Gen Li

University of California, Santa Barbara | UCSB · Department of Earth Science

Here we assess earthquake volume balance and the growth of mountains in the context of a new landslide inventory for the Mw7.9 Wenchuan earthquake in central China. Coseismic landslides were mapped from high-resolution remote imagery using an automated algorithm and manual delineation, which allows us to distinguish clustered landslides that can bi...

Large earthquakes can construct mountainous topography by inducing rock uplift but also erode mountains by causing landslides. Observations following the 2008 Wenchuan earthquake show that landslide volumes in some cases match seismically induced uplift, raising questions about how the actions of individual earthquakes accumulate to build topograph...

Permafrost influences 25% of land in the Northern Hemisphere, where it stabilizes the ground beneath communities and infrastructure and sequesters carbon. However, the coevolution of permafrost, river dynamics, and vegetation in Arctic environments remains poorly understood. As rivers meander, they erode the floodplain at cutbanks and build new lan...

Plain Language Summary Rivers transport sediment and organic carbon (OC) from the mountains to the sea, and river movement affects sediment and OC transit times in landscapes. Understanding the controls on timescales of river movement is critical for assessing how fluvial processes influence the terrestrial carbon cycle. While previous work has qua...

Soil organic matter (SOM) is a critical player in the global carbon cycle and a common paleoclimate archive, yet the mechanisms governing its evolution, particularly in subsoil (>30 cm) systems, remain less well understood. To better characterize subsoil SOM dynamics, we investigated the isotopic compositions of SOM in fine (<2 μm) and coarser (>2...

Plain Language Summary Unraveling the provenance of aeolian dust deposited in the oceans is critical for understanding marine biogeochemical cycles, past climate changes, and dust transport mechanisms. Here we measured the (²³⁴U/²³⁸U) activity ratio of marine sediments in the North Pacific Ocean to understand the source and pre‐deposition time of d...

In active mountains, landslides are the primary agent of erosion that readily generates materials with high weatherability. Understanding the linkage between landslide activity, erosion, and chemical weathering is critical for assessing how tectonic uplift affects the carbon cycle and Earth's climate. However, quantifying the contribution to chemic...

Permafrost degradation is altering biogeochemical processes throughout the Arctic. Thaw‐induced changes in organic matter transformations and mineral weathering reactions are impacting fluxes of inorganic carbon (IC) and alkalinity (ALK) in Arctic rivers. However, the net impact of these changing fluxes on the concentration of carbon dioxide in the...

Riverine solute chemistry has long been used to infer modern weathering fluxes and processes by assuming that river‐dissolved loads are conservative mixtures of weathering products of different lithologies. Secondary carbonate precipitation and re‐dissolution are important processes that can alter the original weathering fluxes. However, it remains...

CO2 mineral carbonation induced by microalgae is an emerging approach to carbon capture, utilization, and storage (CCUS). Freshwater cyanobacteria are common microalgae in nature that can raise the pH of eutrophic waters and drive the precipitation of carbonate. Still, limited studies have been conducted to evaluate and select appropriate cyanobact...

The paleosol-based proxies derived from the ancient aeolian deposits on the Chinese Loess Plateau (CLP) are commonly used to infer past changes in climate and environment, but those proxies often display distinct spatiotemporal trends. Several mechanisms have been proposed to explain the differences between the proxy records from the CLP. However,...

Plain Language Summary The provenance of silt‐sized particles in the Taklimakan Desert is critical for understanding aridification and climate dynamics in central Asia, as well as the production mechanism of dust—a key player in the global biogeochemical cycles of nutrient elements. Here, we measured the uranium‐strontium‐neodymium isotopes in silt...

Arctic river systems erode permafrost in their banks and mobilize particulate organic carbon (OC). Meandering rivers can entrain particulate OC from permafrost many meters below the depth of annual thaw, potentially enabling the production of greenhouse gases. However, the amount and fate of permafrost OC that is mobilized by river erosion is uncer...

Plain Language Summary High relief and steep slopes are characteristic of mountainous landscapes. Hillslopes become unstable once their gradients exceed a critical angle set by hillslope material strength. Rock masses residing on hillslopes steeper than the critical angle are prone to landslide failures, representing a major hazard and primary agen...

Understanding weathering processes in landslide-dominated catchments is critical for evaluating the role of landslides in chemical weathering and the global carbon cycle. Previous studies have focused on solute concentrations in landslide-impacted landscapes, but have paid less attention to developing isotopic tracers of landslide-induced weatherin...

Plain Language Summary Soil organic matter inherits the carbon isotope signal (¹³C/¹²C) of the aboveground biomass and is widely used to infer past changes in vegetation biomes. However, the isotope fractionation during soil organic matter decomposition remains loosely constrained, biasing its interpretation. Based on the Holocene ancient soil (pal...

Earthquakes play a fundamental role in the evolution of Earth’s topography through co-seismic uplift and subsidence, as well as erosion through widespread landslides induced by ground motion. Earthquake-induced landslides can result in exceptional increases in the transfer of mass from landscapes, supplying sediment to rivers where impacts can last...

Arctic river systems erode permafrost in their banks and mobilize particulate organic carbon (OC). Meandering rivers can entrain particulate OC from permafrost many meters below the depth of annual thaw, potentially enabling OC oxidation and the production of greenhouse gases. However, the amount and fate of permafrost OC that is mobilized by river...

Permafrost soils store approximately twice the amount of carbon currently present in Earth’s atmosphere and are acutely impacted by climate change due to the polar amplification of increasing global temperature. Many organic-rich permafrost sediments are located on large river floodplains, where river channel migration periodically erodes and re-de...

In mountain ranges, earthquakes can trigger widespread landsliding and mobilize large amounts of organic carbon by eroding soil and vegetation from hillslopes. Following a major earthquake, the landslide-mobilized organic carbon can be exported from river catchments by physical sediment transport processes or stored within the landscape where it ma...

This study investigated the reaction processes of microbially induced magnesium carbonate precipitation (MIMP) with Sporosarcina pasteurii (ATCC 11859) and evaluated its feasibility for controlling desertification in the desert areas in Northwest China. We explored systematically bacterial growth curves, mineralogy of precipitates, and relative che...

Significance Coal combustion releases CO 2 but also leaves behind solid waste, or fly ash, which contains considerable amounts of carbon. The organic carbon sourced from fly ash resists chemical breakdown, and we find that it now contributes nearly half of the fossil organic carbon exported by the Chang Jiang—the largest river in Asia. The fly ash...

Landslides are a major natural hazard and act as a primary driver of erosion, chemical weathering and organic carbon transfer in mountain ranges. Evaluating the impact of landslides on Earth systems requires knowledge about the controls on their size, which are not well understood. Here we show that topographic stress, resulting from the interactio...

In mountain ranges, earthquakes can trigger widespread landsliding and mobilise large amounts of organic carbon by eroding soil and vegetation from hillslopes. Following a major earthquake, the landslide-mobilised organic carbon can be exported from river catchments by physical sediment transport processes, or stored within the landscape where it m...

Finely disseminated calcites and MS-S(z) model The paleosol-CO2 proxy suffers from the largely unconstrained S(z) (soil-respired CO2 concentration at depth z during the formation time of pedogenic carbonate). Here, based on both modern soil observations and paleosol analyses from the Chinese Loess Plateau (CLP), we propose two refinements to this m...

Pedogenic carbonate is an invaluable archive for reconstructing continental paleoclimate and paleoecology. The δ13C of pedogenic carbonate (δ13Cc) has been widely used to document the rise and expansion of C4 plants over the Cenozoic. This application requires a fundamental presumption that in soil pores, soil-respired CO2 dominates over atmospheri...

Quantifying ancient atmospheric pCO 2 provides valuable insights into the interplay between greenhouse gases and global climate. Beyond the 800-ky history uncovered by ice cores, discrepancies in both the trend and magnitude of pCO 2 changes remain among different proxy-derived results. The traditional paleosol pCO 2 paleobarometer suffers from lar...

Large earthquakes initiate chains of surface processes that last much longer than the brief moments of strong shaking. Most moderate‐ and large‐magnitude earthquakes trigger landslides, ranging from small failures in the soil cover to massive, devastating rock avalanches. Some landslides dam rivers and impound lakes, which can collapse days to cent...

Infrequent extreme events such as large earthquakes pose hazards and have lasting impacts on landscapes and biogeochemical cycles. Sediments provide valuable records of past events, but unambiguously identifying event deposits is challenging because of nonlinear sediment transport processes and poor age control. Here, we have been able to directly...

Landslides constitute a hazard to life and infrastructure and their risk is mitigated primarily by reducing exposure. This requires information on landslide hazard on a scale that can enable informed decisions. Such information is often unavailable to, or not easily interpreted by, those who might need it most (e.g. householders, local governments...

To evaluate the roles of climate and hydrology in continental-scale silicate weathering, we applied Li isotopes to the Yellow River and systematically investigated seasonal Li flux, Li isotopic compositions and potential sources. We collected samples from the middle reaches of the Yellow River weekly over the full hydrological year of 2013. We find...

Erosion of organic carbon from the terrestrial biosphere and sedimentary rocks plays an important role in the global carbon cycle across a range of timescales. Over geological timescales (>10 ⁴ years), erosion and burial of particulate organic carbon (POC) from the terrestrial biosphere (POC biosphere ) is an important CO 2 sink, while oxidation of...

Landslides constitute a hazard to life and infrastructure, and their risk is mitigated primarily by reducing exposure. This requires information on landslide hazard at a scale that can enable informed decisions about how to respond to that hazard. Such information is often unavailable to, or not easily interpreted by, those who might need it most (...

Drainage divide migration reorganizes river basins, redistributing erosive energy and contributing to feedbacks between tectonics, erosion, and climate. However, the conditions governing divide migration and the time scales on which it occurs are poorly understood. By connecting channels to hillslopes in steep landscapes, landslides are expected to...

CO2 absorption and carbonate precipitation are the two core processes controlling the reaction rate and path of CO2 mineral sequestration. Whereas previous studies have focused on testing reactive crystallization and precipitation kinetics, much less attention has been paid to absorption, the key process determining the removal efficiency of CO2. I...

Thousands of landslides occurred during the April 2015 Gorkha earthquake in Nepal. Previous work using satellite imagery mapped nearly 25,000 coseismic landslides. In this study, the satellite-based mapping was analyzed in three areas where field deployment was also conducted—the Budhi Gandaki, Trishuli, and Indrawati river valleys—to better charac...

Earthquakes cause widespread landslides that can increase erosional fluxes observed over years to decades. However, the impact of earthquakes on denudation over the longer timescales relevant to orogenic evolution remains elusive. Here we assess erosion associated with earthquake-triggered landslides in the Longmen Shan range at the eastern margin...

Coseismic landslides pose immediate and prolonged hazards to mountainous communities, and provide a rare opportunity to study the effect of large earthquakes on erosion and sediment budgets. By mapping landslides using high-resolution satellite imagery, we find that the 25 April 2015 Mw7.8 Gorkha earthquake and aftershock sequence produced at least...

The homeostatic balance of Earth's long-term carbon cycle and the equable state of Earth's climate are maintained by negative feedbacks between the levels of atmospheric CO2 and the chemical weathering rate of silicate rocks. Though clearly demonstrated by well-controlled laboratory dissolution experiments, the temperature dependence of silicate we...

On geological time scales, the erosion of carbon from the terrestrial biosphere and its burial in sediments can counter CO2 emissions from the solid Earth. Earthquakes may increase the erosion of this biospheric carbon and supply it to mountain rivers by triggering landslides, which rapidly strip hillslopes of vegetation and soil. Over the long ter...

Evaluating the influence of earthquakes on erosion, landscape evolution, and sediment-related hazards requires understanding fluvial transport of material liberated in earthquake-triggered landslides. The location of landslides relative to river channels is expected to play an important role in post-earthquake sediment dynamics. In this study, we a...

Large earthquakes alter physical and chemical processes at the Earth’s surface, triggering landslides, fracturing rock, changing large-scale permeability, and influencing hydrologic pathways. The resulting effects on global chemical cycles are not fully known. Here we show changes in the dissolved chemistry of the Min Jiang, in the Yangtze River he...

Large earthquakes in active mountain belts can trigger landslides, which mobilize large volumes of clastic sediment. Delivery of this material to river channels may result in aggradation and flooding, while sediment residing on hillslopes may increase the likelihood of subsequent landslides and debris flows. Despite recognition of these processes,...

Worldwide dam building in large river basins has substantially altered the carbon cycle by trapping much of the riverine transported particulate organic carbon (POC) in terrestrial reservoirs. Here we take the Changjiang (Yangtze) River basin, in which ~50,000 dams were built over the past 50 years, as an example to evaluate the effect of dam build...