Rate and processes of river network rearrangement during incipient faulting: The case of the Cahabon River, Guatemala

Brocard, Gilles; Willenbring, Mark L.; Suski, B.; Audra, Philippe; Authémayou, Christine; Cosenza-Muralles, B; Morán‐Ical, Sergio; Demory, François; Rochette, P.; Vennemann, Torsten; Holliger, Klaus; Teyssier, Christian

doi:10.2475/05.2012.01

Cited by 26 publications

(51 citation statements)

References 101 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As such, knickpoint propagation is often simply modeled as:

C = ψ A^{b}

where C is the knickpoint lip propagation celerity (m yr −1 ), A is the drainage area upstream of the knickpoint lip (m 2 ), ψ is the retreat efficiency (m 1−2 b yr −1 ), and b is a nondimensional constant. Drainage area dependency tends to be higher along fast‐migrating knickpoints, with b > 1 [e.g., Bishop et al ., ; Crosby and Whipple , ], than along slowly migrating ones, with b ≤ 0.5 [e.g., Weissel and Seidl , ; Berlin and Anderson, ; Brocard et al ., ], suggesting that fluvial processes are more effective than other processes at propagating knickpoints. We simulated knickpoint migration along the six major branches of Río Blanco starting at an initiation point defined in section 4.2 (Figure a).…”

Section: Processes Governing Slow Knickpoint Retreatmentioning

confidence: 99%

“…This value, b = 0.25, lies halfway between the theoretical value of b = 0.5 expected when celerity is controlled by unit stream power and the value b = 0 expected when celerity is independent from fluvial erosion (Figure a, AD model). Using our estimated age of initiation of 4.2 ± 0.3 Myr, the best fit retreat efficiency is 2.5 ± 0.2 · 10 −5 m 0.5 yr −1 , about 10 times lower than the retreat efficiency found over steeply bedded shales at similar b values and drainage areas in the subtropical belt [ Brocard et al ., ].…”

Section: Processes Governing Slow Knickpoint Retreatmentioning

confidence: 99%

See 1 more Smart Citation

Relict landscape resistance to dissection by upstream migrating knickpoints

Brocard

Willenbring

Miller

et al. 2016

J. Geophys. Res. Earth Surf.

View full text Add to dashboard Cite

Expanses of subdued topographies are common at high elevation in mountain ranges. They are often interpreted as relict landscapes and are expected to be replaced by steeper topography as erosion proceeds. Preservation of such relict fragments can merely reflect the fact that it takes time to remove any preexisting topography. However, relict fragments could also possess intrinsic characteristics that make them resilient to dissection. We document here the propagation of a wave of dissection across an uplifted relict landscape in Puerto Rico. Using 10Be‐26Al burial dating on cave sediments, we show that uplift started 4 Ma and that river knickpoints have since migrated very slowly across the landscape. Modern detrital 10Be erosion rates are consistent with these long‐term rates of knickpoint retreat. Analysis of knickpoint distribution, combined with visual observations along the streambeds, indicates that incision by abrasion and plucking is so slow that bedrock weathering becomes a competing process of knickpoint retreat. The studied rivers flow over a massive stock of quartz diorite surrounded by an aureole of metavolcanic rocks. Earlier studies have shown that vegetation over the relict topography efficiently limits erosion, allowing for the formation of a thick saprolite underneath. Such slow erosion reduces streambed load fluxes delivered to the knickpoints, as well as bed load grain size. Both processes limit abrasion. Compounding the effect of slow abrasion, wide joint spacing in the bedrock makes plucking infrequent. Thus, the characteristics of the relict upstream landscape have a direct effect on stream incision farther downstream, reducing the celerity at which the relict, subdued landscape is dissected. We conclude that similar top‐down controls on river incision rate may help many relict landscapes to persist amidst highly dissected topographies.

show abstract

“…As such, knickpoint propagation is often simply modeled as:

C = ψ A^{b}

Section: Processes Governing Slow Knickpoint Retreatmentioning

confidence: 99%

Section: Processes Governing Slow Knickpoint Retreatmentioning

confidence: 99%

Relict landscape resistance to dissection by upstream migrating knickpoints

Brocard

Willenbring

Miller

et al. 2016

J. Geophys. Res. Earth Surf.

View full text Add to dashboard Cite

show abstract

“…As a result, evidence for migration has often been sought after in the stratigraphic record of the sediment sinks into which drainages terminate (e.g. Horton and DeCelles, 2001;Clark et al, 2004;Brocard et al, 2012;Prince and Spotila, 2013;Simon-Labric et al, 2014;Morriss and Wegmann, 2016). However, such proxies are indirect, lack spatial resolution, and are hard to acquire.…”

Section: Introductionmentioning

confidence: 99%

Unraveling the roles of asymmetric uplift, normal faulting and groundwater flow to drainage rearrangement in an emerging karstic landscape

Authémayou

Brocard

Delcaillau

et al. 2018

Earth Surf Processes Landf

View full text Add to dashboard Cite

Landscape adjustment to tectonic, lithologic and climatic forcing leads to drainage reorganization and migration of divides. The respective contribution of these forcings, especially on carbonate landscapes is not well defined. Here, we have addressed this issue by combining field observations, satellite image interpretation and digital elevation model (DEM) quantitative analysis to assess drainage response to spatially heterogeneous rainfall, asymmetric uplift, and normal faulting on an emerging carbonated platform (Sumba Island, Indonesia). We map geomorphic markers of fluvial dynamics and drainage rearrangement and compute a χ parameter that incorporates the contributions of unevenly distributed precipitation and asymmetric uplift to estimate erosional disequilibrium across drainage divides. We find that asymmetric emergence of Sumba Island created an initial parallel drainage, asymmetric across a divide that propagates landwards. Soon after establishing itself on the emerging slopes this drainage was disturbed by normal faulting, which has become the main force driving drainage rearrangement. Vertical offsets across normal fault scarps first triggered aggradation within valleys over the hanging walls, and then disconnected upstream reaches from downstream reaches, leading to the formation of wind gaps atop the fault scarps and upstream perched sedimentary basins. The defeat of rivers by growing fault scarps was catalysed by the possibility for surface water to be rerouted near the fault scarps into underground water networks inside the underlying carbonates. At the end of the process, the opposite drainage across the main water divide captured the struggling drainage. Capture mechanisms include initial groundwater capture of the perched alluvial aquifers, followed by ground sapping at the head of the opposite drainage and surface stream diversion by avulsion. Finally, normal faulting is the main driving force of drainage rearrangement allowing avulsion and karstic rerouting whereas asymmetric uplift and climate forcings have shown a low efficiency. The role of karstification is more ambiguous, catalysing or inhibiting drainage rearrangement. Copyright © 2018 John Wiley & Sons, Ltd.

show abstract

“…Various mechanisms have been proposed to drive drainage reorganization in the Alps [Ziegler and Fraefel, 2009;Schlunegger and Mosar, 2011] and elsewhere [Bishop, 1995;Brocard et al, 2012]. Such physical mechanisms include tectonic activity, ice sheets, landslides, and groundwater processes.…”

Section: Driving Mechanismsmentioning

confidence: 99%

“…This pulse of erosion is also propagated upstream through both the captured and original river basins. Few studies have quantified the rates and magnitudes of fluvial erosion associated with river capture events [e.g., Gunnell and Harbor, 2010;Schlunegger and Mosar, 2011;Prince et al, 2011;Andrews et al, 2012;Brocard et al, 2012], and we are not aware of studies that have explored the implications of drainage capture for landscape evolution with a numerical model.…”

Section: Introductionmentioning

confidence: 99%

High magnitude and rapid incision from river capture: Rhine River, Switzerland

et al. 2013

View full text Add to dashboard Cite

[1] Landscape evolution is controlled by the development and organization of drainage basins. As a landscape evolves, drainage reorganization events can occur via river capture or piracy, whereby one river basin grows at the expense of another. The river downstream of a capture location will generate a transient topographic response as the added water discharge increases sediment transport and erosion efficiency. This erosional response will propagate upstream through both the captured and original river basins. Here we focus on quantifying the impact of drainage reorganization along the Rhine/Aare River system (~45,000 km 2 ) during the late Pliocene/early Pleistocene, where gravel remnants indicate total incision of~650 m during the last~4.2 Myr in the region of the recent Aare-Rhine confluence. We develop a numerical model of drainage capture to quantify the range of possible magnitudes of erosion and the transient river response resulting from the reorganization of the Rhine River. The model accounts for both fluvial incision and sediment transport. Our model estimates 400-800 m of river elevation change (lowering profiles) during the last~4 Myr due to river capture events, providing an important component to the recent exhumation budget of the Swiss Alpine Foreland. The model indicates a rapid response to capture events (re-equilibration timescale of~1 Myr). The predicted incision magnitudes are consistent with incision measured from the elevation of Pliocene and early Pleistocene river gravels, suggesting that across northern Switzerland, a significant amount of incision can be explained by drainage reorganization.

show abstract

Rate and processes of river network rearrangement during incipient faulting: The case of the Cahabon River, Guatemala

Cited by 26 publications

References 101 publications

Relict landscape resistance to dissection by upstream migrating knickpoints

Relict landscape resistance to dissection by upstream migrating knickpoints

Unraveling the roles of asymmetric uplift, normal faulting and groundwater flow to drainage rearrangement in an emerging karstic landscape

High magnitude and rapid incision from river capture: Rhine River, Switzerland

Contact Info

Product

Resources

About