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In areas characterized by many volcanoes, identifying the source of a deposit may not be trivial. This becomes much more complicated when looking for the source of a debris avalanche deposit (DAD), the common products of catastrophic volcanic edifice collapses. To overcome this problem, in this work a methodology is proposed based on the integration of texture features and areal distribution of the deposit, comparison between the petrography of the coarser clasts within the DAD and of the proximal products, grain-size analysis, and the volumetric estimations of the deposit and the volume missing from the volcanic edifice. This methodology has been tested to a DAD occurred near the city of Ibarra (Imbabura Province; Northern Ecuador), having a controversial source. Two main volcanic edifice are located in proximity of the DAD, the Cubilche volcano (3826 m.a.s.l.), located immediately south of and east of the colossal dormant Imbabura volcano. The former displays a sharp horseshoe shaped scar towards the north and inside this post-collapse edifice, that we name old Cubilche volcano (OCV), is located the young Cubilche volcano (YCV) that refilled a portion of the collapse scar and partially covered the southern flank of the OCV. Detailed knowledge of Cubilche volcano is critical because of its close proximity and interspersed activity with Imbabura volcano. In fact, Imbabura most recent edifice was built over the northwestern slope of the OCV and partially covered it. Recent studies linked the studied DAD to both Imbabura volcano as a product of its northern sector collapse, as well as neighboring Cubilche volcano. Our data points to Cubilche as the most likely source for this DAD. A perspective view of the shaded relief image of the present day OCV shows that the morphology of the volcano is well-preserved on its southern, eastern, and western flanks. This allows us to reconstruct the morphology of the OCV previous to the collapse through interpolation of elevation and altitude data of preserved flanks. A DEM of the present day topography was used for extrapolating the morphology. Using similar methodology, the post collapse base of the amphitheater was reconstructed by removing the relief of the present day YCV. The reconstructed topography of the OCV shows that it could have been a symmetric cone, reaching a maximum elevation of similar to 4100 m.a.s.l. with a lack volume of similar to 3.5 km(3). Based on this scenario, the deposit originated from the OCV main collapse should have a volume >3-3.5 km(3) in accordance to the volume calculated for the studied DAD. (C) 2018 Elsevier B.V. All rights reserved.
Combined structural and magnetotelluric investigation across the West Fault Zone in northern Chile
(2002)
The characterisation of the internal architecture of large-scale fault zones is usually restricted to the outcrop-based investigation of fault-related structural damage on the Earth's surface. A method to obtain information on the downward continuation of a fault is to image the subsurface electrical conductivity structure. This work deals with such a combined investigation of a segment of the West Fault, which itself is a part of the more than 2000 km long trench-linked Precordilleran Fault System in the northern Chilean Andes. Activity on the fault system lasted from Eocene to Quaternary times. In the working area (22°04'S, 68°53'W), the West Fault exhibits a clearly defined surface trace with a constant strike over many tens of kilometers. Outcrop condition and morphology of the study area allow ideally for a combination of structural geology investigation and magnetotelluric (MT) / geomagnetic depth sounding (GDS) experiments. The aim was to achieve an understanding of the correlation of the two methods and to obtain a comprehensive view of the West Fault's internal architecture. Fault-related brittle damage elements (minor faults and slip-surfaces with or without striation) record prevalent strike-slip deformation on subvertically oriented shear planes. Dextral and sinistral slip events occurred within the fault zone and indicate reactivation of the fault system. Youngest deformation increments mapped in the working area are extensional and the findings suggest a different orientation of the extension axes on either side of the fault. Damage element density increases with approach to the fault trace and marks an approximately 1000 m wide damage zone around the fault. A region of profound alteration and comminution of rocks, about 400 m wide, is centered in the damage zone. Damage elements in this central part are predominantly dipping steeply towards the east (70-80°). Within the same study area, the electrical conductivity image of the subsurface was measured along a 4 km long MT/GDS profile. This main profile trends perpendicular to the West Fault trace. The MT stations of the central 2 km were 100 m apart from each other. A second profile with 300 m site spacing and 9 recording sites crosses the fault a few kilometers away from the main study area. Data were recorded in the frequency range from 1000 Hz to 0.001 Hz with four real time instruments S.P.A.M. MkIII. The GDS data reveal the fault zone for both profiles at frequencies above 1 Hz. Induction arrows indicate a zone of enhanced conductivity several hundred meters wide, that aligns along the WF strike and lies mainly on the eastern side of the surface trace. A dimensionality analysis of the MT data justifies a two dimensional model approximation of the data for the frequency range from 1000 Hz to 0.1 Hz. For this frequency range a regional geoelectric strike parallel to the West Fault trace could be recovered. The data subset allows for a resolution of the conductivity structure of the uppermost crust down to at least 5 km. Modelling of the MT data is based on an inversion algorithm developed by Mackie et al. (1997). The features of the resulting resistivity models are tested for their robustness using empirical sensitivity studies. This involves variation of the properties (geometry, conductivity) of the anomalies, the subsequent calculation of forward or constrained inversion models and check for consistency of the obtained model results with the data. A fault zone conductor is resolved on both MT profiles. The zones of enhanced conductivity are located to the east of the West Fault surface trace. On the dense MT profile, the conductive zone is confined to a width of about 300 m and the anomaly exhibits a steep dip towards the east (about 70°). Modelling implies that the conductivity increase reaches to a depth of at least 1100 m and indicates a depth extent of less than 2000 m. Further conductive features are imaged but their geometry is less well constrained. The fault zone conductors of both MT profiles coincide in position with the alteration zone. For the dense profile, the dip of the conductive anomaly and the dip of the damage elements of the central part of the fault zone correlate. This suggests that the electrical conductivity enhancement is causally related to a mesh of minor faults and fractures, which is a likely pathway for fluids. The interconnected rock-porosity that is necessary to explain the observed conductivity enhancement by means of fluids is estimated on the basis of the salinity of several ground water samples (Archie's Law). The deeper the source of the water sample, the more saline it is due to longer exposure to fluid-rock interaction and the lower is the fluid's resistivity. A rock porosity in the range of 0.8% - 4% would be required at a depth of 200 m. That indicates that fluids penetrating the damaged fault zone from close to the surface are sufficient to explain the conductivity anomalies. This is as well supported by the preserved geochemical signature of rock samples in the alteration zone. Late stage alteration processes were active in a low temperature regime (<95°C) and the involvement of ascending brines from greater depth is not indicated. The limited depth extent of the fault zone conductors is a likely result of sealing and cementation of the fault fracture mesh due to dissolution and precipitation of minerals at greater depth and increased temperature. Comparison of the results of the apparently inactive West Fault with published studies on the electrical conductivity structure of the currently active San Andreas Fault, suggests that the depth extent and conductivity of the fault zone conductor may be correlated to fault activity. Ongoing deformation will keep the fault/fracture mesh permeable for fluids and impede cementation and sealing of fluid pathways.
Das Phänomen der Subduktion eines aktiven Spreizungszentrums an der Südspitze Südamerikas ist seit langem bekannt. Eine Vielzahl von geologischen Beobachtungen wurden mit diesem Phänomen in Verbindung gebracht, trotzdem ist der genaue Mechanismus der Beeinflussung des aktiven Kontinentalrandes weitgehend unbekannt. Die Zusammenhänge zwischen den Subduktionsprozessen und der Entwicklung der patagonischen Anden zwischen 47°S und 48°S stehen im Mittelpunkt der Untersuchungen. Um eine detaillierte zeitliche Auflösung der zugrunde liegenden Prozesse untersuchen zu können, wurde die Entwicklung der Vorlandsedimentation, die thermische Entwicklung und die Heraushebung der Oberkruste des andinen Orogens untersucht und diese in Bezug zur Subduktion des Chile-Rückens gesetzt. Im Bereich von 47°30′S wurden die synorogenen Vorlandsedimente der Santa Cruz Formation sedimentologisch untersucht. Diese fluviatilen Sedimente wurden in einem reliefarmen Vorlandgebiet durch häufige Rinnenverlagerung und dem Aufbau von Rinnenumlagerungsgürteln in Kombination mit assoziierten großräumigen Überflutungsablagerungen akkumuliert. Sie stehen in einem engen Zusammenhang mit der orogenen Entwicklung im andinen Liefergebiet. Dies spiegelt sich in dem nach oben gröber werdenden Zyklus der Santa Cruz Formation wider. Die magnetostratigraphischen Untersuchungen einer 270 m mächtigen Sequenz aus der Basis der Santa Cruz Formation, die mit 329 Einzelproben aus 96 Probenpunkten beprobt wurde, ergab 7 Umkehrungen der geomagnetischen Feldrichtung. Mit Hilfe der geomagnetischen Polaritätszeitskala (CANDE AND KENT, 1995) konnte der untersuchte Abschnitt der Santa Cruz Formation zwischen 16.2 und 18.5 Ma datiert werden. Als Träger der Sedimentations-Remanenz konnten überwiegend Pseudoeinbereichs-Magentitpartikel und untergeordnet Hämatitpartikel identifiziert werden. An drei Profilen der Santa Cruz Formation wurden aus Sandsteinlagen unterschiedlicher stratigraphischer Position detritische Apatite mit Hilfe der thermochronologischen Spaltspurmethode untersucht. Die thermisch nicht rückgesetzten, detritischen Apatite spiegeln das Auftreten unterschiedlicher Altersdomänen im Liefergebiet der Sedimente wider. In der Kombination mit den geochemischen Gesamtgesteinsuntersuchungen der Sedimente und den petrographischen Untersuchungen der Sandsteine, die ein überwiegend andesitisch-vulkanisch geprägtes Liefergebiet widerspiegeln, kann nachgewiesen werden, dass die Erosion im Liefergebiet um 16.5 Ma in tiefere, deformierte Krustensegmente einschneidet. Dies bedeutet, dass aufgrund der Denudation im andinen Orogen erste Sockelgesteinseinheiten in den Bereich der Abtragung gelangen und dass dieser Eintrag um 12 bis 10 Ma ein Volumen einnimmt, das zu signifikanten Änderungen der Gesamtgesteinsgeochemie der Vorlandsedimente führt. Die thermochronologische Untersuchung von Apatiten aus rezenten topographischen Höhenprofilen aus der Kernzone der patagonischen Anden im Bereich von 47°30′S zeigen den Beginn einer beschleunigten Heraushebung des Orogens um 7.5 Ma. Aus diesen Untersuchungen kann eine Denudationsrate im Zeitraum der letzen 7 bis 8 Ma von 600 bis 650 m/Ma abgeschätzt werden. Die Modellierung der Apatit-Spaltspurergebnisse zeigt eine signifikante Temperaturerhöhung im Zeitraum zwischen 12 und 8 Ma um 20 bis 30°C für diesen Krustenbereich, die mit der Subduktion des aktiven Chile-Rückens in diesem Bereich der Anden in Verbindung gebracht wird. Aus den gewonnen Daten kann ein Modell für die Entwicklung der patagonischen Anden seit dem frühen Miozän abgeleitet werden. In diesem Modell wird die orogene Entwicklung in den patagonischen Anden auf eine erhöhte Konvergenzrate zwischen der Nazca Platte und der Südamerikanischen Platte zurückgeführt, die für die Heraushebung und Denudation der Anden sowie für die damit verbundene Entwicklung im Vorlandbereich verantwortlich ist. Diese orogene Entwicklung wird in einer späten Phase durch die nordwärts wandernde Subduktion des aktiven Spreizungszentrums des Chile Rückens überprägt und beeinflusst. Das auf der Integration von geologischen, chronologischen sowie thermochronologischen Daten beruhende Modell kann zahlreiche geologische und geophysikalische Beobachtungen in diesem Bereich der südlichen Anden konsistent erklären.
Mountain ranges can fundamentally influence the physical and and chemical processes that shape Earths’ surface. With elevations of up to several kilometers they create climatic enclaves by interacting with atmospheric circulation and hydrologic systems, thus leading to a specific distribution of flora and fauna. As a result, the interiors of many Cenozoic mountain ranges are characterized by an arid climate, internally drained and sediment-filled basins, as well as unique ecosystems that are isolated from the adjacent humid, low-elevation regions along their flanks and forelands. These high-altitude interiors of orogens are often characterized by low relief and coalesced sedimentary basins, commonly referred to as plateaus, tectono-geomorphic entities that result from the complex interactions between mantle-driven geological and tectonic conditions and superposed atmospheric and hydrological processes. The efficiency of these processes and the fate of orogenic plateaus is therefore closely tied to the balance of constructive and destructive processes – tectonic uplift and erosion, respectively. In numerous geological studies it has been shown that mountain ranges are delicate systems that can be obliterated by an imbalance of these underlying forces. As such, Cenozoic mountain ranges might not persist on long geological timescales and will be destroyed by erosion or tectonic collapse. Advancing headward erosion of river systems that drain the flanks of the orogen may ultimately sever the internal drainage conditions and the maintenance of storage of sediments within the plateau, leading to destruction of plateau morphology and connectivity with the foreland. Orogenic collapse may be associated with the changeover from a compressional stress field with regional shortening and topographic growth, to a tensional stress field with regional extensional deformation and ensuing incision of the plateau. While the latter case is well-expressed by active extensional faults in the interior parts of the Tibetan Plateau and the Himalaya, for example, the former has been attributed to have breached the internally drained areas of the high-elevation sectors of the Iranian Plateau.
In the case of the Andes of South America and their internally drained Altiplano-Puna Plateau, signs of both processes have been previously described. However, in the orogenic collapse scenario the nature of the extensional structures had been primarily investigated in the northern and southern terminations of the plateau; in some cases, the extensional faults were even regarded to be inactive. After a shallow earthquake in 2020 within the Eastern Cordillera of Argentina that was associated with extensional deformation, the state of active deformation and the character of the stress field in the central parts of the plateau received renewed interest to explain a series of extensional structures in the northernmost sectors of the plateau in north-western Argentina. This study addresses (1) the issue of tectonic orogenic collapse of the Andes and the destruction of plateau morphology by studying the fill and erosion history of the central eastern Andean Plateau using sedimentological and geochronological data and (2) the kinematics, timing and magnitude of extensional structures that form well-expressed fault scarps in sediments of the regional San Juan del Oro surface, which is an integral part of the Andean Plateau and adjacent morphotectonic provinces to the east.
Importantly, sediment properties and depositional ages document that the San Juan del Oro Surface was not part of the internally-drained Andean Plateau, but rather associated with a foreland-directed drainage system, which was modified by the Andean orogeny and that became successively incorporated into the orogen by the eastward-migration of the Andean deformation front during late Miocene – Pliocene time. Structural and geomorphic observations within the plateau indicate that extensional processes must have been repeatedly active between the late Miocene and Holocene supporting the notion of plateau-wide extensional processes, potentially associated with Mw ~ 7 earthquakes. The close relationship between extensional joints and fault orientations underscores that 3 was oriented horizontally in NW-SE direction and 1 was vertical. This unambiguously documents that the observed deformation is related to gravitational forces that drive the orogenic collapse of the plateau. Applied geochronological analyses suggest that normal faulting in the northern Puna was active at about 3 Ma, based on paired cosmogenic nuclide dating of sediment fill units. Possibly due to regional normal faulting the drainage system within the plateau was modified, promoting fluvial incision.
We examined the relationship between the mechanical strength of the lithosphere and the distribution of seismicity within the overriding continental plate of the southern Central Andes (SCA, 29 degrees-39 degrees S), where the oceanic Nazca Plate changes its subduction angle between 33 degrees S and 35 degrees S, from subhorizontal in the north (<5 degrees) to steep in the south (similar to 30 degrees). We computed the long-term lithospheric strength based on an existing 3D model describing variations in thickness, density, and temperature of the main geological units forming the lithosphere of the SCA and adjacent forearc and foreland regions. The comparison between our results and seismicity within the overriding plate (upper-plate seismicity) shows that most of the events occur within the modeled brittle domain of the lithosphere. The depth where the deformation mode switches from brittle frictional to thermally activated ductile creep provides a conservative lower bound to the seismogenic zone in the overriding plate of the study area. We also found that the majority of upper-plate earthquakes occurs within the realm of first-order contrasts in integrated strength (12.7-13.3 log Pam in the Andean orogen vs. 13.5-13.9 log Pam in the forearc and the foreland). Specific conditions characterize the mechanically strong northern foreland of the Andes, where seismicity is likely explained by the effects of slab steepening.
Mafic magmatism in the Eastern Cordillera and Putumayo Basin, Colombia : causes and consequences
(2007)
The Eastern Cordillera of Colombia is mainly composed of sedimentary rocks deposited since early Mesozoic times. Magmatic rocks are scarce. They are represented only by a few locally restricted occurrences of dykes and sills of mafic composition presumably emplaced in the Cretaceous and of volcanic rocks of Neogene age. This work is focused on the study of the Cretaceous magmatism with the intention to understand the processes causing the genesis of these rocks and their significance in the regional tectonic setting of the Northern Andes. The magmatic rocks cut the Cretaceous sedimentary succession of black shales and marlstones that crop out in both flanks of the Eastern Cordillera. The studied rocks were classified as gabbros (Cáceres, Pacho, Rodrigoque), tonalites (Cáceres, La Corona), diorites and syenodiorites (La Corona), pyroxene-hornblende gabbros (Pacho), and pyroxene-hornblendites (Pajarito). The gabbroic samples are mainly composed of plagioclase, clinopyroxene, and/or green to brown hornblende, whereas the tonalitic rocks are mainly composed of plagioclase and quartz. The samples are highly variable in crystal sizes from fine- to coarse-grained. Accessory minerals such as biotite, titanite and zircon are present. Some samples are characterized by moderate to strong alteration, and show the presence of epidote, actinolite and chlorite. Major and trace element compositions of the rocks as well as the rock-forming minerals show significant differences in the geochemical and petrological characteristics for the different localities, suggesting that this magmatism does not result from a single melting process. The wide compositional spectrum of trace elements in the intrusions is characteristic for different degrees of mantle melting and enrichment of incompatible elements. MORB- and OIB-like compositions suggest at least two different sources of magma with tholeiitic and alkaline affinity, respectively. Evidence of slab-derived fluids can be recognized in the western part of the basin reflected in higher Ba/Nb and Sr/P ratios and also in the Sr radiogenic isotope ratios, which is possible a consequence of metasomatism in the mantle due to processes related to the presence of a previously subducted slab. The trace element patterns evidence an extensional setting in the Cretaceous basin producing a continental rift, with continental crust being stretched until oceanic crust was generated in the last stages of this extension. Electron microprobe analyses (EMPA) of the major elements and synchrotron radiation micro-X-ray fluorescence (μ-SRXRF) analyses of the trace element composition of the early crystallized minerals of the intrusions (clinopyroxenes and amphiboles) reflect the same dual character that has been found in the bulk-rock analyses. Despite the observed alteration of the rocks, the mineral composition shows evidences for an enriched and a relative depleted magma source. Even the normalization of the trace element concentrations of clinopyroxenes and amphiboles to the whole rock nearly follows the pattern predicted by published partition coefficients, suggesting that the alteration did not change the original trace element compositions of the investigated minerals. Sr-Nd-Pb isotope data reveal a large isotopic variation but still suggest an initial origin of the magmas in the mantle. Samples have moderate to highly radiogenic compositions of 143Nd/144Nd and high 87Sr/86Sr ratios and follow a trend towards enriched mantle compositions, like the local South American Paleozoic crust. The melts experienced variable degrees of contamination by sediments, crust, and seawater. The age corrected Pb isotope ratios show two separated groups of samples. This suggests that the chemical composition of the mantle below the Northern Andes has been modified by the interaction with other components resulting in a heterogeneous combination of materials of diverse origins. Although previous K/Ar age dating have shown that the magmatism took place in the Cretaceous, the high error of the analyses and the altered nature of the investigated minerals did preclude reliable interpretations. In the present work 40Ar/39Ar dating was carried out. The results show a prolonged history of magmatism during the Cretaceous over more than 60 Ma, from ~136 to ~74 Ma (Hauterivian to Campanian). Pre-Cretaceous rifting phases occurred in the Triassic-Jurassic for the western part of the basin and in the Paleozoic for the eastern part. Those previous rifting phases are decisive mechanisms controlling the localization and composition of the Cretaceous magmatism. Therefore, it is the structural position and not the age of the intrusions which preconditions the kind of magmatism and the degree of melting. The divergences on ages are the consequence of the segmentation of the basin in several sub-basins which stretching, thermal evolution and subsidence rate evolved independently. The first hypothesis formulated at the beginning of this investigation was that the Cretaceous gabbroic intrusions identified in northern Ecuador could be correlated with the intrusions described in the Eastern Cordillera. The mafic occurrences should mark the location of the most subsiding places of the large Cretaceous basin in northern South America. For this reason, the gabbroic intrusions cutting the Cretaceous succession in the Putumayo Basin, southern Colombia, were investigated. The results of the studies were quite unexpected. The petrologic and geochemical character of the magmatic rocks indicates subduction-related magmatism. K/Ar dating of amphibole yields a Late Miocene to Pliocene age (6.1 ± 0.7 Ma) for the igneous event in the basin. Although there is no correlation between this magmatic event and the Cretaceous magmatic event, the data obtained has significant tectonic and economic implications. The emplacement of the Neogene gabbroic rocks coincides with the late Miocene/Pliocene Andean orogenic uplift as well as with a significant pulse of hydrocarbon generation and expulsion.
Interactions and feedbacks between tectonics, climate, and upper plate architecture control basin geometry, relief, and depositional systems. The Andes is part of a longlived continental margin characterized by multiple tectonic cycles which have strongly modified the Andean upper plate architecture. In the Andean retroarc, spatiotemporal variations in the structure of the upper plate and tectonic regimes have resulted in marked along-strike variations in basin geometry, stratigraphy, deformational style, and mountain belt morphology. These along-strike variations include high-elevation plateaus (Altiplano and Puna) associated with a thin-skin fold-and-thrust-belt and thick-skin deformation in broken foreland basins such as the Santa Barbara system and the Sierras Pampeanas. At the confluence of the Puna Plateau, the Santa Barbara system and the Sierras Pampeanas, major along-strike changes in upper plate architecture, mountain belt morphology, basement exhumation, and deformation style can be recognized. I have used a source to sink approach to unravel the spatiotemporal tectonic evolution of the Andean retroarc between 26 and 28°S. I obtained a large low-temperature thermochronology data set from basement units which includes apatite fission track, apatite U-Th-Sm/He, and zircon U-Th/He (ZHe) cooling ages. Stratigraphic descriptions of Miocene units were temporally constrained by U-Pb LA-ICP-MS zircon ages from interbedded pyroclastic material.
Modeled ZHe ages suggest that the basement of the study area was exhumed during the Famatinian orogeny (550-450 Ma), followed by a period of relative tectonic quiescence during the Paleozoic and the Triassic. The basement experienced horst exhumation during the Cretaceous development of the Salta rift. After initial exhumation, deposition of thick Cretaceous syn-rift strata caused reheating of several basement blocks within the Santa Barbara system. During the Eocene-Oligocene, the Andean compressional setting was responsible for the exhumation of several disconnected basement blocks. These exhumed blocks were separated by areas of low relief, in which humid climate and low erosion rates facilitated the development of etchplains on the crystalline basement. The exhumed basement blocks formed an Eocene to Oligocene broken foreland basin in the back-bulge depozone of the Andean foreland. During the Early Miocene, foreland basin strata filled up the preexisting Paleogene topography. The basement blocks in lower relief positions were reheated; associated geothermal gradients were higher than 25°C/km. Miocene volcanism was responsible for lateral variations on the amount of reheating along the Campo-Arenal basin. Around 12 Ma, a new deformational phase modified the drainage network and fragmented the lacustrine system. As deformation and rock uplift continued, the easily eroded sedimentary cover was efficiently removed and reworked by an ephemeral fluvial system, preventing the development of significant relief. After ~6 Ma, the low erodibility of the basement blocks which began to be exposed caused relief increase, leading to the development of stable fluvial systems. Progressive relief development modified atmospheric circulation, creating a rainfall gradient. After 3 Ma, orographic rainfall and high relief lead to the development of proximal fluvial-gravitational depositional systems in the surrounding basins.
Geomorphology seeks to characterize the forms, rates, and magnitudes of sediment and water transport that sculpt landscapes. This is generally referred to as earth surface processes, which incorporates the influence of biologic (e.g., vegetation), climatic (e.g., rainfall), and tectonic (e.g., mountain uplift) factors in dictating the transport of water and eroded material. In mountains, high relief and steep slopes combine with strong gradients in rainfall and vegetation to create dynamic expressions of earth surface processes. This same rugged topography presents challenges in data collection and process measurement, where traditional techniques involving detailed observations or physical sampling are difficult to apply at the scale of entire catchments. Herein lies the utility of remote sensing. Remote sensing is defined as any measurement that does not disturb the natural environment, typically via acquisition of images in the visible- to radio-wavelength range of the electromagnetic spectrum. Remote sensing is an especially attractive option for measuring earth surface processes, because large areal measurements can be acquired at much lower cost and effort than traditional methods. These measurements cover not only topographic form, but also climatic and environmental metrics, which are all intertwined in the study of earth surface processes. This dissertation uses remote sensing data ranging from handheld camera-based photo surveying to spaceborne satellite observations to measure the expressions, rates, and magnitudes of earth surface processes in high-mountain catchments of the Eastern Central Andes in Northwest Argentina. This work probes the limits and caveats of remote sensing data and techniques applied to geomorphic research questions, and presents important progress at this disciplinary intersection.