identified in the western Pyrenees and in China, also with an increase in kaolinite, however towards the end of the period, dryer conditions may have prevailed ( WANG et al, 2013a;PAYROS et al, 2015).…”