A tenfold slowdown in river meander migration driven by plant life

Ielpi, Alessandro; Lapôtre, M. G. A.

doi:10.1038/s41561-019-0491-7

Cited by 101 publications

(106 citation statements)

References 35 publications

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“…Here we utilize the stratigraphy of the Jezero delta (Goudge et al, 2018) and combine it with a new empirical relationship between the lateral migration rate of single-thread rivers and channel width 10.1029/2019AV000141 (Ielpi & Lapôtre, 2020) to infer the duration of surface-runoff events that deposited the sediments. We combine the empirical relationship of Ielpi and Lapôtre (2020), corrected for climate and scaled to Mars gravity, with orbiter-based measurements of river-deposit stratigraphy to estimate sediment aggradation rates and determine the minimum duration of delta formation (i.e., the time it would have taken to form the Jezero delta in a single, continuous sediment-transport event). We then independently estimate the total timespan over which the Jezero delta formed, including dry spells, using the technique of Buhler et al (2014).…”

Section: Research Articlementioning

confidence: 99%

“…However, the discharge record of one such stream-the Amargosa River draining into Death Valley, California-is available through one gauging station that recorded near-continuous data since 1962 at Tecopa, California. In the absence of a more inclusive and geographically varied database, the discharge record of the Amargosa River is herein considered as overall representative of other arid rivers in the unvegetated-river compilation of Ielpi and Lapôtre (2020). Bankfull discharge for the Tecopa gauging site was estimated from field observations as described in Ielpi and Lapôtre (2020).…”

Section: 1029/2019av000141mentioning

confidence: 99%

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The Pace of Fluvial Meanders on Mars and Implications for the Western Delta Deposits of Jezero Crater

Lapôtre

Ielpi

2020

AGU Advances

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Although there is little doubt that rivers once flowed on Mars' surface, how sustained and frequent their flows were remains enigmatic. Understanding the hydrology of early Mars, nonetheless, is a prerequisite to resolving the planet's climate history and the astrobiological potential of various ancient putative ecosystems. In 2021, NASA's Perseverance rover will attempt to land near ancient fluviodeltaic deposits in Jezero crater. Deltas offer enhanced organic-matter burial and preservation on Earth but translating this notion to early Martian environments remains speculative in the absence of information on flow intermittency and sedimentation rates. Here we develop a new model to infer the lateral migration rate of Martian river meanders, which, combined with orbiter-based observations of the fluviodeltaic deposits at Jezero crater, allows us to determine a minimum timescale for the formation of its delta. We then independently constrain the total duration of delta formation, including dry spells. Our best estimates suggest that delta formation spanned~19-37 years over a total duration of~380,000 years, i.e., that rivers flowed for a minimum~1 sol/15-30 Martian years and conceivably more frequently, but uncertainties on total duration are large. Despite a possibly arid climate, predicted sedimentation rates are high, suggesting a rapid burial of putative organics in distal deposits. Altogether, our results support Jezero crater's potential as a prime target to look for ancient Martian life and acquire samples to return to Earth. Any discrepancies between our predictions of the deposits' grain-to-bedform-scale architecture and future rover observations will shed critical light onto Mars' early surface environments. Plain Language Summary Rivers once flowed on Mars, but how often, and for how long? Answering these questions will increase our understanding of Mars' habitability at a time when life was already evolving on Earth. NASA's Perseverance rover will land by the remnants of an ancient river delta in Jezero crater. Here we develop a new model to calculate the pace of shifting Martian rivers, which, when applied to orbital observations of the Jezero delta, allows us to determine a minimum duration for delta formation. Combined with an independent estimate for the total duration of delta formation (including dry spells), our results suggest that the delta took a few decades to form over a total timespan of, most likely, hundreds of thousands of years. This result suggests that Mars was likely arid at the time, with rivers flowing for at least 1 Martian day every 15-30 Martian years, and possibly more often. Nonetheless, we predict that sediments would have been buried quickly in the delta, favoring the long-term preservation of possible organic matter. Altogether, our results confirm that Jezero crater is a prime location to understand Mars' early climate, look for traces of ancient Martian life, and return samples from for further analysis on Earth.

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Section: Research Articlementioning

confidence: 99%

Section: 1029/2019av000141mentioning

confidence: 99%

The Pace of Fluvial Meanders on Mars and Implications for the Western Delta Deposits of Jezero Crater

Lapôtre

Ielpi

2020

AGU Advances

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“…Because most geomorphic work takes place at bankfull or higher discharge (Wolman and Miller, ; Blom et al ., ; Francalanci et al ., ; Naito and Parker, ), desert rivers might be expected to experience limited migration compared to perennial rivers of wetter climate zones. Yet, ephemeral rivers flowing through some of the driest sites on Earth display morphodynamic complexities equal to humid‐climate rivers (Donselaar et al ., ; Li et al ., , ; Ielpi et al ., ) and, owing to the lack of bank vegetation, migrate significantly faster than their vegetated counterparts (Ielpi and Lapôtre, ). This realization prompts two questions: (i) How often do desert rivers migrate?…”

Section: Rationale and Study Areamentioning

confidence: 99%

Channel mobility drives a diverse stratigraphic architecture in the dryland Mojave River (California, USA)

Ielpi

Lapôtre

Finotello

et al. 2020

Earth Surf Processes Landf

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The links between flood frequency and rates of channel migration are poorly defined in the ephemeral rivers typical of arid regions. Exploring these links in desert fluvial landscapes would augment our understanding of watershed biogeochemistry and river morphogenesis on early Earth (i.e. prior to the greening of landmasses). Accordingly, we analyse the Mojave River (California), one of the largest watercourses in the Great Basin of the western United States. We integrate discharge records with channel‐migration rates derived from dynamic time‐warping analysis and chronologically calibrated subsidence rates, thereby constraining the river's formative conditions. Our results reveal a slight downstream decrease in bankfull discharge on the Mojave River, rather than the downstream increase typically exhibited by perennial streams. Yet, the number of days per year during which the channel experiences bankfull or higher stages is roughly maintained along the river's length. Analysis of historical peak flood records suggests that the incidence of channel‐formative events responds to modulation in watershed runoff due to the precipitation in the river's headwaters over decades to centuries. Our integrated analysis finally suggests that, while maintaining hydraulic geometries that are fully comparable with many other rivers worldwide, ephemeral desert rivers akin to the Mojave are capable of generating a surprisingly wide range of depositional geometries in the stratigraphic record. © 2020 John Wiley & Sons, Ltd.

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“…Meandering rivers with muddy floodplains, in particular, are thought to have co-evolved with land plants and to only have become prevalent with the greening of the continents 109,110 , but the pre-life fluvial record of Earth is relatively poor 110 . In contrast, the surface of Mars hosts many meandering-river deposits 111 113 and quantify the rates of associated processes, such as lateral channel migration 114 . Thus, Martian river deposits might hold the key to interpreting the pre-Silurian rock record of Earth 113 , which, in turn, has direct implications for the duration of sediment storage within fluvial floodplains and, therefore, the pace of geochemical cycling and Earth's palaeoclimate 114,115 .…”

Section: Initiation Of Plate Tectonicsmentioning

confidence: 99%

“…In contrast, the surface of Mars hosts many meandering-river deposits 111 113 and quantify the rates of associated processes, such as lateral channel migration 114 . Thus, Martian river deposits might hold the key to interpreting the pre-Silurian rock record of Earth 113 , which, in turn, has direct implications for the duration of sediment storage within fluvial floodplains and, therefore, the pace of geochemical cycling and Earth's palaeoclimate 114,115 . Biological cycling dominates the distribution and availability of elements both critical and peripheral to life functions on Earth today, even creating new minerals 116 .…”

Section: Initiation Of Plate Tectonicsmentioning

confidence: 99%