It is common for subsurface flow to transition between porous and fractured media. Two examples include vertical infiltration of precipitation through a permeable soil overlying a fractured bedrock, and horizontal ground water flow through a combination of porous and fractured geologic units. A reduction in flow or flow impedance may occur across these interfaces caused by head losses associate...

Field surveys of channel width w and drainage area A in bedrock channel reaches reveal relationships where w 5 cA, similar to the classic hydraulic geometry of alluvial channels. Data from five mountain channel networks support the assumption used in many landscape evolution models that an alluvial hydraulic geometry relationship where b 5 0.3–0.5 holds for bedrock channel systems. Although the...

The lowermost Mississippi River, defined herein as the river segment downstream of the Old River Control Structure and hydrodynamically influenced by the Gulf of Mexico, extends for approximately 500 km. This segment includes a bedrock (or more precisely, mixed bedrock-alluvial) reach that is bounded by an upstream alluvial-bedrock transition and a downstream bedrock-alluvial transition. Here w...

The alkaline playas near Atlin, British Columbia, Canada are likely one of the few surface environments on Earth where contemporaneous formation hydromagnesite and magnesite occurs at temperatures that do not exceed 15 °C. This environment offers a unique opportunity to examine impact different mechanisms Mg isotope compositions Mg-carbonate minerals low temperature. In this study, we report co...

Hyperaccumulation is an unusual plant response to metaliferous soils. Such soils like those derived from ultramafic rocks, have elevated concentrations of heavy metals, mainly Ni, Cr, Zn and Cd. Most plants growing on these soils exclude metals from their shoots as excessive accumulation of heavy metals is toxic to the majority of plants. However, about 2% of plants growing on metaliferous soil...

mafic and ultramafic plutonic igneous bodies, with small and big outcrops, between shemshak rock units (jurassic) are observed in east of imam zadeh hashem, in southern guilan province. ultramafic cumulates consist of clinopyroxenite, and plagiofer clinopyroxenite, olivine clinopyroxenite, and mafic rocks, based on mineralogy consist of gabbros, olivine gabbros, biotite gabbros and amphibole ga...

Earth's land surface teems with life. Although the distribution of ecosystems is largely explained by temperature and precipitation, vegetation can vary markedly with little variation in climate. Here we explore the role of bedrock in governing the distribution of forest cover across the Sierra Nevada Batholith, California. Our sites span a narrow range of elevations and thus a narrow range in ...

We compared the elemental composition of soil and bedrock samples to determine the extent of chemical weathering and the nature of the soil parent material in alpine soils on Vermont's highest summit. Previously it was unclear whether these soils formed through weathering of bedrock, glacial till, or eolian sediment, or solely through the accumulation of organic matter. In eighteen profiles, no...