Boron isotope composition of detrital tourmaline: A new tool in provenance analysis

Lithos ◽  
2021 ◽  
pp. 106360
Author(s):  
Ronghua Guo ◽  
Xiumian Hu ◽  
Eduardo Garzanti ◽  
Wen Lai
Keyword(s):  
Isotope Composition ◽  
Boron Isotope ◽  
Provenance Analysis

scholarly journals A record of Neogene seawater <i>δ</i><sup>11</sup>B reconstructed from paired <i>δ</i><sup>11</sup>B analyses on benthic and planktic foraminifera

2017 ◽  
Vol 13 (2) ◽  
pp. 149-170 ◽  
Author(s):  
Rosanna Greenop ◽  
Mathis P. Hain ◽  
Sindia M. Sosdian ◽  
Kevin I. C. Oliver ◽  
Philip Goodwin ◽  
...  
Keyword(s):  
Carbon Cycle ◽  
Middle Miocene ◽  
Isotope Composition ◽  
Boron Isotope ◽  
Mineral Formation ◽  
Secondary Mineral ◽  
Cycle Model ◽  
Planktic Foraminifera ◽  
Carbon Cycle Model ◽  
Secondary Mineral Formation

Abstract. The boron isotope composition (δ11B) of foraminiferal calcite reflects the pH and the boron isotope composition of the seawater the foraminifer grew in. For pH reconstructions, the δ11B of seawater must therefore be known, but information on this parameter is limited. Here we reconstruct Neogene seawater δ11B based on the δ11B difference between paired measurements of planktic and benthic foraminifera and an estimate of the coeval water column pH gradient from their δ13C values. Carbon cycle model simulations underscore that the ΔpH–Δδ13C relationship is relatively insensitive to ocean and carbon cycle changes, validating our approach. Our reconstructions suggest that δ11Bsw was  ∼  37.5 ‰ during the early and middle Miocene (roughly 23–12 Ma) and rapidly increased during the late Miocene (between 12 and 5 Ma) towards the modern value of 39.61 ‰. Strikingly, this pattern is similar to the evolution of the seawater isotope composition of Mg, Li and Ca, suggesting a common forcing mechanism. Based on the observed direction of change, we hypothesize that an increase in secondary mineral formation during continental weathering affected the isotope composition of riverine input to the ocean since 14 Ma.

No ion is an island: Multiple ions involved during boron incorporation into CaCO3

2021 ◽  
Author(s):  
Michael Henehan ◽  
Christa Klein-Gebbinck ◽  
Gavin Foster ◽  
Jill Wyman ◽  
Mathis Hain ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Isotope Fractionation ◽  
Isotope Composition ◽  
Boron Isotope ◽  
Minor Role ◽  
Growth Mechanisms ◽  
Minor Elements ◽  
Vital Effects ◽  
Biogenic Carbonates ◽  
Trace And Minor Elements

&lt;p&gt;Boron isotope ratios, as measured in marine calcium carbonate, are a proven tracer of past seawater and calcifying fluid pH and thus a powerful tool for the reconstruction of past atmospheric CO&lt;sub&gt;2&lt;/sub&gt; and monitoring of coral physiology. For such applications, understanding the inorganic baseline upon which foraminiferal vital effects or coral pH upregulation are superimposed should be an important prerequisite. Yet, investigations into boron isotope fractionation in synthetic CaCO&lt;sub&gt;3&amp;#160;&lt;/sub&gt;polymorphs have often reported variable and even conflicting results, implying that we may not fully understand pathways of boron incorporation into calcium carbonate. &amp;#160;Here we address this topic with experimental data from calcite and aragonite precipitated across a range of pH in the presence of both Mg and Ca. We confirm the results of previous studies that the boron isotope composition of inorganic aragonite precipitates closely reflects that of aqueous borate ion, but that calcites display a higher degree of scatter, and diverge from the boron isotope composition of borate ion at low pH. We discuss these findings with reference to the simultaneous incorporation of other trace and minor elements, and highlight a number of mechanisms by which crystal growth mechanisms may influence the concentration and isotope composition of boron in CaCO&lt;sub&gt;3&lt;/sub&gt;. In particular, we highlight the potential importance of surface electrostatics in driving variability in published synthetic carbonate datasets. Importantly for palaeo-reconstruction, however, these electrostatic effects are likely to play a much more minor role during natural precipitation of biogenic carbonates.&lt;/p&gt;

scholarly journals Reconstructing the secular evolution of boron isotope composition of seawater from evaporites

2021 ◽  
Author(s):  
James Rae ◽  
Hana Jurikova ◽  
Fernando Gázquez ◽  
Eszter Sendula ◽  
Robert Bodnar ◽  
...  
Keyword(s):  
Isotope Composition ◽  
Boron Isotope ◽  
Secular Evolution

Boron isotope composition of coals: a potential tracer of organic contaminated fluids

2004 ◽  
Vol 19 (10) ◽  
pp. 1625-1636 ◽  
Author(s):  
Lynda B Williams ◽  
Richard L Hervig
Keyword(s):  
Isotope Composition ◽  
Boron Isotope
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