\documentclass[10pt]{article}

\usepackage{fullpage}
\usepackage{setspace}
\usepackage{parskip}
\usepackage{titlesec}
\usepackage[section]{placeins}
\usepackage{xcolor}
\usepackage{breakcites}
\usepackage{lineno}
\usepackage{hyphenat}





\PassOptionsToPackage{hyphens}{url}
\usepackage[colorlinks = true,
            linkcolor = blue,
            urlcolor  = blue,
            citecolor = blue,
            anchorcolor = blue]{hyperref}
\usepackage{etoolbox}
\makeatletter
\patchcmd\@combinedblfloats{\box\@outputbox}{\unvbox\@outputbox}{}{%
  \errmessage{\noexpand\@combinedblfloats could not be patched}%
}%
\makeatother


\usepackage{natbib}




\renewenvironment{abstract}
  {{\bfseries\noindent{\abstractname}\par\nobreak}\footnotesize}
  {\bigskip}

\titlespacing{\section}{0pt}{*3}{*1}
\titlespacing{\subsection}{0pt}{*2}{*0.5}
\titlespacing{\subsubsection}{0pt}{*1.5}{0pt}


\usepackage{authblk}


\usepackage{graphicx}
\usepackage[space]{grffile}
\usepackage{latexsym}
\usepackage{textcomp}
\usepackage{longtable}
\usepackage{tabulary}
\usepackage{booktabs,array,multirow}
\usepackage{amsfonts,amsmath,amssymb}
\providecommand\citet{\cite}
\providecommand\citep{\cite}
\providecommand\citealt{\cite}
% You can conditionalize code for latexml or normal latex using this.
\newif\iflatexml\latexmlfalse
\providecommand{\tightlist}{\setlength{\itemsep}{0pt}\setlength{\parskip}{0pt}}%

\AtBeginDocument{\DeclareGraphicsExtensions{.pdf,.PDF,.eps,.EPS,.png,.PNG,.tif,.TIF,.jpg,.JPG,.jpeg,.JPEG}}

\usepackage[utf8]{inputenc}
\usepackage[english]{babel}



\usepackage{float}








\begin{document}

\title{Strong Physical Contrasts across Two Mid-lithosphere Discontinuities
beneath the Northwestern United States: Evidence for Cratonic Mantle
Metasomatism}



\author[1]{Tianze Liu}%
\author[2]{Emily Joyce Chin}%
\author[3]{Peter M. Shearer}%
\affil[1]{University of California, San Diego}%
\affil[2]{Scripps Institution of Oceanography}%
\affil[3]{U.C. San Diego}%


\vspace{-1em}



  
  \date{May 22, 2024}


\begingroup
\let\center\flushleft
\let\endcenter\endflushleft
\maketitle
\endgroup





\selectlanguage{english}
\begin{abstract}
Mid-lithosphere discontinuities are seismic interfaces likely located
within the lithospheric mantle of stable cratons, which typically
represent velocities decreasing with depth. The origins of these
interfaces are poorly understood due to the difficulties in both
characterizing them seismically and reconciling the observations with
thermal-chemical models of cratons. Metasomatism of the cratonic
lithosphere has been reported by numerous geochemical and petrological
studies worldwide, yet its seismic signature remains elusive. Here, we
identify two distinct mid-lithosphere discontinuities at
\textasciitilde{}89 and \textasciitilde{}115 km depth beneath the
eastern Wyoming craton and the southwestern Superior craton by analyzing
seismic data recorded by two longstanding stations. Our waveform
modeling shows that the shallow and deep interfaces represent isotropic
velocity drops of 2--9\% and 3--10\%, respectively, depending on the
contributions from changes in radial anisotropy and density. By building
a thermal-chemical model including the regional xenolith thermobarometry
constraints and the experimental phase-equilibrium data of mantle
metasomatism, we show that the shallow interface probably represents the
metasomatic front, below which hydrous minerals such as amphibole and
phlogopite are present, whereas the deep interface may be caused by the
onset of carbonated partial melting. The hydrous minerals and melts are
products of mantle metasomatism, with CO2-H2O-rich siliceous melt as a
probable metasomatic reagent. Our results suggest that mantle
metasomatism is probably an important cause of mid-lithosphere
discontinuities worldwide, especially near craton boundaries, where the
mantle lithosphere may be intensely metasomatized by fluids and melts
released by subducting slabs.%
\end{abstract}%



\sloppy




\selectlanguage{english}
\FloatBarrier
\end{document}

