Oxygen isotope analysis of the eyes of pelagic trilobites: Testing the application of sea temperature proxies for the Ordovician

Abstract

Oxygen isotope analysis of the eyes of pelagic trilobites: testing the application of sea temperature proxies for the Ordovician

A high-resolution record of early Paleozoic climate

“…Although the Svalbard sample array implies greater water/rock ratios than the Newfoundland array, both sample suites have much higher bulk δ 18 O compositions than would be expected under fully fluid-buffered equilibration at burial conditions. δ 18 O values of micritic samples from Svalbard are similar to those of ocular calcite in fossil trilobites from this section (40) and substantially different from those of adjacent vein-hosted calcite spar.…”

A Thermal Pulse Induced by a Permian Mantle Plume in the Tarim Basin, Northwest China: Constraints From Clumped Isotope Thermometry and In Situ Calcite U‐Pb Dating

“…Micrite matrix in marine limestones is commonly believed to record at least some geochemical properties of the ocean water from which it precipitated, and is a widely used archive for paleoclimate and paleoenvironmental reconstructions (Bartolini et al., 1999; Coimbra et al., 2009; Y. Gao et al., 2018; Guido et al., 2016; Kasemann et al., 2005; Martin et al., 2012; Rais et al., 2007). However, micrite can be chemically altered through recrystallization during burial and extensive recrystallization has been suggested to have occurred on Paleozoic carbonates (Bennett et al., 2018; Cummins et al., 2014; G. Gao & Land, 1991; Joachimski et al., 2004; Land & Lynch, 1996; Ryb & Eiler, 2018).…”

“…Gao et al, 2018;Guido et al, 2016;Kasemann et al, 2005;Martin et al, 2012;Rais et al, 2007). However, micrite can be chemically altered through recrystallization during burial and extensive recrystallization has been suggested to have occurred on Paleozoic carbonates (Bennett et al, 2018;Cummins et al, 2014;G. Gao & Land, 1991;Joachimski et al, 2004;Land & Lynch, 1996;.…”

Thermal and exhumation histories of the northern subalpine chains (Bauges and Bornes—France): Evidence from forward thermal modeling coupling clay mineral diagenesis, organic maturity and carbonate clumped isotope (Δ47) data

“…This Δ 47 dependence to temperature has been experimentally determined for several types of inorganic and biogenic carbonates (e.g., Dennis & Schrag, ; Henkes et al, ; Fernandez, Tang, & Rosenheim, ; Kele et al, ; Kluge & John, ;Bonifacie et al, ; Kelson, Huntington, Schauer, Saenger, & Lechler, ) and (Mangenot et al, ) can be applied to virtually any (Ca, Fe, Mg)CO 3 carbonate in the 0–350°C geologically‐relevant temperature range (Bonifacie et al, ). Over the last decade, the Δ 47 thermometry has been mostly applied for paleoclimatic reconstructions of fossil carbonates, with more recent application to reconstruct mild diagenetic conditions (ie., below 100°C) as for example by reconstructing paleotemperatures and fluid chemistries associated with cements and fractures (e.g., Bristow, Bonifacie, Derkowski, Eiler, & Grotzinger, ; Huntington, Budd, Wernicke, & Eiler, ; Budd, Frost, Huntington, & Allwardt, ; Loyd, Dickson, Scholle, & Tripati, ; Mangenot, Gasparrini, Gerdes, Bonifacie, & Rouchon, ; Mangenot, Gasparrini, Rouchon, & Bonifacie, ; Pagel et al, ), faults (Bergman, Huntington, & Crider, ; Fay‐Gomord et al, ; Swanson, Wernicke, Eiler, & Losh, ), and concretions (e.g., Loyd, Corsetti, Eiler, & Tripati, ; Dale, John, Mozley, Smalley, & Muggeridge, ) or identifying cryptic recrystallization of carbonate fossils (e.g., Bennett et al, ). However, when carbonates experience high temperatures, the initial abundance of 13 C 18 O 16 O 2 groups (and thus the Δ 47 value acquired at the time of precipitation) changes due to diffusional reordering of carbon and oxygen isotopes within the carbonate lattice.…”