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We perform a systematic and detailed study of the 14C and 14C‐10Be dating systems for meteorite terrestrial ages. Physical model calculations indicate that neither the 14C production rates nor the 14C/10Be production rate ratios are constant enough to be reasonably approximated by average values. By using simple averages, one introduces a significant size‐dependent bias into the database for meteorite terrestrial ages. By combining modeled 14C production rates and 14C/10Be production rate ratios with (22Ne/21Ne)cos ratios and assuming ~80% ablation losses, relatively easy to use correlations of 14C production rates and 14C/10Be production rate ratios as a function of (22Ne/21Ne)cos are established. The new correlations enable the determination of terrestrial ages that are more accurate than ages based solely on average values for 14C and/or 14C/10Be. We validate the model predictions by measuring 14C activity concentrations, 14C/10Be production rate ratios, 21Necos concentrations, and (22Ne/21Ne)cos ratios in four recently fallen meteorites: Mt. Tazerzait, Boumdeid (2011), Bensour, and SaU 606. The experimental data confirmed the model predictions, although the available data are insufficient to be conclusive. More data from freshly fallen meteorites are needed for validating the model predictions for different chondrite sizes and chondrite types. [ABSTRACT FROM AUTHOR]

This study provides a comprehensive characterization of various hydrothermal systems in Southern Peru ranging from the faulted Precordillera's steep topography up to the volcanic High Cordillera (>4,000 m asl). The objective is to investigate thermal anomalies that may potentially serve as new geothermal resources. Our integrated approach combines: (a) geochemistry from 14 hot springs sampled throughout the Tacna region, and (b) 3D numerical modeling of coupled groundwater and heat transfer considering topography and faults embedded in homogeneous permeability. Water and gas analysis indicates that the springs located near volcanoes discharge Na‐K‐Cl waters with high temperatures (>87°C), high Total Dissolved Solid concentrations (TDS >3,452 mg/L), and free gases dominated by CO2 (>90 vol%). Springs located along the regional faults in the Precordillera discharge Ca‐SO4 and Na‐K‐Cl waters with moderate temperatures (27–53°C), intermediate TDS concentrations (464–2,458 mg/L), radiocarbon ages between 1.4 and 7.9 kyr, and free gases dominated by N2 (>95 vol%). The Aruma springs, which are located at the transition between the High and the Precordillera, display intermediate characteristics. Numerical models accurately replicate the locations and temperatures of the fault‐related springs only for permeable faults (>10−14 m2), revealing the creation of 100‐km long thermal plumes along faults, locally rising up the 150°C‐isotherm to about ∼1,000 m below the surface. This approach clearly distinguishes the spring origins, which are volcanic in High Cordillera and tectonic in Precordillera. Moreover, we highlight that steep topographic gradient and permeable reverse faults in the Andean forearc may generate considerable thermal anomalies, opening perspectives for the geothermal exploration. Plain Language Summary: Geothermal energy is an essential part of the transition to green energies. It consists of using the Earth' natural heat to generate electricity or provide direct heating. In the Peruvian Andes there is significant geothermal potential near volcanoes that constitute an efficient heat source. However, these are distant from many of the population hubs, mostly located along the Pacific Coast. In the Tacna region, Southern Peru, we observe hot springs aligned along faults near the city. We hypothesize that these faults act as pipes for the hot fluids making them suitable for geothermal energy extraction. The geochemical compositions of various hot springs in the region are compared with 3D numerical models simulating hydrothermal flows. We found that springs along volcanoes and those along faults have different geochemical signatures, evidencing different subsurface pathways. Numerical models accurately replicate the positions and temperatures of the observed and sampled hot springs and reveal significant thermal anomalies around compressional faults. Our findings open up promising perspectives for the geothermal exploration in the Andean forearc. Key Points: The geochemical properties of Southern Peru's hot springs are influenced by their spatial correlation with volcanic or tectonic featuresBy combining permeable faults and topography, 3D hydrothermal modeling replicates the temperatures and locations of observed springsDetection of regional topography‐driven thermal plumes along faults in the Andean forearc opens perspectives for geothermal exploration [ABSTRACT FROM AUTHOR]

This study examines the suitability of the authigenic 10Be/9Be dating method to the dating of the deposits of an incising river, taking as an example the Nová Vieska river terrace, which accumulated during the neotectonic inversion of the Danube Basin (western Slovakia). The succession was formed by a wandering river with minor preservation of proximal floodplain muds. The frequent occurrence of mud intraclasts reflects significant input of eroded material from underlying, older successions. The ages of 13 authigenic 10Be/9Be dating samples formed three groups: (1) samples from below the base of the river terrace yielded dates of ~4.13–3.70 Ma (including uncertainties); (2) muddy intraclasts from the river terrace gave an age range of ~2.79–1.96 Ma; and (3) in situ muddy layers had ages in the range of ~1.91–1.39 Ma. The large mammal fossil assemblage from channel thalweg deposits yielded a biostratigraphic age of ~3.6–2.2 Ma, matching the age of intraclasts, and thus emphasising the redeposited origin of those fossils. The relatively wide range of authigenic 10Be/9Be dating ages is interpreted as a result of the redeposition of mud from older strata on three scales: decimetre‐scale intraclasts, millimetre‐scale rip‐up clasts mixed into the newly formed beds, and formation of two authigenic rims with different age and 10Be/9Be records around individual particles. Considering these observations, an age range of in situ layers of ~1.91–1.39 Ma is proposed as the depositional age of the river terrace, with the most probable age falling within the most recent part of this interval. The effect of redeposition is thus shown to be potentially limiting to the application of authigenic 10Be/9Be dating to incising rivers, and stands in marked contrast to aggrading river settings, where redeposition of older sediments is limited and the degree of 10Be/9Be variability is low. [ABSTRACT FROM AUTHOR]

Through the investigation of terrestrial ages of meteorites from Oman, we aim to better understand the time scales of meteorite accumulation and erosion in Oman and the meteorite flux in the past. Here, we present 14C and 14C‐10Be terrestrial ages of seven ordinary chondrite strewn fields and two unpaired single meteorites from the Sultanate of Oman. After critical evaluation of multiple data for each strewn field, we propose "best estimate terrestrial ages," typically based on 14C/10Be. For objects for which complex irradiation histories are known or suspected, terrestrial ages were calculated solely using 14C. The best estimate strewn field ages range from 8.1 ± 3.0 ka (SaU 001) to 35.2 ± 5.1 ka (Dho 005). Including two previously dated strewn fields, the mean and median age of nine Oman strewn fields is 15.9 ± 12.3 and 13.6 ka, respectively. The new data show a general good agreement with data previously obtained in a different laboratory, and we observe a similar general correlation between strewn field ages and mean weathering grade as in previous work based on individual meteorites. Weathering degree W4 is reached for dated samples after 20–35 ka. While the age statistics of strewn fields does not show the previously observed lack of young events, the low abundance of young (0–5 ka) individual meteorites as compared with older (~20 ka) meteorites is confirmed by our data and remains unexplained. [ABSTRACT FROM AUTHOR]

We analyze major landforms of the Lut Desert in Iran to provide a comprehensive source‐to‐sink picture of aeolian systems on time scales from decades to millions of years. We map the modern sandflows, along which we evaluate the volume and chronology associated with the excavation of mega‐yardangs upwind and the formation of giant dunes downwind. Sediment discharges deduced from long‐term erosion and deposition are of the same order of magnitude (105–106 m3 yr−1) as short‐term and medium‐term sand discharges derived from wind data and dune morphodynamics. At the scale of the internal aeolian sediment‐routing system of the Lut, we establish an overall sediment budget constrained by the joint development of the erosional and depositional landforms. Our findings thus quantify the geomorphic controls of aeolian processes on arid landscapes at multiple length and time scales, while providing information on mass exchanges between continents and atmosphere. Plain Language Summary: Wind‐blown sand and dust emissions shape singular landscapes in arid environments and globally impact climate, life, and human activities. Nevertheless, the contributions of aeolian processes to the evolution of continental surfaces and to their mass exchanges with oceans and the atmosphere are still subject to considerable uncertainties. Compared to sediment transport in rivers, this is because wind transport is not associated with a well‐identified channel network that directly links sand and dust production (source) to accumulation (sink) areas. The Lut Desert in Iran is nested in a closed topographic depression which provides an appropriate context to investigate the work of the wind. Spectacular landforms called mega‐yardangs and giant dunes are used together with modern wind data to map and quantify sandflows at different time scales. These sandflows are consistent with each other from decades to millions of years and allow to estimate the amount of sediments transported across the Lut Desert or emitted into the atmosphere. These estimates are not only important for the management of terrestrial drylands, but they can also provide information about the past evolution of planetary bodies dominated by aeolian processes such as Mars or Titan. Key Points: The wind regimes within the Lut Desert create an internal aeolian sediment‐routing systemThe joint development of erosional and depositional landforms are consistent with modern sandflowsSource‐to‐sink aeolian fluxes are of the same order of magnitude from decades to millions of years [ABSTRACT FROM AUTHOR]

The timing of mountain glacier fluctuations is poorly constrained in some parts of Greenland during the Late Holocene. We present 31 10Be cosmic‐ray exposure ages (CRE) of boulders collected from three mountain glacier moraines located in the Tasilap valley, in southeastern Greenland, and 10 10Be CRE ages from one mountain glacier in the Isortup valley, in southern Greenland. For the first time in these areas, mountain glacier fluctuations are documented from moraine CRE for the Late Holocene period. Several glacier advances during the Late Holocene are revealed with exposure ages ranging from 3.90±0.26 to 0.4±0.04 ka. Moraines of three of the four glaciers investigated, dated to 3.75±0.13 ka (n = 3), 3.3±0.19 ka (n = 2) and 2.87±0.13 ka (n = 3), show a common timing of the largest glacier expansion during the Late Holocene. Evidence of at least one individual moraine deposited at ~1.2 ka was found on all glaciers. Finally, the most recent period of glacial advance during the Late Holocene is documented by one glacier in each valley at ~0.66–0.70 ka. The maximum glacier extent at ~3 ka differs from the Late Holocene glacier maximum extent usually reported during the Little Ice Age in east Greenland based on moraine dating and lake sediments. We suggest that the combination of a stronger East Greenland Current and a weaker Irminger Current, potentially associated with increased sea‐ice concentration, superimposed on the long‐term decrease in summer insolation during the Late Holocene could be responsible for this large glacial advance at ~3 ka in southern and southeastern Greenland. [ABSTRACT FROM AUTHOR]

We measured noble gas concentrations and isotopic ratios (He, Ne, and Ar isotopes) in six recent ordinary chondrite falls: Mangui (L6), Viñales (L6), Ozerki (L6), Tamdakht (H5), Kheneg Ljouâd (LL5/6), and Katol (L6). Among them, the three L6 chondrites Mangui, Viñales, and Ozerki fell in only a few months' interval; their apparent similar petrographic and mineralogic characteristics might indicate source crater pairing. To test this hypothesis, we have investigated those meteorites for their cosmic ray exposure (CRE) histories, using the cosmogenic noble gases 3He, 21Ne, and 38Ar. We systematically (re)calculated the CRE ages as well as the gas retention ages of these meteorites. The CRE age of the Mangui is, based on noble gases, <1 Ma, which is unusually short for an L chondrite. Indeed, the range of exposure ages for L chondrites is generally distributed between ˜1 and ˜60 Ma, with major peaks occurring around ˜5, ˜30, and ˜40 Ma. In addition, the cosmogenic 3Hecos data of two Mangui duplicates are consistent with a remarkably high loss of helium by diffusion due to heating by solar radiation. Such a short parent body‐Earth transfer time (<1 Ma) can be explained by a delivery from an Earth‐crossing object. Regarding the other L6 chondrites, Viñales has a nominal CRE age of ˜9.4 Ma, whereas the Ozerki meteorite has a nominal CRE age of ˜1.2 Ma, which is consistent with Korochantseva et al. (2019). Based on their CRE ages as well as on their gas retention ages, it appears that none of these three recent L6 chondrite falls are source crater paired, and therefore, all three originate from different meteoroids. The nominal exposure ages of Tamdakht, Kheneg Ljouâd, and Katol are ˜3.2, ˜11, and ˜30 Ma, respectively, and are consistent with identified age peaks on the exposure age histogram of H, LL, and L chondrites, respectively. The nominal CRE age of Tamdakht is consistent with previous observations for H chondrites and implies that they are dominated by small impact events occurring in several parent bodies. [ABSTRACT FROM AUTHOR]

Patterned‐ground landforms represent the most common phenomenon of periglacial environment, and their large sorted forms belong to the few morphological indicators of past permafrost distribution. The relic forms of patterned ground are widespread on high‐elevated surfaces in the central European uplands, providing the evidence of regional periglacial conditions in the last glacial period. However, the timing of these landforms, as well as their potential for paleoclimate reconstructions, has remained unexplored. In this paper, we present 10Be exposure ages from the large sorted polygons sampled at four sites in the Sudetes Mountains, the highest part of the central European uplands. These results indicate that these landforms started to form at the end of Marine Isotope Stage 3, and the main phase of their formation occurred between 30 and 20 ka. This research confirms the hypothesis of sorted patterned‐ground formation within the last (Weichselian) glacial stage (110.6–11.7 ka) and suggests that earlier‐sorted features are not preserved in the Sudetes. The recognized period of enhanced periglacial activity coincides with a prominent cold interval identified earlier in both regional and northern‐hemispheric proxy records. [ABSTRACT FROM AUTHOR]

Despite an increasing interest in Greenlandic mountain glaciers over recent decades, their evolution during the Lateglacial and Holocene still needs to be better constrained. Here we present 25 10Be cosmic‐ray exposure (CRE) ages of boulders collected on moraines from three glaciers located on Clavering Island (northeastern Greenland). CRE ages span 16.29±0.79 to 0.37±0.05 ka and reveal three periods of moraine formation during the Lateglacial, the Early and the Late Holocene. Data show a multi‐modal distribution of the ages during the Lateglacial with exposure ages spanning from 16.29±0.79 to 12.31±1.3 ka. At least two glaciers experienced a greater expansion at the beginning of the Holocene than at the end of the Holocene, dated to 11.3±0.3 and 10.8±0.6 ka, respectively. At the end of the Holocene, glacial advances occurred during the Dark Ages Cold Period and during the Little Ice Age (LIA), synchronous with glacial advances documented in nearby lake sediments. This new CRE chronology highlights that the LIA extent is not the largest glacier advance in the Late Holocene in Clavering Island. This broadly corresponds with other mountain glaciers of western and northern Greenland, and does not appear to reflect northern high latitude summer insolation that would suggest progressive temperature decrease, but instead mimics recent regional continental temperature reconstructions that show a long term warming driven by different forcing. [ABSTRACT FROM AUTHOR]

Estimating the extent and age of the last glacial maxima as well as the chronology of glacial recessions in various environmental contexts is key to source‐to‐sink studies and paleoclimate reconstructions. The Argentera‐Mercantour massif is located at the transition between the Alps and the Mediterranean Sea, therefore, its deglaciation chronology can be compared to the sediment budget of the Var River basin. Based on 13 new cosmic‐ray exposure (CRE) beryllium‐10 (10Be) datings performed on moraines and polished crystalline bedrocks and 22 reassessed 10Be CRE ages from similar altitude nearby steep basement surfaces, and from a lake sediment core, we can constrain the deglaciation chronology of the Argentera‐Mercantour massif. These data allow for the first time to fully reconstruct the deglaciation history at the scale of the entire massif in agreement with a major glacier recession at c. 15 ka, at the onset of Bølling transition between the Oldest and Older Dryas. Main deglaciation of the upper slopes [2700–2800 m above sea level (a.s.l.)] occurred after the Last Glacial Maximum (LGM) at 20.8–18.6 ka, followed by the main deglaciation of the lower slopes (2300 m a.s.l.) at 15.3–14.2 ka. Finally, the flat polished surfaces above 2600 m a.s.l. and the zones confined within narrow lateral valleys were likely affected by progressive ice melting of remaining debris covered glaciers and moraine erosion following the Younger Dryas re‐advance stage between 12 and 8–9 ka. At lower elevations, the Vens Lake located at 2300 m a.s.l., allows evidence of the onset of lake sedimentation at c. 14 ka and a transition towards a vegetated environment that mainly occurred before 8 ka. Moraine final stabilization at 5 ka might reflect denudation acceleration during the Holocene humid phase. This contribution reveals a glacier–climate relationship more sensitive to warming phases in the southern Alps highlighted by a major decrease of glaciers after c. 15 ka. This major deglaciation is correlated with a 2.5‐fold decrease of sediment discharge of rivers into the Mediterranean Sea. © 2019 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The recent tectonics of the arid northern Chile Andean western forearc is characterized by trench‐parallel normal faults within the Atacama Fault System (AFS). Since the 1995‐Mw 8.1 Antofagasta earthquake, the mechanism driving this recent and localized extension is considered to be associated with the seismic cycle within the subduction zone. Analyzing morphotectonic patterns along these faults allows examining the seismic potential associated with the subduction zone. Using field Digital Elevation Models and in situ‐produced cosmogenic 10Be, we determined a 0.2 mm/a long‐term slip rate along the Mejillones Fault, one of the most prominent structures within the AFS. This result suggests that the AFS corresponds to slow slip rate faults despite the rapid subduction context. However, the size of coseismic slips observed along the AFS faults suggests that larger subduction earthquakes (Mw > 8.1) may occur episodically in the area. [ABSTRACT FROM AUTHOR]

We describe the geological, morphological, and climatic settings of two new meteorite collections from Atacama (Chile). The 'El Médano collection' was recovered by systematic on-foot search in El Médano and Caleta el Cobre dense collection areas and is composed of 213 meteorites before pairing, 142 after pairing. The 'private collection' has been recovered by car by three private hunters and consists of 213 meteorites. Similar to other hot desert finds, and contrary to the falls and Antarctica finds, both collections show an overabundance of H chondrites. A recovery density can be calculated only for the El Médano collection and gives 251 and 168 meteorites larger than 10 g km−2, before and after pairing, respectively. It is by far the densest collection area described in hot deserts. The Atacama Desert is known to have been hyperarid for a long period of time and, based on cosmic-ray exposure ages on the order of 1-10 Ma, to have been stable over a period of time of several million years. Such a high meteorite concentration might be explained invoking either a yet unclear concentration mechanism (possibly related to downslope creeping) or a previously underestimated meteorite flux in previous studies or an average terrestrial age over 2 Myr. This last hypothesis is supported by the high weathering grade of meteorites and by the common terrestrial fragmentation (with fragments scattered over a few meters) of recovered meteorites. [ABSTRACT FROM AUTHOR]

The dextral Longriba fault system (LFS), ~300 km long and constituting of two fault zones, has recently been recognized as an important structure of the eastern Tibetan plateau (Sichuan province), as it accommodates a significant amount of the deformation induced by the ongoing Indo-Asian collision. Although previous paleoseismological investigations highlighted its high seismogenic potential, no systematic quantification of the dextral displacements along the fault system has been undertaken so far. As such information is essential to appraise fault behavior, we propose here a first detailed analysis of the segmentation of the Longriqu fault, the northern fault zone of the LFS, and an offset inventory of morphological features along the fault, using high-resolution Pleiades satellite images. We identify six major segments forming a mature fault zone. Offsets inventory suggests a characteristic coseismic displacement of ~4 m. Two alluvial fans, with minimum ages of 6.7 and 13.2 ka, respectively displaced by 23 ± 7 m and 40 ± 5 m, give an estimate of the maximal horizontal slip rate on the Longriqu fault of 3.2 ± 1.1 mm yr−1. As a result, a minimum ~1340 year time interval between earthquakes is expected. [ABSTRACT FROM AUTHOR]

The Doruneh Fault System (DFS) is one of the major active strike-slip faults in the Arabia-Eurasia collision zone. Despite its geological activity, no large ( M ≥ 6.5) historical or instrumental earthquakes have been recorded along it. To date, the rate and distribution of slip, as well as the seismic behavior of the DFS, have been unknown. We reconstructed 67 geomorphic offsets recorded by three successive alluvial abandonment surfaces (Q1, Q2, and Q3) displaced along the western (WFZ) and central (CFZ) fault zones. The determined ages of ~12, ~36, and ~120 ka, using in situ-produced 10Be and 36Cl cosmogenic nuclides for theses surfaces, allowed to estimate three sets of individual left-lateral slip rates and consequently to describe the spatiotemporal distribution of slip along the CFZ and WFZ. The slip rates averaged over time intervals of ~36 and ~120 ka reveal variable slip rates along length but similar slip rates at a point with a maximum rate of ~8.2 mm/yr. During the Holocene, however, the fault slip behavior appears more complex, with a maximum rate of ~5.3 mm/yr. The CFZ is divided into two ~4 km apart segments, with symmetrical slip distributions relative to a persistent boundary, which has not been ruptured over the last ~12 ka. The maximum length of seismic fault segments varies from 70 to 100 km, which could produce earthquakes with a magnitude of Mw 7.2-7.4. This emphasizes the necessity of segmentation models for long strike-slip faults that may not necessarily rupture along their whole length during a single earthquake. [ABSTRACT FROM AUTHOR]

It is still disputed whether very old archaeological and palaeontological remains found in the Belle- Roche palaeocave (eastern Belgium) pertain to the Early (∼1 Ma) or Middle (∼0.5 Ma) Pleistocene. Here, in situ-produced cosmogenic 10 Be concentrations from a depth profile in nearby sediments of the Belle- Roche terrace ( Amblève Main Terrace level) are used as an indirect solution of this chronological issue. The distribution of 10 Be concentrations in the upper 3 m of this profile displays the theoretically expected exponential decrease with depth. Assuming a single exposure episode, we obtain a best fit age of 222.5±31 ka for the time of terrace abandonment. However, below 3 m, the 10 Be concentrations show a marked progressive increase with depth. This distinctive cosmogenic signal is interpreted as the result of slow aggradation of the fluvial deposits over a lengthy interval. Modelling of the whole profile thus suggests that the onset of the terrace formation occurred at around 550 ka, with a sediment accumulation rate of ∼20 mm ka−1. Based on two slightly different reconstructions of the geomorphic evolution of the area and a discussion of the temporal link between the cave and Main Terrace levels, we conclude that the fossil-bearing layers in the palaeokarst pertain most probably to MIS 14-13, or possibly MIS 12-11. This age estimate for the large mammal association identified in the Belle- Roche palaeokarst and the attribution to MIS 14-13 of a similar fauna found in the lowermost fossiliferous layers of the Caune de l' Arago ( Tautavel) are in mutual support. Our results therefore confirm the status of the Belle- Roche site as a reference site for the Cromerian mammal association in NW Europe. [ABSTRACT FROM AUTHOR]

The Serra do Mar escarpment, located along the southeastern coast of Brazil, is a high-elevation passive margin escarpment. This escarpment evolved from the denudation of granites, migmatites and gneisses. The granites outcrop in the form of a ridge along the escarpment crest, due to its differential erosion ('sugarloaf' hills) from the surrounding lithologies. Several studies suggest that the passive margin escarpments are actively retreating toward the interior of the continent. However, no prior study has calculated the long-term denudation rates of Serra do Mar to test this hypothesis. In this study, we measured the in situ-produced 10Be concentration in fluvial sediments to quantify the catchment-wide long-term denudation rates of the Serra do Mar escarpment in southern Brazil. We sampled the fluvial sediments from ten watersheds that drain both sides of the escarpment. The average long-term denudation rate of the oceanic side is between 2.1- and 2.6-fold higher than the rate of the continental side: 26.04 ± 1.88 mm ka-1 (integrating over between 15.8 ka-1 and 46.6 ka-1) and 11.10 ± 0.37 mm ka-1 (integrating over between 52.9 ka-1 and 85.4 ka-1), respectively. These rates indicate that the coastal base level is controlling the escarpment retreat toward the continental high lands, which is consistent with observations made at other high-elevation passive margins around the globe. The results also demonstrate the differential erosion along the Serra do Mar escarpment in southern Brazil during the Quaternary, where drainages over granites had lower average denudation rates in comparison with those over migmatites and gneisses. Moreover, the results demonstrate that the ocean-facing catchments have been eroded more intensely than those facing the continent. The results also reveal that drainage over the granites decreases the average denudation rates of the ocean-facing catchments and the 'sugarloaf' hills therefore are natural barriers that slowly retreat once they are exhumed. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

- We describe the geological, morphological, and climatic setting of the San Juan meteorite collection area in the Central Depression of the Atacama Desert (Chile). Our recovery activities yielded 48 meteorites corresponding to a minimum of 36 different falls within a 3.88 km2 area. The recovery density is in the range 9-12 falls km−2 depending on pairing, making it the densest among meteorite collection areas in hot deserts. This high meteorite concentration is linked to the long-standing hyperaridity of the area, the stability of the surface pebbles (> Ma), and very low erosion rates of surface pebbles (approximately 30 cm Ma−1 maximum). The San Juan meteorite population is characterized by old terrestrial ages that range from zero to beyond 40 ka, and limited weathering compared with other dense collection areas in hot desert. Chemical weathering in San Juan is slow and mainly controlled by the initial porosity of meteorites. As in the Antarctic and other hot deserts, there is an overabundance of H chondrites and a shortage of LL chondrites compared with the modern falls population, suggesting a recent (< few ka) change in the composition of the meteorite flux to Earth. [ABSTRACT FROM AUTHOR]

The present work quantifies the erosive processes in the two main substrates (schists-phyllites and granites-gneisses) of the upper Maracujá Basin in the Quadrilátero Ferrifero/MG, Brazil, a region of semi-humid tropical climate. Two measuring methods of concentration were used: (i) in situ produced 10Be in quartz veins (surface erosion rates) and (ii) 10Be in fluvial sediments (basin erosion rates). The results confirm that (i) erosion tends to be more aggressive close to the headwaters than in the lower parts of the basin and (ii) the region is now affected by dissection. [ABSTRACT FROM AUTHOR]

The Gurvan Bogd mountain range is a fault system characterized by strong earthquakes (M ∼ 8) separated by long periods of quiescence. Further to the previous works in the area, our study provides new data concerning the tectonic and climatic processes in the Gobi-Altay. To quantify the slip rates along the faults, we dated offset alluvial fans analysing thein situproduced10Be along profiles at depth. The slip rates along the Bogd strike–slip fault and its associated thrust faults over the Upper Pleistocene–Holocene period are 0.95 ± 0.29 mm yr−1 and comprised between 0.12 ± 0.02 and 0.13 ± 0.02 mm yr−1, respectively. The surfaces ages account for a cyclic formation of the fans over the past∼360 ka, in correlation with the terminations of the marine isotope stages 2, 6, 8 and 10.Terra Nova, 00, 1–8, 2005 [ABSTRACT FROM AUTHOR]

In eastern Indonesia, the Central Sulawesi fault system consists of complex left-lateral strike-slip fault zones located within the triple junction area between the Pacific, Indo-Australian and Eurasian plates. Seismicity in Central Sulawesi documents low-magnitude shallow earthquakes related, from NW to SE, to the NNW-trending Palu-Koro (PKF) and WNW-trending Matano fault zones. Study of the active fault traces indicates a northward growing complexity in the PKF segmentation. Left-lateral displacement of 370 ± 10 m of streams incised within fans, whose deposition has been dated at 11 000 ± 2300 years, yields a calculated PKF horizontal slip rate of 35 ± 8 mm yr-1 . This geologically determined long-term slip rate agrees with the far-field strike-slip rate of 32–45 mm yr-1 previously proposed from GPS measurements and confirms that the PKF is a fast slipping fault with a relatively low level of seismicity. [ABSTRACT FROM AUTHOR]