Sensitivity of Soil Chemical Erosion Rate to Climate and Dust Along a 2.8‐km Elevation Transect at San Jacinto Mountain, California

Chemical weathering is of wide interest because it breaks down minerals, releases nutrients, weakens rock, and draws down atmospheric CO 2 . To quantify the sensitivity of soil chemical erosion rate to climate and dust, we measured soil chemical erosion rate, dust deposition rate, and soil climate at 18 ridgetop sites along a ∼2.8‐km elevation transect at San Jacinto Mountain, California, which spans a wide range in climate (∼18°C in mean annual temperature and ∼600 mm in mean annual precipitation) within compositionally similar granitic bedrock. Our measurements imply a moderate sensitivity of chemical erosion rate to temperature, with an apparent Arrhenius activation energy of 36 ± 28 kJ mol −1 . The most striking relationships in these data are a positive correlation of chemical depletion fraction (CDF) with mean annual soil temperature and a positive correlation of chemical erosion rate with mineral supply rate. These relationships, paired with the absence of significant relationships of CDF or chemical erosion rate with mean annual soil volumetric water content, imply a stronger sensitivity of soil chemical erosion to temperature and mineral supply than to volumetric water content across the study sites. Dust is chemically distinct from the local parent rock, and dust deposition rates represent 2%–31% of the mineral supply rates from the parent rock. Thus, dust is a secondary but nonnegligible contributor to soil composition and mass, highlighting the importance of accounting for dust in investigations of soil chemical weathering. Together, these observations motivate further investigation into connections between dust, climate, and chemical erosion in mountain ecosystems.