Amanda Henck Schmidt

Oberlin College · Department of Geology

We examine the Holocene loess record in the Heye Catchment on the margins of the Tibetan Plateau (TP) and China Loess Plateau (CLP) to determine: the region to which the Heye Catchment climate is more similar; temporal change in wind strength; and modification of the loess record by mass wasting and human activity. Luminescence and radiocarbon dati...

Over the past century, lake degradation has increased around the world. Jiuzhaigou World Natural Heritage Site in southwestern China has been experiencing water nutrient enrichment, accelerated swamping, and algal biomass increases. These problems are likely associated with enhanced local anthropogenic activities over the past decades. In this stud...

We use 25 new measurements of in situ produced cosmogenic 26Al and 10Be in river sand, paired with estimates of dissolved load flux in river water, to characterize the processes and pace of landscape change in central Cuba. Long-term erosion rates inferred from 10Be concentrations in quartz extracted from central Cuban river sand range from 3.4–189...

Long-term erosion rates in Tasmania, at the southern end of Australia's Great Dividing Range, are poorly known; yet, this knowledge is critical for making informed land-use decisions and improving the ecological health of coastal ecosystems. Here, we present quantitative, geologically relevant estimates of erosion rates for the George River basin,...

Tropical islands, including many in island arcs, are subjected to recurring disturbances from extreme storms such as tropical cyclones. To test whether such storms influence cosmogenic nuclide concentrations such that they do not reflect long-term rates of erosion, we measured meteoric and in situ ¹⁰Be in river sediment samples from Dominica, an an...

We consider measurements of both in situ produced cosmogenic nuclides and dissolved load flux to characterize the processes and pace of landscape change in central Cuba. The tropical landscape of Cuba is losing mass in multiple ways, making it difficult to quantify total denudation rates and thus to assess the impact of agricultural practices on ra...

Accurately inferring erosion rates from cosmogenic isotope concentrations in river sand assumes temporally steady concentrations; few studies test this assumption. Following Hurricane María in Puerto Rico, we quantified temporal variability in meteoric and in situ ¹⁰Be (¹⁰Bem, ¹⁰Bei) on sand-sized grains of riverine transported material in landslid...

Water is essential for a sustainable economic prosperity, but rapid economic growth and intensive agricultural activities usually cause water pollution. The middle and lower reaches of China’s Yangtze River Basin were urbanized and industrialized much earlier than the upper reach and have been suffering from water pollution. In the past two decades...

Temporal water storage is a fundamental component of the terrestrial water cycle. Methods of estimating water storage variations are often limited to specific, well-monitored locations, and/or system scales. Thus, measures of storage from small systems can be difficult to compare to large systems. Here we compare three independent methods of estima...

Chinadialogue is a bilingual website, with news, features and reports on environmental issues in China and the rest of the world. Our presentations focuses on the role humans may have had on biodiversity in Jiuzhaigou National Nature Area (northern Sichuan) and some present national policies may reduce that biodiversity.

Since the 1990s, cosmogenic nuclides have revolutionized the study of Earth surface processes, particularly the understanding of rates and dates. These nuclides, including ³He, ¹⁰Be, ¹⁴C, ²¹Ne, ²⁶Al, and ³⁶Cl, enable dating of landforms and the measurement of erosion rates both at the scale of drainage basins and at specific locations on Earth's su...

Dissolved organic carbon (DOC) is a complex mixture of organic compounds that play critical roles in the environment such as ecosystem functioning, the carbon cycle and contaminant transfer. Advances in spectroscopic technology and methods now enable us to readily evaluate the optical properties and chemical composition of DOC, including fluorescen...

The lower Jinsha River has the highest sediment yield rates of the entire Yangtze watershed; these high yields have previously been attributed to a mix of the local geologic setting as well as intensive human land use, particularly agriculture. Prior studies have not quantified long-term background rates of sediment generation, making it difficult...

Land use changes, such as deforestation and agricultural expansion, increase soil erosion on the scale of hillslopes and small drainage basins. However, the effects of these changes on the sediment load in rivers is poorly quantified, with a few studies scattered globally, and only 10 data points in the world's most populous nation, China. At 20 di...

Using measurements of in situ and meteoric ¹⁰Be in fluvial sand to measure erosion rates, quantify soil loss, and trace sediment sources and sinks relies on the assumption that such sediment is well-mixed and representative of the upstream area. We test this assumption at 13 river junctions in three tributary watersheds (200–2500 km²) to the Mekong...

Cosmogenic isotopes, short‐lived radionuclides, elemental concentrations and thermochronometric indicators are measured in river sand to quantify erosion rates and trace sediment sources, and/or infer erosional processes. Interpretations of detrital sediment analyses are often based on the rarely tested assumption of time‐invariant tracer concentra...

Toward the goals of returning the landscape of Jiuzhaigou National Nature Reserve to a perceived “natural” state and protecting the environment, the Reserve in 1998–2002 implemented forest preservation policies that included restrictions on forestry, agriculture, and animal herding practiced by resident Tibetans. To document the effects of these la...

Present-day landscapes are shaped by historical forces that combine natural change (generated by climate, geological processes etc.) with anthropogenic change (locally generated in interaction with larger political and economic forces). In the Jiuzhaigou region of Northern Sichuan, humans have shaped landscapes to their needs for at least 3500 year...

In order to understand better if and where erosion rates calculated using in situ 10Be are affected by contemporary changes in land use and attendant deep regolith erosion, we calculated erosion rates using measurements of in situ 10Be in quartz from 52 samples of river sediment collected from three tributaries of the Mekong River (median basin are...

Grain-size dependencies in fallout radionuclide activity have been attributed to either increase in specific surface area in finer grain sizes or differing mineralogical abundances in different grain sizes. Here, we consider a third possibility, that the concentration and composition of grain coatings, where fallout radionuclides reside, controls t...

In order to understand better if and where long-term erosion rates calculated using in situ 10Be are affected by contemporary changes in land use and attendant deep regolith erosion, we calculated erosion rates using measurements of in situ 10Be in quartz from 52 samples of river sediment collected from three tributaries of the Mekong River (median...

Unsupported Pb-210 is a commonly used as both a tracer and geochronometer for fluvial, lacustrine, and pedogenic studies. Complications arise when Pb-210 is measured in detrital, fluvial sediments. Because Pb-210 resides both in the substrate (supported) and in grain coatings (excess or unsupported), measuring Pb-210 requires subtracting a proxy fo...

Significance Adapting agricultural systems to the high-altitude environment of the Tibetan Plateau has long been considered a major challenge for farmers. It has been asserted previously that the ecological characteristics of wheat and barley delayed their spread into East Asia. We argue instead that the ability of these crops to tolerate frost and...

Jiuzhaigou National Park (JNP) is a site of global conservation significance. Conservation policies in JNP include the implementation of two national reforestation programs to increase forest cover and the exclusion of local land-use. We use archaeological excavation, ethnographic interviews, remote sensing and vegetation surveys to examine the imp...

China’s tuigeng huanlin or “Returning Farmland to Forest” (RFFP) program has been widely praised as the world’s largest and most successful payment for ecosystem services program, as well as a major contributor to China’s dramatic increase in forest cover from perhaps as low as 8% in 1960 to about 21% today. By compensating rural households for the...

This paper examines human impact on stands and individual trees of Pinus yunnanensis growing near the small mountain villages of Pianshui and Yangjuan in southwestern Sichuan Province, China. In an effort to assess whether use of these forests was sustainable, we examined the effects of human use in two ways. First, we directly measured the effect...

China's tuigeng huanlin or “Returning Farmland to Forest” (RFFP) program has been widely praised as the world's largest and most successful payment for ecosystem services program, as well as a major contributor to China's dramatic increase in forest cover from perhaps as low as 8% in 1960 to about 21% today. By compensating rural households for the...

As one of the largest economical hubs in southwestern China, Chengdu is witnessing fast urbanization characterized by rapid urban sprawl, population growth, infrastructural construction, and motorization. However, this rapid urbanization may lead to environmental degradation, placing human health at risk. In this study, toxic metals in road dust an...

Environmental challenges are often global in scope and require solutions that integrate knowledge across disciplines, cultures, and organizations. Solutions to these challenges will come from diverse teams and not from individuals or single academic disciplines; therefore, graduate students must be trained to work in these diverse teams. In this ar...

Chinese Communist Party doctrine promotes the Confucian belief that the environment should be subjugated to man's will, and modern policies have been identified as compounding environmental degradation caused by historical agricultural practices. In this context, social scientists report massive increases in erosion throughout China, an assertion v...

Global data suggest that erosion rates variously scale with steepness or climate forcing (precipitation or glacial excavation), but the relative influence of these factors has proven difficult to assess without comparisons from a single location. A new suite of detrital 10 Be data from the Three Rivers Region, SE Tibet is used to examine the relati...

Analysis of suspended sediment transport data for rivers in Yunnan and Tibet shows that monsoon flows control effective discharge. We calculate effective discharge, defined as the discharge that transports the most sediment, for 44 stations for which there is at least one complete year of daily suspended sediment concentration and mean daily discha...

Small, irregular terraces on hillslopes, or terracettes, are common landscape features throughout west central China. Despite their prevalence, there is limited understanding of the nature of these topographic features, the processes that form them, and the role humans played in their formation. We used an interdisciplinary approach to investigate...

Farmers of the Nuosu Yi ethnic group in the Upper Baiwu watershed report reductions in the availability of local forest resources. A team of interdisciplinary scientists worked in partnership with this community to assess the type and extent of social-ecological change in the watershed and to identify key drivers of those changes. Here, we combine...

Farmers of the Nuosu Yi ethnic group in the Upper Baiwu watershed report reductions in the availability of local forest resources. A team of interdisciplinary scientists worked in partnership with this community to assess the type and extent of social-ecological change in the watershed and to identify key drivers of those changes. Here, we combine...

The administration of Jiuzhaigou National Park in Sichuan Province, China, is in the process of considering a range of upgrades to their sanitation and wastewater treatment systems. Their case history involves an ongoing series of engineering design flaws and management failures. The administration of the Park identified sustainability, environment...

Ever since the disastrous floods of 1998, the Chinese government has used the Natural Forest Protection and Sloping Land Conversion Programs to promote afforestation and reforestation as means to reduce runoff, control erosion, and stabilize local livelihoods. These two ambitious programs have been reported as large-scale successes, contributing to...

The three-dimensional velocity field in southeastern Tibet is notable for its expression in the local topographic field. To investigate the links between strain and topography we examine the topography of the eastern Himalayan Syntaxis centered on the Namche Barwa region, considering wavelengths down to 25km. We are testing a hypothesis linking kin...