<?xml version="1.0" encoding="utf-8"?><mads xmlns="http://www.loc.gov/mads/" xmlns:mods="http://www.loc.gov/mods/v3" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.loc.gov/mads/
mads.xsd"><authority><topic authority="http://AATesaurus.cultura.gencat.cat/aat/getty_en">geochemistry</topic></authority><related type="broader"><topic>chemistry</topic></related><related type="broader"><topic>earth sciences</topic></related><variant type="other"><topic>geochemical</topic></variant> <note xml:lang="en"><![CDATA[ Study of the chemical composition of the earth. It involves estimating the abundance of the constituent elements and their isotopes, as well as their distribution in the lithosphere, atmosphere, biosphere, and hydrosphere, and in the rocks and minerals that make up the earth. ]]></note></mads>