Climate forcing by iron fertilization from repeated ignimbrite eruptions: The icehouse–silicic large igneous province (SLIP) hypothesis

Abstract

During middle Eocene to middle Miocene time, development of the Cenozoic icehouse was coincident with a prolonged episode of explosive silicic volcanism, the ignimbrite fl are-up of southwestern North America. We present geochronologic and biogeochemical data suggesting that, prior to the establishment of full glacial conditions with attendant increased eolian dust emission and oceanic upwelling, iron fertilization by great volumes of silicic volcanic ash was an effective climatic forcing mechanism that helped to establish the Cenozoic icehouse. Most Phanerozoic cool-climate episodes were coeval with major explosive volcanism in silicic large igneous provinces, suggesting a common link between these phenomena.

Natural iron fertilization by the Eyjafjallajökull volcanic eruption

“…Volcanic ash emissions and subsequent aerosol deposition to the surface ocean have also frequently been implicated as a source of Fe [Duggen et al, 2010;Frogner et al, 2001;Sarmiento, 1993;Watson, 1997]. Increased productivity in both the modern [Langmann et al, 2010] and paleo oceans [Cather et al, 2009] has been linked to volcanism; however, direct observations of ash deposition and biogeochemical responses are scarce due to the intermittent and unpredictable nature of events. Nevertheless, observed decreases in atmospheric CO 2 following the large eruptions of Agung (1963) and Pinatubo (1991) have been interpreted in terms of the fertilizing effects of ash-derived Fe on ocean productivity [Cather et al, 2009;Sarmiento, 1993;Watson, 1997].…”

“…Increased productivity in both the modern [Langmann et al, 2010] and paleo oceans [Cather et al, 2009] has been linked to volcanism; however, direct observations of ash deposition and biogeochemical responses are scarce due to the intermittent and unpredictable nature of events. Nevertheless, observed decreases in atmospheric CO 2 following the large eruptions of Agung (1963) and Pinatubo (1991) have been interpreted in terms of the fertilizing effects of ash-derived Fe on ocean productivity [Cather et al, 2009;Sarmiento, 1993;Watson, 1997]. More recently, ocean color satellite observations provided evidence for enhanced phytoplankton growth in the HNLC Northeast Pacific following the eruption of the Kasatochi Volcano in 2008 [Hamme et al, 2010;Langmann et al, 2010] and in the low-nutrient low-chlorophyll North Pacific following the Anatahan eruption in 2003 [Lin et al, 2011].…”

Triggers of Permo-Triassic boundary mass extinction in South China: The Siberian Traps or Paleo-Tethys ignimbrite flare-up?

“…Major ignimbrites have volumes of 10 2 -10 4 km 3 in American Andes. Ultraplinian eruption columns and coignimbrite ash clouds are commonly tens of kilometers in height and can inject large volumes of volcanic ash into the stratosphere, where it could persist for years and distribute in a hemispherical or global scale (Cather et al, 2009). Ultraplinian-type eruptions of felsic volcanoes at multiple sites in swarm may have driven severe environmental changes in the biosphere through volcanic hazards; e.g., toxic gas emissions, developing dust/aerosol screens in the stratosphere (blocking sunlight), and pouring acid rain.…”

Epithermal mineralization controlled by synextensional magmatism in the Guazapares Mining District of the Sierra Madre Occidental silicic large igneous province, Mexico

“…The Sierra Madre Occidental silicic large igneous province is considered part of the extensive mid-Cenozoic ignimbrite flare-up that affected much of the southwestern North American Cordillera from the Middle Eocene to Late Miocene (e.g., Coney, 1978;Armstrong and Ward, 1991;Ferrari et al, 2002;Lipman, 2007;Cather et al, 2009;Henry et al, 2010;Best et al, 2013). The Sierra Madre Occidental trends for~1200 km southwest from the U.S.eMexico border to the Trans-Mexican Volcanic Belt (Fig.…”

“…The Lower Volcanic Complex is inferred to underlie most of the Upper Volcanic Supergroup (Aguirre-Díaz and McDowell, 1991;Ferrari et al, 2007), which is composed mainly of silicic ignimbrites, lavas, and intrusions (McDowell and Keizer, 1977;McDowell and Clabaugh, 1979;McDowell, 1991, 1993;Ferrari et al, 2002Ferrari et al, , 2007McDowell, 2007). The rocks of the Upper Volcanic Supergroup represent the products of episodic large-volume silicic large igneous province magmatism during the mid-Cenozoic ignimbrite flare-up that affected much of the southwestern North American Cordillera from the Middle Eocene to Late Miocene (e.g., McDowell and Keizer, 1977;Ferrari et al, 2007;Lipman, 2007;Cather et al, 2009;Henry et al, 2010;Best et al, 2013), with major ignimbrite eruptive pulses during the Eocene (ca. 46e42 Ma), Early Oligocene (ca.…”