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Pheochromocytomas produce excess catecholamines that can result in intraoperative hemodynamic instability. Centers have reported variations in intraoperative hemodynamics with the retroperitoneoscopic versus the laparoscopic transperitoneal approach to adrenalectomies. When the retroperitoneoscopic approach was initiated for pheochromocytomas at our institution, the perception was of improved intraoperative hemodynamics, hypothesizing that increased retroperitoneoscopic insufflation pressures caused decreased venous return and less fluctuation in circulating catecholamines. The purpose of this study was to examine if a difference in intraoperative hemodynamics exists between a size-matched cohort of laparoscopic transperitoneal and retroperitoneoscopic pheochromocytoma patients.Unilateral adrenalectomies for pheochromocytoma performed via laparoscopic transperitoneal or retroperitoneoscopic approaches from 2015 to 2021 were identified from a surgical database. As larger tumors often underwent a laparoscopic transperitoneal approach, cases were matched 1:1 by tumor size. All patients received phenoxybenzamine. Groups were compared by patient characteristics, preoperative blockade, intraoperative hemodynamics and management, and early postoperative outcomes.There were 13 laparoscopic transperitoneal adrenalectomy cases matched to 13 retroperitoneoscopic cases according to tumor size. Both groups (laparoscopic transperitoneal and retroperitoneoscopic) were similar for age (53 years), body mass index (28.5 vs 29.7), sex (69% female), and side (8 vs 7 right). There was no difference in preoperative 24-hour urine metanephrines/normetanephrines (9.9/8.0 vs 2.4/5.7 μmol/day). The phenoxybenzamine dose was similar in both groups (112 vs 114 mg/24 hours), as were baseline heart rate, blood pressure, and mean arterial pressure. There was no difference in any intraoperative hemodynamic parameters or vasoactive interventions. Operative time, length of stay, and 30-day emergency visits were similar between groups.This matched cohort study did not find a difference in intraoperative hemodynamics between laparoscopic transperitoneal and retroperitoneoscopic adrenalectomy approaches for pheochromocytoma in appropriately selected and blocked patients.

We are very grateful to all the referees for their indispensable and unselfish work that greatly contributed to the improvement of the quality of the papers. The Department of the Environment and the Department of Science, Technology and University of the Aragón Government, as well as the Innovation Ministry of the Spanish Government (CGL2011-12465), provided financial support to organise the scientific meeting “Geomorphological Research in Spain” (Zaragoza, September, 2011). We thank the International Association of Geomorphologists (IAG), the Spanish Society of Geomorphology (SEG), and the Spanish Society of Quaternary Studies (AEQUA) for supporting the initiative. We are also very grateful to Dr. Cinta Marín for helping with the preparation of the bibliometric data and supplementary material presented in this guest editorial.

Fluvial systems in uplifting terrain respond to tectonic, climatic, eustatic and local base-level controls modified by specific local factors, such as river capture. The Rio Alias in southeast Spain is an ephemeral, transverse-to-structure fluvial system. The river drains two interconnected Neogene sedimentary basins, the Sorbas and Almeria basins, and crosses two major geological structures, the Sierras de Alhamilla/Cabrera and the Carboneras Fault Zone. Regional epeirogenic uplift resulted in sustained fluvial incision during the Quaternary, punctuated by major climatically driven periods of aggradation and dissection, which created a suite of five river terraces. The river terrace sequence was radically modified in the late Pleistocene by a major river capture (itself a response to regional tectonics), localized tectonic activity and eustatic base-level change. The Rio Alias is defined by four reaches; within each the climatically-generated, region-wide, fluvial response was modified by tectonics, base-level change or river capture to varying degrees. In the upper part of the basin (Lucainena reach), climate was the dominant control on river development, with limited modification of the sequence by uplift of the Sierra Alhamilla and local drainage reorganization by a local river capture. Downstream of the Sierra Alhamilla in the Polopus reach, the climatic signal is dominant, but its expression is radically modified by the response to a major river capture whereby the Alias system lost up to 70% of its pre-capture drainage area. In the reach adjacent to the Carboneras Fault Zone (Argamason reach), modification of the terrace sequence by local tectonic activity and a resultant local base-level fall led to a major local incisional event (propagating c. 3–4 km upstream from the area of tectonic disturbance). At the seaward end of the system (El Saltador reach) Quaternary sea-level changes modified the patterns of erosion and incision and have resulted in steep incisional terrace profiles. The signals generated by regional tectonics and the Quaternary climate change can be identified throughout the basin but those generated by ongoing local tectonics, river capture and sea-level change are spatially restricted and define the four reaches. The connectivity of the system from the headwaters to the coast decreased through time as incision progressed, resulting in changes in local coupling characteristics. Copyright © 2012 John Wiley & Sons, Ltd.

Alluvial fans and debris cones link two zones of the fluvial system (e.g. hillslope gully systems to stream channels; mountain catchment sediment source areas to main river systems or to sedimentary basins) and therefore have important coupling or buffering roles. These roles may be both functional and preservational. The functional role includes debris-cone coupling, which controls sediment supply from hillslope gully systems to stream channels, influencing channel morphology. Coupling through larger alluvial fans, expressed by fanhead trenching, causes a distal shift in sedimentation zones, or when expressed by through-fan trenching, causes complete sediment by-pass. The preservational role stems from the fact that fans and cones are temporary sediment storage zones, and may preserve a record of source–area environmental change more sensitively than would sediments preserved further downsystem. Fan coupling mechanisms include distally-induced coupling (basal scour, ‘toe cutting’, marginal incision) and proximally-induced coupling (fanhead and midfan trenching). These mechanisms lead initially to partial coupling, either extending the immediate sediment source area to the stream system or shifting the focus of sedimentation distally. Complete coupling involves transmission of sediment from the feeder catchment through the fan environment into the downstream drainage or a sedimentary basin. The implications of coupling relate to downstream channel response, fan morphology, sedimentation patterns and vertical sedimentary sequences. Temporal and spatial scales of coupling are related, and with increasing scales the dominant controls shift from storm events to land cover to climatic and base-level change and ultimately to the relationships between tectonics and accommodation space. Finally, future research challenges are identified. Modern dating techniques and sophisticated analysis of remotely sensed data can greatly improve our understanding of fan dynamics, and should lead to better cross-scale integration between short-term process-based approaches and long-term sedimentological applications, while maintaining high quality field-based observations. Copyright © 2011 John Wiley & Sons, Ltd.

Lake sediment and geomorphic evidence from the Loch of the Lowes/St Mary's Loch basin in the central Southern Uplands of Scotland provide a multiproxy reconstruction of changing sediment availability and transmission through the catchment. Interrogation of magnetic, geochemical and grain size parameters for lake and catchment materials suggests it is possible to identify independent proxies that reflect both supply (availability) and discharge (capacity) controls on the sediment signal. Chronological control for the lake sediment record is proposed by linking a210Pb/137Cs chronology for the last c. 120 yr to an age/depth profile based on proposed temporal correlations between cyclic HIRM/χLF variability and the North Atlantic Oscillation. Geochronological studies on debris cones and alluvial fans yield evidence for episodic hillslope gullying ~2000—0 BC with more extensive region-wide slope instability AD 700—900, 1100—1300 and after AD 1450—1550 and gully stabilization over the last 150 years. The latter two episodes coincide with the lake sediment evidence for increased sediment supply from ~AD 1600 declining after ~AD 1870. The capacity-related lake proxies appear to identify phases of increased flooding ~AD 1625—1650, 1680—1700, 1730—1760, 1800—1815, 1850—1880, 1910—1930, 1960—1970 and possibly the 1990s. Close correspondence between the sediment `flood' archive and historical records of flooding in Scotland suggests that lake-catchment systems of this type have the potential to yield valuable information on past hydrological response.

The Rio Alias of southeast Spain crosses a major tectonically active structure, the Carboneras Fault Zone, within the central portion of the drainage basin. The fault originated in the mid-Miocene and has c.40 km of strike-slip offset. The impact of late Quaternary movement along the fault zone on the evolution of the Rio Alias is addressed. Geomorphological and sedimentological analysis of the landform assemblage preserved suggests the development of highly sinuous meander loops and laterally incising streams during phases of tectonic activity. Continued tectonic activity led to the abandonment of the meander loops and a wave of incision that propagated c.2 km upstream. The propagation of this incision wave was restricted by the development of a nickpoint, itself controlled by an anticlinal structure sub-parallel to the fault zone. Syn-sedimentary and post-depositional faulting is evident within the late Quaternary fluvial sediments and suggests dominantly vertical movement along the fault lines with downthrow to the southeast. Regional climatic patterns of aggradation and incision resulting in a basinwide terrace sequence were complicated (i.e. an additional terrace was created and meander wavelength was changed) through the study reach by tectonic activity. This study highlights the importance of tectonically modified sequences when interpreting climatically generated sequences of aggradation and incision.

The tributary junctions to main rivers within incised canyons reflect the relationships between stream power and sediment fed to the main river by tributary. Tributary junctions within the Three-Gorges valley of the Yangtze River, China, were classified into 7 types on the basis of the presence or absence of tributary-junction fans, and the size and style of the fans. Three reaches, totaling 180 km in length, were mapped in the field, and for a sample of 120 tributary junctions, morphometric properties of the feeder catchments were derived. Small steep tributaries do not generate tributary-junction fans, nor do the largest tributaries. For intermediate-sized tributary catchments (of approximately 1–30 km2) threshold conditions can be identified between the relatively steep, more deeply dissected catchments (mean basin slope > approximately 0.1; relief range approximately 250–800 m) that generate large tributary-junction fans, and less steep, less deeply dissected catchments (mean basin slope

New data from Chapel Beck in the southwest Howgill Fells combined with existing data support the identification of three phases of extensive hillslope gullying after 2200, between 1250–700 and after 500 cal. BP. Examination of cumulative probability density function (CPDF) plots of the distribution of calibrated radiocarbon dates confirms the identification of these phases. There are differences in the spatial distribution of geomorphic activity between these phases; with the c. 2200–1800 cal. BP episode limited to the western Howgill Fells. In comparison, the 1250–700 and post-500 cal. BP episodes are more widespread cross-region phenomena, and affected the more remote central fells. Pollen and geochemical data reveal several phases of increased human activity in these uplands, with small-scale temporary clearances during the late Bronze Age / early Iron Age and more substantial clearances during the late Iron Age and Romano-British times (2300–1500 cal. BP), and these were followed by woodland expansion and decline in human activity during both the mid- to late Iron Age and the period after the Roman withdrawal from Britain (after 1500 cal. BP). The final substantial woodland clearances occurred from c. 1100–900 cal. BP, after which there has been little woodland recovery. A range of pollen sites across the Howgill Fells indicate that there is spatial variability in the level of human activity and impact. Iron Age / Romano-British woodland clearances appear to have affected the west of the region more than the remote central valleys, whereas the later 1100–900 cal. BP woodland reduction affected the entire region. This pattern is similar to that identified from the geomorphology, and demonstrates the importance of pollen sites that record local palaeo-vegetation information and the significance of using a series of sites to explore intra-regional variability in the vegetation history. We suggest that human activity is a critical factor in mediating the late Holocene geomorphic record, but climate and particularly individual storms are the trigger mechanism responsible for erosion and incision on hillslopes and within the wider fluvial system. Palaeoclimate data (humification and plant macrofossil) from peat deposits at Archer Moss identify shifts to wetter conditions: c. 3100–2700; 2400–1700; 1300–1100; and after 650 cal. BP, and probably reflect increases in summer wetness. Of these, the 2400–1700, 1300–1100 and post-650 cal. BP wetter phases coincide with increased geomorphic activity, and perhaps encouraged incision on hillslopes rendered more susceptible to erosion by the activities of people.

Dryland alluvial fans developed along the northern flanks of the Sierra Lisbona in the north-western Vera basin (Almeria region, southeast Spain) display negligible amounts of incision despite distal base-level lowering of > 30 m by the modern drainage network. The fans are of early-middle Quaternary age and are graded to a coeval river terrace, now isolated from the modern drainage network. The negligible incision is due to the encasement and ‘fossilisation’ of the alluvial fans by calcrete. This paper explores the reasons for such fossilisation and assesses the relative importance of pedogenic and groundwater mechanisms for calcrete formation within an alluvial fan setting. A single fan was selected for detailed examination. The geomorphological and sedimentological features of the fan, its catchment area and their relationship to the distal river terrace were documented. Qualitative and semi-quantitative petrographic and scanning electron microscope analyses of calcrete samples collected from transects across the fan surface, and within its distal top river terrace surface, enabled the style, pattern and relative timing of calcrete development to be assessed. Calcrete fabrics comprised initial micritic grain-coating cements, pellets and glaebular carbonate nodules, with interstitial spaces infilled by equant sparite and microsparite mosaics. It is proposed that the early phases of calcrete development were dominated by pedogenic processes with increasing groundwater calcretisation over time. Point count data indicated increased quantities of interstitial sparite and microsparite cement within near-surface proximal fan calcretes and at depth across the fan, suggesting that groundwater processes played a more important role in calcrete formation in these locations. The contribution of groundwater to calcrete development can be best explained by the intrinsic funnelling of groundwater from the catchment through the proximal fan head area, a zone where the fan gravels are thinnest. Calcrete ‘fossilisation’ appears to have followed a reduction in the fan catchment area as a result of rockfalls and watershed stream capture, which reduced water and sediment supply to the fan and enabled surface stabilization and calcrete development to take place. The reduced sediment/water supply, combined with calcrete fossilisation, appears to have protected the alluvial fans from regional base-level lowering. The implications of these results for existing pedostratigraphic models of calcrete development in alluvial fans are subsequently explored.

A 100-year storm that occurred in 1982 caused major geomorphic changes in the main valleys of the northern Howgill Fells, northwest England. Those changes, which were documented at that time, involved extensive hillslope gully erosion, alluvial fan sedimentation, and substantial sediment input to the stream systems. The streams channels, which had hitherto been dominantly single-thread, relatively stable channels, responded in many reaches by switching to wide shallow unstable locally braided channels. Over the 20 years since the event there has been a partial recovery to channel geometries similar to the pre-flood conditions, however the degree of recovery contrasts between two neighbouring valleys, Bowderdale and Langdale. The channel of Bowderdale Beck has largely recovered. Flood sedimentation zones have largely stabilised and new single-thread channels have cut through most of the former braided reaches. In some places channel widths remain higher than the pre-flood values, and locally recovery has been modified by a lagged complex response. In Langdale, recovery is only partial with many reaches demonstrating sustained instability over the 20-year post-flood period. Furthermore, the overall spatial patterns suggest some reach-to-reach transfer of coarse sediment, shifting zones of instability downstream. The contrasts between the two valleys appear to relate to different hillslope-to-channel coupling characteristics, themselves inherited from late Pleistocene conditions. These contrasts are also evident in the longer-term (post-1949) history of channel change and stability in these two streams, indicative of the higher intrinsic instability of the Langdale system.

In the Solway Firth — Morecambe Bay region of Great Britain there is evidence for heightened hillslope instability during the late Holocene (after 3000 cal. BP). Little or no hillslope geomorphic activity has been identified occurring during the early Holocene, but there is abundant evidence for late Holocene hillslope erosion (gullying) and associated alluvial fan and valley floor deposition. Interpretation of the regional radiocarbon chronology available from organic matter buried beneath alluvial fan units suggests much of this geomorphic activity can be attributed to four phases of more extensive gullying identified after 2500–2200, 1300–1000, 1000–800 and 500 cal. BP. Both climate and human impact models can be evoked to explain the crossing of geomorphic thresholds: and palaeoecological data on climatic change (bog surface wetness) and human impact (pollen), together with archaeological and documentary evidence of landscape history, provide a context for addressing the causes of late Holocene geomorphic instability. High magnitude storm events are the primary agent responsible for gully incision, but neither such events nor cooler/wetter climatic episodes appear to have produced gully systems in the region before 3000 cal. BP. Increased gullying after 2500–2200 cal. BP coincides with population expansion during Iron Age and Romano-British times. The widespread and extensive gullying after 1300–1000 cal. BP and after 1000–800 cal. BP coincides with periods of population expansion and a growing rural economy identified during Norse times, 9–10th centuries AD, and during the Medieval Period, 12–13th centuries AD. These periods were separated by a downturn associated with the ‘harrying of the north’ AD 1069 to 1070. The gullying episode after 500 cal. BP also coincides with increased anthropogenic pressure on the uplands, with population growth and agricultural expansion after AD 1500 following 150 years of malaise caused by livestock and human (the Black Death) plagues, poor harvests and conflicts on the Scottish/English border. The increased susceptibility to erosion of gullies is a response to increased anthropogenic pressure on upland hillslopes during the late Holocene, and the role of this pressure appears crucial in priming hillslopes before subsequent major storm events. In particular, the cycles of expansion and contraction in both population and agriculture appear to have affected the susceptibility of the upland landscape to erosion, and the hillslope gullying record in the region, therefore, contributes to understanding of the timing and spatial pattern of human exploitation of the upland landscape.

The Rio Alias is a transverse river system developed within the Sorbas and Almeria Neogene sedimentary basins within the Internal Zone of the Betic Cordillera, southeast Spain. Headwaters of the Rio Alias rise in the southern margins of the Sorbas basin following a superimposed transverse course across the Sierra Alhamilla/Cabrera and its associated boundary faults. A major river capture event within the Sorbas Basin (c.70 ka) created a situation whereby the Rio Alias abruptly lost c. 70% of its drainage area. Such an extensive loss of drainage area led to significant modification of the fluvial system in both upstream and downstream zones on the capturing stream, and downstream on the beheaded system. On the beheaded Rio Alias, a combination of terrace mapping, clast identification/analysis, field descriptions of pedological development and mineral magnetic analysis allows the relative timing of the capture event to be confirmed. Examination of the fluvial architecture of the Quaternary terrace deposits reveals significant changes in bedform geometry, involving a reduction in bedform height, degree of channelisation and maximum clast size in the post-capture sediment assemblage. The post-capture evolution of the Rio Alias has been heavily influenced by the river capture event, highlighting the need for further analysis of beheaded drainage systems and their influence on developing landform assemblages.

The gravel plain of the northern UAE is bounded to the east by the Musandam Mountains and to the west by the northernmost extension of the dunes of the Rub Al-Khali. Further west, beyond the dunes lies the coast of the Arabian gulf. The gravel plain comprises coalescent Quaternary alluvial fans, supplied with sediment from catchments in the Musandam Mountains. The boundary between the plain and the dunes follows the outline of the fans, and its width varies in relation to the size of the drainage basins supplying sediment to the fans. Linear dune ridges appear to wrap around the outline of the margins of the major fans. This suggests that the two landform assemblages are related. Where one wadi system crosses the dunefield the field relationships further suggest some contemporaniety of development. Where the mountain front is drained by catchments too small to sustain fan deposition, the dunes advance to the mountain front. Correlations with other work suggest that there were major phases of both fan sedimentation and dune accumulation during the late Pleistocene. Cooler and/or wetter climatic conditions enhanced sediment supply to the alluvial fans. Strong northwesterly winds and greater sediment availability from the then dry floor of the Arabian Gulf may have been responsible for dune accumulation. Later dune reworking may reflect Holocene aridity.

Mineral magnetic and soil iron oxide data are applied to questions of relative age correlation of alluvial fans and lake sediments in the Tabernas basin, southeast Spain, within a context of interaction between tectonics and climatic change. Within the Tabernas basin, the sediment sequences and morphological evolution of late Quaternary alluvial fans suggest climatic change as the primary control. The fans toe out at the upper margins of a former lake, created in response to tectonic uplift. Magnetic and iron oxide data from soils, particularly dithionite-extractable iron (Fe d ), and frequency-dependent magnetic susceptibility ( χ FD %) accord with the relative age relationships suggested by more conventional field-based geomorphic observations. Magnetic data from the lake sediments suggest the main provenance characteristics of the sediments, but also reveal a shift in sediment sources towards the end of the lake period (probably during the late Pleistocene) to sediment supplied from a more active fluvial system from soil erosion within the Sierra de los Filabres part of the catchment. Hence, although the locations of the fans and the existence of the lake relate primarily to tectonics, the fan sequences themselves appear to be primarily climatically controlled, and there is evidence of a climatic influence over the source of sediment input into the lake during the late Pleistocene.

Tectonics, climate and base level are the underlying controls of alluvial fan development. On many fans base level is stable, but where base-level change occurs it may itself be a response to tectonics or climatic change. Tectonically induced base-level change will be temporally independent of climatic change, and will show spatial variability depending on the rate of propagation of tectonically induced regional dissection. This is illustrated by the Tabernas fans, southeast Spain. The timing of climatically induced base-level change follows the timing of climatic change itself, and will show more consistency of spatial relationships within groups of fans affected. Alluvial fans which toe out in coastal zones or at lake shorelines may be influenced by climatically controlled base-level changes. Conventionally, a fall in base level would be expected to cause dissection of the distal fan zone. However, the reverse may occur, with fan progradation taking place in response to a base-level fall, and dissection occurring in response to a base-level rise. Two contrasted case studies are considered, based in part on previously published work, from dry-region alluvial fan zones, the coastal Cabo de Gata fans in southeast Spain and the Stillwater and Cold Springs fans in Nevada, USA. In these areas, base-level changes occurred in response to late Quaternary eustatic changes of sea level, and changes in the levels of pluvial lakes, respectively. Within both areas there are fans not affected by base-level change (Cabo de Gata, west-coast and inland fans; Cold Springs fans), and others where base-level change has been important in fan evolution (Cabo de Gata, east-coast fans; Stillwater fans). The differences in geomorphic regime between those fans influenced by base-level changes and those not are expressed in morphometric contrasts and different fan profile and plan characteristics. Within those fans influenced by base-level changes, the different mechanisms have influenced the location and elevation of the zone of incision. The differences can be attributed in part to the temporal interactions of base-level change with climatically induced changes in sediment supply, and in part to differences in gradients of the foreshore exposed by the falling sea or lake base levels.

This paper presents a review of the coupling concept in fluvial geomorphology, based mainly on previously published work. Coupling mechanisms link the components of the fluvial system, controlling sediment transport down the system and the propagation of the effects of base-level change up the system. They can be viewed at several scales: at the local scale involving within-hillslope coupling, hillslope-to-channel coupling, and within-channels, tributary junction and reach-to-reach coupling. At larger scales, coupling can be considered as zonal coupling, between major zones of the system or as regional coupling, relating to complete drainage basins. These trends are illustrated particularly by the examples of hillslope-to-channel coupling in the Howgill Fells, northwest England, badland systems in southeast Spain, alluvial fans in Spain, USA and UAE, and base-level-induced dissection of Neogene sedimentary basins in southeast Spain. As the spatial scales increase, so do the timescales involved. Effective temporal scales relate to magnitude and frequency characteristics, recovery time and propagation time, the relative importance changing with the spatial scale. For downsystem coupling at the local scale, the first two are important, with propagation time increasing in importance in larger systems, especially in those involving upsystem coupling related to base-level change. The effective timescales range from the individual event, with a return period of decades, through decadal to century timescales for downsystem coupling, to tens to hundreds of thousands of years for the basinwide response to base-level change. The effective timescales influence the relative importance of factors controlling landform development.

Primary hyperaldosteronism is an important and commonly unrecognized secondary cause of hypertension. This article provides an overview of the current literature with respect to screening, diagnosis, and lateralization. Selection and outcomes of medical and surgical treatment are discussed.

The evolution of an incising drainage network controls regional geomorphic development, but is in turn controlled by four sets of dynamic factors. These are as follows: tectonics, including both regional epeirogenic uplift and more local tectonic deformation; climatic change, affecting variations in flood power and sediment supply; base level; and local factors such as river capture, related to the development of the drainage network itself. The geomorphology of four uplifted Neogene sedimentary basins in the eastern Betic Cordillera of Almeria, Spain, demonstrates how these factors interact and operate over a range of temporal and spatial scales. The basins were marine basins until the early Pliocene, when differential epeirogenic uplift caused emergence and the initiation of the drainage networks; first in the Tabernas, then in the Sorbas, and finally in the Vera and Almeria basins. The last two became terrestrial in the early Pleistocene. The modern landscape reflects the influence of differential regional uplift rates on the long-term dissectional history, operating regionally over the whole period of landform development. The extremes are represented on the one hand by the deeply dissected Tabernas basin and on the other hand by the centre of the Almeria basin, which is dominated by coalescent aggrading alluvial fans. The Quaternary climatic signal is another regional signal, expressed by the sediment-led terrace sequence, with aggradation occurring primarily during Pleistocene global glacials and incision during the interglacials. These regional signals are modified locally by the other factors. Local neotectonic deformation is particularly important in the Tabernas and Almeria basins. Base-level change induced by tectonic activity and by river capture is important locally throughout the area, but the effects of base-level change induced by Quaternary sea-level change are restricted to the coastal zone. River capture has had profound effects, modifying the drainage areas. The Vera basin has gained drainage area substantially, whereas that of the Almeria basin has decreased. The most important effects have been on base level and incision rates, especially in the Sorbas basin. The overriding long-term control on drainage development and therefore on landform dynamics has been the pattern of regional epeirogenic uplift, onto which the Quaternary climatically controlled aggradation/dissection sequence has been imposed. These are regional signals that have been modified locally by the more spatially and temporally restricted signals generated by base-level change and river capture.

The complex badland landscape at Tabernas results from a combination of relief amplitude generated by tectonic uplift since the Pliocene and reactivated several times during the Pleistocene, the properties of the Tortonian sedimentary rocks and a predominantly arid climate. The landscape is dominated by deep incision of the main river systems, which continues in part of the headwater tributaries, and characterized by contrasting slope morphologies and a variety of microecosystems. The Tabernas badlands exhibit a diversity of landforms resulting from the combination of multi-age soil surface components that allow a variety of processes to operate at different rates. These are dominated by rilling and shallow mass movements on south-facing hillslopes. On old surfaces and north-facing hillslopes, where biological components are present, overland flow with variable infiltration capacity and low erosion rates prevail. Incision in the gully bottoms occurs in the most active areas.

The Late Glacial and Holocene geomorphology of the Manx uplands has received scant attention in previous researches. Solifluction deposits and terraces provide the earliest evidence for geomorphic activity after deglaciation. Fluvial incision into drift-choked valleys is correlated with the formation of the large mountain front alluvial fans that flank the Manx uplands. Formation of these alluvial fans is constrained to 15,000–10,500 cal. years BP by 14 C dates on organic deposits beneath and above the alluvial fan gravels. Alluvial fan and river terraces along four valleys postdate this incision. Optically Stimulated Luminescence (OSL) and 14 C dating provide a tentative chronology for these landforms. The higher terraces are Late Glacial fluvial surfaces that were probably occupied by rivers into the Holocene. Incision during the Late Holocene led to the abandonment of the higher surfaces, producing a suite of younger river terraces and alluvial fan surfaces. Independent dating constrains this fluvial activity to post-Bronze Age (3500–2800 cal. years BP). Increased human activity and climatic change during the Late Holocene are possible causes for this increased geomorphic activity.

The sensitivity of upland fluvial systems depends on the magnitude and frequency of sediment and flood producing events, modified by the internal coupling characteristics of the system. This paper assesses the role of hillslope/channel coupling for the sensitivity of upland geomorphic systems, using evidence from a 30-year monitoring programme of geomorphic change in the Carlingill valley, Howgill Fells, northwest England. In the hillslope zone, there is little sediment supply to the stream system. Locally, slope failures occur in response to extreme events (six such events in 30 years within the ca. 6 km 2 Carlingill valley). In the footslope coupling zone, basally induced gullies are major sediment sources to the stream. Sediment-production events occur ca. 30 times per year, feeding sediment to basal debris cones. Stream floods which can entrain these sediments occur once every ca. 2–5 years. Stream channel morphology is adjusted to this regime. Downstream of gullies, channels are wide and braided; elsewhere they are narrow and single-thread. As the gullies develop, however, this coupling weakens and the eroding slopes eventually stabilise by revegetation. Over the 30-year monitoring period, there has been a progressive trend towards gully stabilisation, and an associated reduction in channel instability. Massive destabilisation may occur in response to rare extreme flood events. Such an event (return period >100 years) occurred in neighbouring Langdale and Bowderdale valleys in June 1982. That event destabilised the system, causing slope failures, fan deposition, and in some places, a switch in channel style to wide braided channels. Since 1982 there has been a progressive recovery by slope stabilisation and single-thread sinuous channels have become reestablished. A different style of extreme event occurred in Carlingill in October 1998, in response to the wettest week in the 30-year period. A slope failure fed debris flows 400 m downslope, almost coupling with the channel system. Future climatic change could render the system prone to destabilisation, through either extreme flood events or through major slope failures.

In mountain areas affected by uplift, significant reorganization of drainage networks can occur through river capture. This modification can dramatically affect sediment flux and routing into adjacent sedimentary basins. It is thus important to obtain information on rates and direction of changes in catchment areas in such environments. This can be achieved where the original, precapture catchments can be compared with the postcapture scenario. This paper examines three modern mountain catchments from southeast Spain that were affected by river capture, and that fed relict Pliocene–Pleistocene alluvial fan systems. Morphometric data have been collated for complete Quaternary mountain catchment piedmont fan systems. These data are used to establish regressions to determine catchment area and basin relief from a combination of fan characteristics (area and gradient). These relationships are then used to predict the original catchment characteristics for the three Pliocene–Pleistocene relict fans and compared with the modern catchments to quantify the magnitude and direction of changes, which have affected the drainage basins since fan abandonment in the early Pleistocene. The figures suggest that the catchment areas are responding to regional uplift, most significantly by drainage net expansion facilitated by river capture rather than lowering of surface relief. As a result, sediment routing into the sedimentary basins has been radically altered.

In arid mountain areas, the dating and correlation of alluvial depositional surfaces is often uncertain. Especially in regions where the geomorphology is not well known, surface modification by the development of soil and desert pavement may allow the correlation of geomorphic surfaces and estimation of at least their relative ages. Pleistocene wadi terraces and associated alluvial fans occur in Wadi Al-Bih, U.A.E. and Oman, for which correlations and age relationships are not known. Three age-related groups of fans and terraces have been identified and mapped on the basis of their morphostratigraphic relationships. Deposition of the oldest terrace sediments and associated fans followed a long period of sustained incision after Miocene uplift of the region. The younger two groups of terraces and fans are inset within the older group. To identify the gross effects of pavement development, comparisons have been made between terrace surface and subsurface particle-size distributions. The older terraces have finer surface sediments and a greater contrast between finer surface and subsurface sediments than the younger terraces. This reflects the degree of pavement development. Particle size on the fan surfaces is comparable with that on the equivalent terrace surfaces. Criteria for the classification of pavements were developed based on clast fracturing and angularity, size, sorting, packing, and surface texture, from which a simple index of pavement development has been derived. Other properties, rock varnish and weathering characteristics, were also recorded; but these proved to be less discriminatory than pavement characteristics. The pavement data have been augmented by observations on soils. Detailed studies of pavements on terraces (8 sites, 12 samples covering the three age groups) and fans (5 sites, 10 samples covering the three age groups) allow differentiation between age-groups. The three terraces show three different age-related pavement types, expressed by differences in the pavement development index. Weakly-developed pavements (little fracturing, sub-rounded clasts, some modification of the depositional fabric, incipient soil development, stage I CaCO3 accumulation) occur on the youngest terrace and fan surfaces. Moderately-developed pavements (clast fracturing, sub-angular clasts, moderate sorting and packing, deeper soil development, stage II CaCO3 accumulation) occur on the middle terrace and fan surfaces. Well-developed pavements (complete clast fracturing into small angular fragments, mature sorting and packing of the pavement surface, deep soil development with strong horizonation, stage III CaCO3 accumulation) occur on the highest terrace and oldest fan surfaces. There are minor differences between the youngest pavements on terraces and fans, which reflect initial sedimentological differences. These differences become less as the pavements develop. On the basis of comparative studies, the oldest terrace is estimated to date from sometime prior to ca. 100 ka BP, the second terrace and the most extensive fan surface from the Late Pleistocene, and the youngest terrace and fan phase from the Latest Pleistocene or Early Holocene.

Dated shorelines of late Pleistocene pluvial Lakes Lahontan (Great Basin Desert, northwest Nevada) and Mojave (Mojave Desert, eastern California) provide timelines for the assessment of alluvial fan sedimentation at the lake margins during the late Pleistocene to early Holocene. Two sets of alluvial fan systems have been mapped: the Stillwater fans, feeding Lake Lahontan; and the Zzyzx fans, feeding Lake Mojave. Their contrasting morphologies suggest different responses of the two fan systems to late Pleistocene to early Holocene climatic change. At the time the Stillwater fan systems underwent minimal sedimentation, with the catchment hillslopes apparently stable. The Zzyzx fans experienced major changes in water and sediment supply from the catchment hillslopes. There was a major phase of hillslope debris-flow activity, followed by fanhead trenching and distal fan progradation. Both areas were wetter and colder in the late Pleistocene than they are today, but during the transition to the Holocene the Zzyzx area was more likely to experience intense rains associated with the monsoonal penetration of warm moist tropical air into the Southwest. Vegetation reconstructions for the late Pleistocene to the early Holocene suggest that catchment hillslopes in the Mojave supported a desert shrub vegetation, but those in the Stillwaters supported juniper woodland and grasses at low elevations and pine at higher elevations. Contrasts in hillslope vegetation cover together with storm activity may account for the different responses of the alluvial fans to climatic change during the Pleistocene to Holocene climatic transition. After the falls in lake levels of Lakes Lahontan and Mojave in the early Holocene, both areas underwent aridification, resulting in reductions in hillslope vegetation cover. Increased storm runoff led to fanhead trenching and distal progradation of the alluvial fans. Variations in fan style at that time may relate primarily to base-level conditions resulting from different gradients on the exposed lake shores.

Conventionally, a fall in base level is seen as stimulating incision into the distal zones of alluvial fans. In the Cabo de Gata ranges of southeast Spain evidence exists to the contrary. Two sets of Quaternary coastal alluvial fans demonstrate the interaction between climatically-driven variations in the supply of sediment and eustatically-driven changes in base level. The fans are supplied from Miocene volcanic terrain within which no evidence can be found for major tectonic deformation during the period of fan development. The evolution of the east-coast fans has been affected by variations in sediment supply and changes in sea level. The west-coast fans were buffered from the effects of changes in sea level by coastal barriers. Three phases of past sedimentation can be identified on the fans. These can be differentiated on the basis of field observations of soil profiles (particularly colour of the B horizons and accumulation of CaCO3), and laboratory analyses of sequential iron oxide extractions and magnetic mineral properties. The two earlier (major) sedimentation phases were coincident with global glacials (>ca. 135 ka and ca.85-10 ka, based on the stratigraphy and uranium/thorium dating of the coastal sediments). High sea levels during the intervening interglacial and during the Holocene caused erosion of the distal zones of the east-coast fans which led to channel incision into the fan surfaces. On the west-coast fans no such incision occurred, simply proximal incision by small fanhead trenches. The youngest (relatively minor) phase of fan sedimentation has occurred during the Holocene. These contrasting contexts have produced differing styles of fans, with telescopic fan morphology on the east-coast and stacked morphology on the west-coast fans. The differences are reflected in the fan profiles, with steeper gradients dominating the east-coast fans, and extensive lower gradient distal surfaces on the west-coast fans. Fan morphometry, based on analysis of the residuals from drainage area to fan area and gradient regressions, also differentiates between the fan contexts. The fan building phases appear to be controlled proximally by climatically-driven pulses of sediment supplied to the fans. These occurred during global glacials coincident with low sea levels, and caused fan progradation onto the exposed foreshore. The intervening global interglacials were times of little fan sedimentation, and on the east coast, where high sea levels were able to erode the fan toes, deep through-fan dissection ensued., This research has been partially supported by the British Council/Spanish Government—Acciones Integradas Programme. Diane Spivey helped with some of the field surveying. John Dearing gave help in the interpretation of the mineral magnetic data. We also thank the staff of the Graphics section of the Department of Geography, University of Liverpool for producing most of the illustrations.

Hillslope gullies, cut in glacial till, supply sediment to the channel of Carlingill, a small upland stream in the Howgill Fells, northwest England. Coupling between the two zones is fundamental to the dynamics of the whole system. Gully development is initiated by stream erosion at the slope base, and maintained by the periodic removal of the eroded sediment by stream floods. As gully development proceeds the strength of coupling between gully and stream channel decreases, and is ultimately broken, leading to the stabilisation of the gullied slopes by revegetation. The coarse sediment supplied by the gullies becomes the stream bedload controlling the stream dynamics. The channels in zones away from gully sediment sources tend to be narrow, single-thread, relatively stable channels. Those downstream of gully sites tend to be wide, often braiding and unstable. Monitoring of sediment movement between gullies and stream channels, at two spatial scales, over temporal scales of 6 and 25 years, has identified a decrease in coupling with progressive gully development, causing a decrease in the frequency of sediment supply events and an increase in the complexity of sediment storage within the system. Over the longer term, two phases of gully development can be identified. Large gullies developed in the late Holocene, probably ca 1 000 yrs BP, which overloaded the system, causing deposition of large debris cones and alluvial fans. More recently, over the last ca 200 years, smaller gullies developed and locally stabilised. Their transient influence on channel morphology has been identified through the application of lichenometry to the valley floor morphology. Coupling relationships are fundamental to the geomorphology of slope and channel systems in this environment, over a range of timescales., Résumé Des ravins entaillent des versants, façonnés dans une couverture morainique et déversent des sédiments dans le lit du Carlingill, petit torrent des Howgill Fells, au Nord Ouest de l'Angleterre. La définition des liens de couplage qui existent entre ces deux éléments du système est fondamentale pour comprendre la dynamique du système dans son ensemble. La formation des ravins est liée à l'érosion de la base du versant par le torrent; ils se maintiennent grâce au travail de curage des crues qui emportent périodiquement les sédiments qu'ils y ont apportés. Cependant, au cours de l'évolution des ravins, l'importance des liens qui les relient au torrent se relâche pour finalement disparaître, ce qui conduit à leur stabilisation par revégétalisation de leurs pentes. Les sédiments grossiers fournis par les ravins deviennent la charge de fond du torrent et un élément fondamental de sa dynamique. Les lits fluviaux hors des zones ravinées ont tendance à être étroits, à chenal unique et relativement stables. Ceux situés en aval des versants ravinés sont larges, instables, et souvent disposés en tresses. L'étude des transports de sédiments entre les ravins et les lits des torrents, à deux échelles spatiales, et plusieurs échelles de temps (périodes de 6 et 25 ans) met en évidence l'affaiblissement du rapport entre ces transports et la progression du ravinement; ceci provoque une décroissance de la fréquence des événements producteurs de sédiments et une augmentation de la complexité des relais des stocks sédimentaires dans le système. Sur le long terme, nous avons pu mettre en évidence deux phases de ravinement. De grands ravins se sont développés pendant l'Holocène récent, probablement autour de 1 000 BP. Ils ont fourni au système d'énormes surcharges sédimentaires, déposées sous forme de grands cônes de débris et cônes torrentiels. Plus récemment, depuis 200 ans environ, de plus petites ravins se sont développés puis localement stabilisés. Leur influence temporaire sur la morphologie des lits fluviaux a été mise en évidence par des études de lichénométrie appliquées à l'analyse de la morphologie du fond des vallées. Le couplage " ravins-lits fluviaux" est fondamental pour expliquer la géomorphologie des pentes et des lits fluviaux dans ces milieux, à plusieurs échelles de temps., Harvey Adrian M. Coupling between hillslope gully systems and stream channels in the Howgill Fells, northwest England: temporal implications/Le couplage des systèmes de ravins et des lits fluviaux dans les Howgill Fells, nord-ouest de l'Angleterre : signification temporelle. In: Géomorphologie : relief, processus, environnement, Mars 1997, vol. 3, n°1. pp. 3-19.

Four areas were selected to represent a range of processes characteristic of badland surfaces in southeast Spain: Petrer and Monnegre in Alicante, Vera and Tabernas in Almeria. At Petrer, rilling and swelling processes produce a deeply cracked surface drained by a finely textured network of shallow rills. At Monnegre, piping and rilling are differentially developed on slopes ultimately controlled by basal incision. At Vera, aspect-controlled lichen and vegetation cover produce a sequence of badland development within which the relative importance of piping, mass movement and rilling varies through the sequence. At Tabernas, simple overland flow is the dominant process, but aspect influences rill network density and badland evolution. The factors controlling badland development can be grouped into those related to gross morphology, to surface cover and runoff generation, and to material properties. These factors are effective over varying timescales, implying that morphological response times differ among the selected badlands.

The mountain fluvial systems of southeast Spain involve sediment supply from steep mountain slopes into headwater channels. Alluvial fans often occur where these headwater channels emerge from the mountain areas, and may influence the connectivity of the sediment transport system from the mountain source areas to the main lowland drainages. Critical in this role is whether the alluvial fans are aggrading or dissecting, and whether there is a break or continuity in the channel through the fan environment. Previous work has identified some of the factors influencing the behaviour of the alluvial fans in southeast Spain. This paper deals with the mountain front alluvial fans in the semi-arid areas of Murcia and Almeria provinces. It attempts, by mapping the location of alluvial fans, then their classification into aggrading or dissecting fans, to identify the extent to which the mountain fluvial systems are buffered by aggrading alluvial fans or exhibit channel continuity through the mountain front environment. It further considers the implications of climatically induced changes between aggradational and dissectional behaviour on alluvial fans.

Debris cones and alluvial fans involve a range of landform sizes from individual debris-flow lobes, through debris cones and “classic” alluvial fans, to enormous fluvial “megafans” (Harvey 2011). Within the context of this book the focus is on the intermediate scale, debris cones to “classic alluvial fans”. Such landforms are found in three main settings (Harvey 2010): mountain-front, intra-montane, and tributary-junction settings. They occur in all climatic environments, but again, within the context of this book the focus is on dry-region, and temperate upland and mountain environments.

Hillslope gully development is often controlled by interactions between multiple processes, rather than by individual processes. Such interactions may have both spatial and temporal characteristics. A twenty-year monitoring program of hillslope gullying in the Howgill Fells, northwest England, has identified the roles of both on-slope interactions and slope/stream coupling interactions, which can be related to several temporal scales. On-slope interactions are primarily seasonal, whereas those related to coupling produce a cyclicity over timescales of up to several years. Over the longer term (decades or more) progressive changes in gully morphology modify the nature of both sets of interactions, and through negative feedback mechanisms may ultimately lead to gully stabilisation. Gully development is controlled by the rates of headwall recession and the basal incision/stabilisation behaviour. After basal stabilisation, vegetation encroachment onto the eroding slopes takes place faster than headwall retreat, resulting in a finite age and limiting size for gully development. A simple model based on the current rates of development adequately describes the morphology of modern gullies but is inappropriate when applied to an older generation of stabilised gullies. This suggests that there have been changes in sediment generation and removal rates during the late Holocene.

Previous work on stream channels in upland areas of Britain has demonstrated a close control over channel morphology and stability by the rate of coarse sediment supply from the hillslopes of the catchment. Streams fed by large amounts of coarse sediment develop unstable, wide, often braided channels, whereas those with limited coarse sediment supply develop stable, much narrower, often meandering channels. The sediment supply from hillslopes is controlled by thresholds of hillslope stability, storm event frequency, and the coupling between the hillslopes and the channel. Climatically-induced changes in any of these three factors may have implications for channel morphology and stability. This paper examines these implications in British upland fluvial systems, with particular reference to the Howgill Fells, Cumbria, in the contexts of the adjustment of stream channels to sediment supply from erosional gully systems, and their response to and recovery from major flood events.

Three groups of alluvial terraces together with the modern floodplain mark the Postglacial development of the middle part of the Dane Valley, Cheshire. These are a High terrace group of late Pleistocene age, a Middle terrace group of late Pleistocene to early Holocene age, a Low terrace of mid–late Holocene age, and a modern (post ca. 1840 AD) floodplain. A chronology of erosion, deposition, and landform development since mid-Holocene times is established in this paper on the basis of terrace morphology, stratigraphy, sedimentology, soil analysis, magnetic mineral analysis, and four radiocarbon dates. After dissection of the Middle terrace during the early to mid-Holocene, a long period of lateral activity by the river was followed by a major aggradation phase, which formed the Low terrace surface. This was followed by dissection during the last ca. 300 years and the development of the modern floodplain since ca. 1840 AD. Various explanations for the changes during the Holocene are considered; the Low terrace aggradation appears to be related to a major phase of mediaeval soil erosion.

Gully systems in the catchment of the Barranco de la Clamor, near El Tormillo, Ebro Basin, northern Spain include midslope, valley floor, and basally induced gully systems. The present, system is poorly coupled, with midslope gullies generally petering out without meeting the incised stream network. Even the valley-floor network is poorly integrated, and functions as a serieos of discrete units bounded by major headcuts in resistant sandstone, above which are modern aggradation zones. The modern valley-floor gully pattern is inherited from earlier patterns developed during previous incisional stages of landscape evolution. Through the Holocene the area has switched between incisional and aggradational regimes. Two main fills representing the aggradational phases have been dated to ca. 6000 cal. BP and to the Iron Age, with incision dominating the intervening periods. The regime switches are interpreted to have been climatically induced. The system appears to be vulnerable to regime switching following changes in runoff rates, erosion rates and changes in the coupling characteristics of the system.

Alluvial fans at the front of the Soda Mountains at Zzyzx, in the Mojave Desert, California, have responded differently to late Pleistocene to Holocene climatic changes. The alluvial fans have been mapped in the field and the depositional facies interpreted as debris-flow and fluvial channel and sheetflood sediments. The relative age relationships of the fan segments have been determined primarily on the basis of soil development. The overall sequence has been established in relation to dated shorelines of late Pleistocene pluvial Lake Mojave, and the ages suggested by regional correlations. Six sets of alluvial fan deposits have been identified and labeled, oldest to youngest, Qf0–Qf5. Qf0 and Qf1 sediments predate pluvial Lake Mojave I (18.5–16.5 ka). Qf0 sediments are seen only in sections in fanhead trenches. Soil characteristics and regional correlations suggest an age for Qf0 much greater than for Qf1. Qf1 appears to date from the late Pleistocene, but prior to the Lake Mojave I highstand. Qf2 dates from the period following the Lake Mojave I and II highstands (18.4–16.6–13.7–11.4 ka) but prior to the youngest dated shoreline of pluvial Lake Mojave (10–9.3 ka). Fan depositional phases Qf3–Qf5 postdate the youngest lake shoreline, and are therefore Holocene in age. From the late Pleistocene to the Holocene there was a switch from deposition dominantly by debris-flow to fluvial channel and sheetflood processes, which was accompanied by changes in fan style from fan aggradation to progradation and dissection. However, during the mid Holocene (ca. 4.3–3.5 ka) the Qf4 sediments suggest a shortlived reversal of this trend with a local increase in sedimentation and a short-lived reversion to debris-flow deposition on some fans. Different fans along the mountain front responded differentially to climatic change over the period since the late Pleistocene, with the largest fans switching from debris-flow to fluvial processes first, and some of the smallest fans becoming inactive during the Holocene. The results indicate that the fan processes are controlled by water and sediment supply from the hillslopes, switching as these processes changed in response to climatic changes. There is no evidence for tectonically induced change over this period, and changes in fan geomorphology induced by base-level change are restricted to the toe areas of some fans. At the local level, topographic catchment thresholds control the response of individual fans to climatically induced changes in runoff and sediment supply. Harvey, A.M., and Wells, S.G., 2003, Late Quaternary variations in alluvial fan sedimentologic and geomorphic processes, Soda Lake basin, eastern Mojave Desert, California, in Enzel, Y., Wells, S.G., and Lancaster, N., eds., Paleoenvironments and paleohydrology of the Mojave and southern Great Basin Deserts: Boulder, Colorado, Geological Society of America Special Paper 368, p. 207–230. © 2003 Geological Society of America.