Quaternary glaciation of the North Slope of Karakorum mountains

Three kinds of moraines can be found in the Muztagh valley on the N slope of Mount K2, Karakorum: an old calco-cement moraine lying at the altitude of 5000 m asl, a hilly moraine lying at the altitude of 4200–4800 m asl and a new lateral moraine, lying on both sides of the present river valley. According to the moraines’ geomorphology, they are referred to the Middle Pleistocene Glaciation, the Late Pleistocene Glaciation and the Post-Glacial Period respectively. The lowest level of glacial cirques at 4200–4000 m asl, corresponding to the largest Glaciation, belongs to the Middle Pleistocene (Riss). The ancient cirques at this altitude in the Shaksgam and Yargand valleys are poorly preserved while at the piedmont of the West Kunlun mountains they are represented in better shape. This means that these ancient cirques had been submerged and almost removed by the main ice flow of the valleys. Old cirques, however, are well shaped (or reshaped) where associated with younger cirques at 4600 m als; they could be considered as the product of the Last Glaciation (Würm). Thus, the equilibrium line altitude (ELA) decreased to 1600 m during the Riss Glaciation and to 1000 m during the Würm Glaciation. On the basis of the ELA decrease and existence of complex morainic deposits found at the piedmont of the West Kunlun mountains at about 2200 m asl, the author adheres to the opinion that Riss Glaciation had developed an ice cover (ice sheet), with the central ice area located in Karakorum and reaching up to the high peaks of the Kunlun mountains, and down to the piedmont region. During the Last Glaciation an immense ice cap covered the upper parts of the Shaksgam and Yarkant valleys. The paper also deals with the relations between glaciations and tectonic uplift, indicating that topographic and climatic conditions were favourable for the large-scale ice development in the Middle and Late Pleistocene. The uplift may have reached 600–800 m during the Postglacial period. The uplift rates are often reflected by the glaciostatic in the Postglacial Age.     

Spatial analysis of cirques from three regions of Iceland: implications for cirque formation and palaeoclimate

This study is a quantitative analysis of cirques in three regions of Iceland: Tröllaskagi, the East Fjords and Vestfirðir. Using Google Earth and the National Land Survey of Iceland Map Viewer, we identified 347 new cirques on Tröllaskagi and the East Fjords region, and combined these data with 100 cirques previously identified on Vestfirðir. We used ArcGIS to measure length, width, aspect, latitude and distance to coastline of each cirque. Palaeo‐equilibrium‐line altitudes (palaeo‐ELAs) of palaeo‐cirque glaciers were calculated using the altitude‐ratio method, cirque‐floor method and minimum‐point method. The mean palaeo‐ELA values in Tröllaskagi, the East Fjords and Vestfirðir are 788, 643 and 408 m a.s.l, respectively. Interpolation maps of palaeo‐ELAs demonstrate a positive relationship between palaeo‐ELA and distance to coastline. A positive relationship between palaeo‐ELA and latitude is observed on Vestfirðir, a negative relationship is observed on Tröllaskagi and no statistically significant relationship is present on the East Fjords. The modal orientation of cirques on Tröllaskagi and Vestfirðir is northeast, while orientation of cirques in the East Fjords is north. Palaeo‐wind reconstructions for the LGM show that modal aspect is aligned with the prevailing north‐northeast wind directions, although aspect measurements demonstrate wide dispersion. Cirque length is similar on Tröllaskagi and the East Fjords, but cirques are approximately 200 m shorter in Vestfirðir. Cirque widths are similar in all three regions. Comparisons with a global data set show that cirques in Iceland are smaller and more circular than cirques in other regions of the world. Similar to glaciers in Norway and Kamchatka, our results demonstrate that access to a moisture source is a key parameter in determining palaeo‐ELAs in Iceland. Temperatures interpreted from palaeo‐ELA depressions suggest that these cirques may have been glaciated as recently as the Little Ice Age.     

GIS analysis of cirques on Vestfirðir,northwest Iceland: implications for palaeoclimate

This study presents the first regional analysis of cirques on Vestfirðir, NW Iceland, using a Geographical Information System (GIS). The length, width, elevation of cirque‐floor, latitude and the distance to the modern coastline (both ocean and fjord coastlines) of cirques were quantified using ArcGIS. The topographical analysis revealed a total of 100 cirques on western and northern Vestfirðir. Several additional cirques are present, but they had poorly defined toewalls, making the cirque‐floor difficult to identify. Mean cirque length is 515 m and mean cirque width is 752 m. The modal orientation of the aspect of cirques is northeast, with a strong secondary mode to the northwest. Cirques at low elevations are more abundant close to the ocean, whereas cirques further from the ocean are present at high elevations. Three techniques were used to reconstruct past equilibrium‐line altitudes (ELAs) of cirque glaciers: the cirque‐floor method, the altitude‐ratio method and the accumulation‐area ratio method. The largest range of past ELAs is generated from the cirque‐floor method with values from 40 up to 730 m. Mean past ELA values range from ～395 to 423 m depending on the method used to reconstruct former ELAs. A strong positive relationship is observed between past ELA values and distance to the ocean demonstrating the importance of access to a moisture source for glacier survival. This relationship is stronger than the relationship between former ELAs and latitude. Based on the small size of cirque glaciers, it is likely that even minor fluctuations in the Irminger Current and the East Greenland Current influence cirque glaciation on Vestfirðir.     

Late Quaternary glaciation in the Nun‐Kun massif,northwestern India

The late Quaternary glacial history of the Nun‐Kun massif, located on the boundary between the Greater Himalaya and the Zanskar range in northwestern India, was reconstructed. On the basis of morphostratigraphy and ¹⁰Be dating of glacial landforms (moraines and glacial trimlines), five glacial stages were recognized and defined, namely: (i) the Achambur glacial stage dated to Marine Oxygen Isotope Stage 3 to 4 (38.7–62.7 ka); (ii) the Tongul glacial stage dated to the early part of the Lateglacial (16.7–17.4 ka); (iii) the Amantick glacial stage dated to the later part of the Lateglacial (14.3 ka, 11.7–12.4 ka); (iv) the Lomp glacial stage dated to the Little Ice Age; and (v) the Tanak glacial stage, which has the youngest moraines, probably dating to the last few decades or so. Present and former equilibrium‐line altitudes (ELAs) were calculated using the standard area accumulation ratio method. The average present‐day ELA of ～4790 m above sea level in the Greater Himalaya is lower than those in the Ladakh and Zanskar ranges, namely 5380 and ～5900 m a.s.l., respectively. The ELA in the Zanskar range is higher than in the Ladakh range, possibly due to the higher peaks in the Ladakh range that are able to more effectively capture and store snow and ice. ELA depressions decrease towards the Ladakh range (i.e. inner Plateau). Peat beds interbedded with aeolian deposits that cap the terminal moraine of Tarangoz Glacier suggest millennial‐time‐scale climate change throughout the Holocene, with soil formation times at c. 1.5, c. 3.4 and c. 5.2 ka, probably coinciding with Holocene abrupt climate change events. Given the style and timing of glaciation in the study area, it is likely that climate in the Nun‐Kun region is linked to Northern Hemisphere climate oscillations with teleconnections via the mid‐latitude westerlies.     

Lateglacial and early Holocene surface exposure ages of glacial boulders in the Taiwanese high mountain range

Glacial landforms and sediments mapped in three presently unglaciated mountain massifs, the Nanhuta Shan, the Hsueh Shan and the Yushan, support the concept of repeated, multi-stage glaciations in the Taiwanese high mountain range during the late Pleistocene. New results from surface exposure dating using in situ produced cosmogenic ¹⁰Be measured in samples taken from erratic and moraine boulders in Nanhuta Shan at altitudes between 3100 and 3500 m are presented here. The results confirm independent and previously reported Optically Stimulated Luminescence (OSL) ages and ¹⁰Be exposure ages from glacial deposits in the same area and suggest a Lateglacial and early Holocene glaciation, the so called Nanhuta glacier advance with two substages at about 12–15 ka and 9.5 ka BP. The respective equilibrium line altitudes (ELA) were calculated at 3340 m and 3440 m with corresponding ELA depressions of 610 ± 100 m and 510 ± 100 m relative to the present day (theoretical) ELA, which is estimated to be at about 3950 ± 100 m in Taiwan. Large-scale erosional landforms indicate a much wider glacier extent during an earlier stage, which is not dated in Nanhuta Shan so far. Luminescence dating from near Hsueh Shan suggests an age of marine isotope stage (MIS) 4 for this stage.     

Nunataks of the last ice sheet in northwest Scotland

High-level weathering limits separating ice-scoured topography from an upper zone of frost-weathered detritus were identified on 17 mountains in NW Scotland at altitudes of <600 m to< 900 m, and a further 6 peaks were found to support evidence of ice scouring to summit level. Weathering limits are most clearly defined on Torridon Sandstone, which is resistant to frost shattering, but can also be mapped on Cambrian Quartzite, Lewisian Gneiss and Moine Schist. Contrasts in degree of rock surface weathering above and below the weathering limits were evaluated using measurements of joint depth and rock surface hardness, and through X-ray diffraction analyses of clay mineral assemblages. The results indicate significantly more advanced rock and soil weathering above the weathering limits. Widespread persistence of gibbsite above the weathering limits suggests that they represent the upper limit of Late Devensian glacial erosion, and the regularity of the decline in weathering limit altitude along former flowlines eliminates the possibility that it represents a former thermal boundary between protective cold-based and erosive warm-based ice. The weathering limits are therefore interpreted as periglacial trimlines defining the maximum surface altitude of the last ice sheet around former nunataks. Calculated basal shear stresses of 50–78 kPa are consistent with this interpretation. The altitude of the trimlines implies that the former ice shed lay at 900–930 m in the Fannich Mountains and descended gently northwards, and that the ice surface descended NW from the ice shed to >500 m over the extreme NW tip of Scotland and to 700–730 m at the head of Little Loch Broom.     

Mountain glaciation and paleoclimate reconstruction in the Picos de Europa (Iberian Peninsula,SW Europe)

Geomorphic mapping and stratigraphic analysis of a lake core document the late Quaternary glacial history of the Central and Eastern Massifs of the Picos de Europa, northwestern Spain. The distribution of glacial deposits indicates that at their most advanced positions glaciers occupied 9.1 km², extended as far as 7 km down-valley and had an estimated equilibrium-line altitude (ELA) ranging between 1666 and 1722 m. Radiocarbon dating of sediment deposited in a lake dammed by moraines of this advance show that the maximum glacial extent was prior to 35,280 ± 440 cal yr BP. This advance was followed by two subsequent but less extensive late Pleistocene advances, recorded by multiple moraines flanking both massifs and sedimentary characteristics in the lake deposits. The last recognized glacial episode is the 19th-century maximum extent of small Little Ice Age glaciers in the highest cirques above 2200 m.     

Late Quaternary glacial chronology on Nevado Illimani, Bolivia, and the implications for paleoclimatic reconstructions across the Andes

¹⁰Be terrestrial cosmogenic nuclide surface exposure ages from moraines on Nevado Illimani, Cordillera Real, Bolivia suggest that glaciers retreated from moraines during the periods 15.5-13.0 ka, 10.0-8.5 ka, and 3.5-2.0 ka. Late glacial moraines at Illimani are associated with an ELA depression of 400-600 m, which is consistent with other local reconstructions of late glacial ELAs in the Eastern Cordillera of the central Andes. A comparison of late glacial ELAs between the Eastern Cordillera and Western Cordillera indicates a marked change toward flattening of the east-to-west regional ELA gradient. This flattening is consistent with increased precipitation from the Pacific during the late glacial period.     

Glacial and periglacial buzzsaws: fitting mechanisms to metaphors

The buzzsaw hypothesis refers to the potential for glacial and periglacial processes to rapidly denude mountains at and above glacier Equilibrium Line Altitudes (ELAs), irrespective of uplift rates, rock type or pre-existing topography. Here the appropriateness of the buzzsaw metaphor is examined alongside questions of the links between glacial erosion and ELAs, and whether the glacial system can produce low-relief surfaces or limit summit heights. Plateau fragments in mountains on both active orogens and passive margins that have been cited as products of glacial and periglacial buzzsaw erosion instead generally represent dissected remnants of largely inherited, pre-glacial relief. Summit heights may correlate with ELAs but no causal link need be implied as summit erosion rates are low, cirque headwalls may not directly abut summits and, on passive margins, cirques are cut into pre-existing mountain topography. Any simple links between ELAs and glacial erosion break down on passive margins due to topographic forcing of ice-sheet growth, and to the km-scale vertical swaths through which ELAs have shifted through the Quaternary. Glaciers destroy rather than create low-relief rock surfaces through the innate tendency for ice flow to be faster, thicker and warmer along valleys. The glacial buzzsaw cuts down.     

Sensitivities of the equilibrium line altitude to temperature and precipitation changes along the Andes

Equilibrium line altitudes (ELAs) of alpine glaciers are sensitive indicators of climate change and have been commonly used to reconstruct paleoclimates at different temporal and spatial scales. However, accurate interpretations of ELA fluctuations rely on a quantitative understanding of the sensitivity of ELAs to changes in climate. We applied a full surface energy- and mass-balance model to quantify ELA sensitivity to temperature and precipitation changes across the range of climate conditions found in the Andes. Model results show that ELA response has a strong spatial variability across the glaciated regions of South America. This spatial variability correlates with the distribution of the present-day mean climate conditions observed along the Andes. We find that ELAs respond linearly to changes in temperature, with the magnitude of the response being prescribed by the local lapse rates. ELA sensitivities to precipitation changes are nearly linear and are inversely correlated with the emissivity of the atmosphere. Temperature sensitivities are greatest in the inner tropics; precipitation becomes more important in the subtropics and northernmost mid-latitudes. These results can be considered an important step towards developing a framework for understanding past episodes of glacial fluctuations and ultimately for predicting glacier response to future climate changes.     

The Loch Lomond Readvance on the Isle of Skye,Scotland: Glacier reconstruction and palaeoclimatic implications

Geomorphological mapping of southern Skye indicates evidence for a single readvance of locally-nourished glaciers. These comprised a major icefield that occupied c. 155 km² of the main mountain area, a small icefield c. 10 km² in extent in the Kyleakin hills and ten corrie glaciers with a total area of c. 16 km². The absence of Lateglacial pollen sites, shorelines and periglacial features within the limits of local glaciation implies a Loch Lomond Readvance age for this glacial event. The area-weighted mean equilibrium line altitude (ELA) of the reconstructed Loch Lomond Readvance glaciers (319 m) conforms with a regional eastwards rise in ELAs that indicates dominant westerly airstreams during the Loch Lomond Stadial. An easterly decline in ELAs across the former icefields is interpreted in terms of easterly transfer of snow across ice-sheds by westerly winds, though the altitudes of corrie glacier ELAs suggest that the dominant snow-bearing winds were southerlies. Calculations based on the area-weighted mean ELA for the major icefield (308 m) indicate a stadial mean July sea-level temperature of c. 6 °C. The anomalously low gradients of certain former icefield outlet glaciers are attributed to deformation of subglacial sediment, an effect that may vitiate the assumption of linear ablation/accumulation gradients in the calculation of former ELAs for reconstructed glaciers.     

Fluctuations of the Deming Glacier and theoretical equilibrium line altitudes during the Late Pleistocene and Early Holocene on Mount Baker, Washington, USA

Kovanen, D. J. & Slaymaker, O. 2005 (May): Fluctuations of the Deming Glacier and theoretical equilibrium line altitudes during the Late Pleistocene and Early Holocene on Mount Baker, Washington, USA. Boreas , Vol. 34, pp. 157–175. Oslo. ISSN 0300–9483.
The Deming Glacier is presently nourished by an ice-cap type accumulation area on Mount Baker (3285 m a.s.l.). The specific meso-scale (>10km) form and isolation of the Mount Baker stratovolcano seem to influence temperature and precipitation gradients (contemporary climate data). These data are used as a reference when calculating paleo-equilibrium-line altitudes (ELAs). Six radiocarbon dates are reported, between 10 680 70 and 10 500 70 ¹⁴C yr BP (12 903–12 183 cal. yr BP) from detrital logs in drift that were buried during an advance of the Deming Glacier (altitude 3230–1158 m) during possibly the Younger Dryas interval. The calculated range of theoretical ELA depressions (ΔELA) relative to modern is 400–355 m using two different methods. Assuming no change in precipitation, ablation-season temperature would have been 2.5–2.2C cooler, which is consistent with other paleoclimatic reconstructions in this region. Alternatively, assuming that the modern reference climate is appropriate, and based on regressions of modern-day glacial conditions, the predicted mean winter precipitation necessary to support the former Deming Glacier was in the order of 200–150% (mean 175%) or 119–86% (mean 103%). This amount of precipitation could result from reinvigorated moisture transport into the North Cascades and increased seasonality at the end of the last glaciation.     

Late Quaternary glaciation and equilibrium-line altitudes of the Mayan Ice Cap, Guatemala, Central America

The Sierra los Cuchumatanes (3837 m), Guatemala, supported a plateau ice cap and valley glaciers around Montaña San Juan (3784 m) that totaled ∼ 43 km² in area during the last local glacial maximum. Former ice limits are defined by sharp-crested lateral and terminal moraines that extend to elevations of ∼ 3450 m along the ice cap margin, and to ca. 3000-3300 m for the valley glaciers. Equilibrium-line altitudes (ELAs) estimated using the area-altitude balance ratio method for the maximum late Quaternary glaciation reached as low as 3470 m for the valley glaciers and 3670 m for the Mayan Ice Cap. Relative to the modern altitude of the 0°C isotherm of ∼ 4840 m, we determined ELA depressions of 1110-1436 m. If interpreted in terms of a depression of the freezing level during maximal glaciation along the modern lapse rate of − 5.3°C km^− 1, this ΔELA indicates tropical highland cooling of ∼ 5.9 to 7.6 ± 1.2°C. Our data support greater glacial highland cooling than at sea level, implying a high tropical sensitivity to global climate changes. The large magnitude of ELA depression in Guatemala may have been partially forced by enhanced wetness associated with southward excursions of the boreal winter polar air mass.     

太白山第四纪冰碛物特征与冰期

在晚更新世早期(Q_3~1)和晚期(Q_8~3),太白山主峰八仙台先后发生过两次冰川作用,即三爷海冰期和太白冰期。其中太白冰期又可划分为早太白和晚太白两个副冰期。经人工剖面证实的三道不同时期的侧碛垄分别与上述冰期相对应。各种冰蚀地貌都受到该区构造的控制和影响。     

Progressive glacial retreat in the Southern Altiplano (Uturuncu volcano, 22°S) between 65 and 14 ka constrained by cosmogenic He dating

This work presents the first reconstruction of late Pleistocene glacier fluctuations on Uturuncu volcano, in the Southern Tropical Andes. Cosmogenic ³He dating of glacial landforms provides constraints on ancient glacier position between 65 and 14 ka. Despite important scatter in the exposure ages on the oldest moraines, probably resulting from pre-exposure, these ³He data constrain the timing of the moraine deposits and subsequent glacier recessions: the Uturuncu glacier may have reached its maximum extent much before the global LGM, maybe as early as 65 ka, with an equilibrium line altitude (ELA) at 5280 m. Then, the glacier remained close to its maximum position, with a main stillstand identified around 40 ka, and another one between 35 and 17 ka, followed by a limited recession at 17 ka. Then, another glacial stillstand is identified upstream during the late glacial period, probably between 16 and 14 ka, with an ELA standing at 5350 m. This stillstand is synchronous with the paleolake Tauca highstand. This result indicates that this regionally wet and cold episode, during the Heinrich 1 event, also impacted the Southern Altiplano. The ELA rose above 5450 m after 14 ka, synchronously with the Bolling–Allerod.     

A preliminary inventory of periglacial landforms in the Andes of La Rioja and San Juan, Argentina, at about 28°S

The Cerro El Potro and nearby mountain chains belong to the Andean Frontal Cordillera (28°S). Cerro El Potro is a glaciated mountain that is surrounded by huge valleys both on its Chilean and Argentinean flanks. Its southern limit is a steep rock wall towards the trough-shaped Río Blanco valley in Argentina, with a wide valley floor. The other sides of the mountain are characterized by well-developed Pleistocene cirques. The predominant landforms in this area have been shaped in a periglacial environment superimposed on an earlier glacial landscape. It is a region with abundant rock glaciers, a noteworthy rock glacier zone, but nevertheless, it is a relatively little known area in South America. In this preliminary inventory, the landforms surveyed were mainly gravitational in origin, including valley rock glaciers, talus rock glaciers, debris cones, landforms originated by solifluction processes and talus detrital sheets on mountain sides. Ancient moraine deposits have been found on the sides of the main rivers that cross the area form west to east, including the Blanco and Bermejo rivers. Present day fluvial activity is limited, and restricted to these main rivers. In this area of glacial valleys and small cirques, there are small lakes and other water bodies, grass covered patches and zones with high mountain vegetation. Present day glacial activity is restricted to the highest part of the area, above 5500 m a.s.l., mainly in the Cerro El Potro (5879 m) where a permanent ice field exists, as well as small mountain glaciers.     

青藏高原东北缘玛雅雪山晚第四纪冰川发育的气候和构造耦合

青藏高原东北缘的玛雅雪山(海拔4 447 m)保存着确切的第四纪冰川遗迹. 野外地貌调查与光释光测年方法相结合, 确认玛雅雪山晚第四纪主要经历3次冰川作用: 第Ⅰ组冰碛时代为新冰期; 第Ⅱ组冰碛物年龄为(23.2±1.0)ka, 其上覆泥石流年龄为(2.9±0.3)~(2.3±0.1)ka, 上层土壤年龄为(3.6±0.2)ka, 对应于深海氧同位素2阶段(MIS 2)的末次冰盛期(LGM); 第Ⅲ组冰碛年龄为(42.6±1.9)~(45.7±3.0) ka, 属于末次冰期中冰阶, 对应MIS 3中期. 采用最新综合因子法计算玛雅雪山现代冰川物质平衡线为海拔4 605 m. 依据冰川地貌形态, 计算末次冰期平衡线为海拔3 800 m. 通过庄浪河阶地的拔河高度及各级阶地的年代, 以河流的下切速率代表玛雅雪山的抬升速率, 计算得到末次冰期中期以来玛雅雪山抬升了50~60 m. 利用玛雅雪山周边的达里加山和太白山冰川漂砾的¹⁰Be 数据近似代表流域侵蚀速率, 推算出玛雅雪山剥蚀速率大约为29 mm·ka^-1, 推断MIS 3以来流域的剥蚀量为1~2 m. 综合末次冰期中期以来的构造抬升量和剥蚀量, 恢复末次冰期中期时的流域高度为海拔4 200 m, 平衡线高度为海拔3 750 m. 研究结果显示: 研究区在MIS 3时, 流域平均高度已经在平衡线之上, 在流域平均高度到主峰之间冰川开始积累, 发育冰川. 结合其他环境指标综合推断, 玛雅雪山晚第四纪冰川的发育是气候和构造耦合的产物.     

Should Quaternary sea-level changes be used to correct glacier ELAs, vegetation belt altitudes and sea level temperatures for inferring climate changes?

Changes in the altitudes of glacier snowlines (ELAs) and the altitudes of montane vegetation belts (VBAs) measure Quaternary climatic change. An accepted ‘correction’ to such changes by deducting the amount of contemporary sea level fall is wrong, since the air displaced by the ice sheets approximately fills the space left by the falling sea level and so there is no overall downward movement of the troposphere. This also causes a reduced cooling at the lowered sea level relative to that at the former inter-glacial sea level, about 1°C at the Las Glacial Maximum, which reduces the discrepancies previously noted by others between terrestrial and marine estimates of sea-level cooling. The change in temperature is indicated by the product of the ELA or VBA lowering and the environmental lapse rate (ELR). Prior estimates of ΔELA (−900 ± 135 m) and ELR (−6° ± 0.1°C km⁻¹) would indicate a cooling of −5.4°C at interglacial sea level and −4.4°C at glacial sea level, although glacial-period ELRs are not known reliably. Established ELA corrections for local epeirogenic uplift or subsidence are appropriate.     

Late Quaternary landscape development along the Rancho Marino coastal range front (south‐central Pacific Coast Ranges,California, USA)

Late Quaternary landscape development along the Rancho Marino coastal range front in the central‐southern Pacific Coast Ranges of California has been documented using field mapping, surveying, sedimentary facies analysis and a luminescence age determination. Late Quaternary sediments along the base of the range front form a single composite marine terrace buried by alluvial fans. Marine terrace sediments overlie two palaeoshore platforms at 5 m and 0 m altitude. Correlation with the nearby Cayucos and San Simeon sites links platform and marine terrace development to the 125 ka and 105 ka sea‐level highstands. Uplift rate estimates based on the 125 ka shoreline angle are 0.01–0.09 m ka^?1 (mean 0.04 m ka^?1), and suggest an increase in regional uplift along the coast towards the NW where the San Simeon fault zone intersects the coastline. Furthermore, such low rates suggest that pre‐125 ka uplift was responsible for most of the relief generation at Rancho Marino. The coastal range front landscape development is, thus, primarily controlled by post 125 ka climatic and sea‐level changes. Post 125 ka sea‐level lowering expanded the range front piedmont area to a width of 7.5 km by the 18 ka Last Glacial Maximum lowstand. This sea‐level lowering created space for alluvial fan building along the range front. A 45 ± 3 ka optically stimulated luminescence (OSL) age provides a basal age for alluvial fan building or marks the time by which distal alluvial fan sedimentation has reached 300 m from the range front slope. Fan sedimentation is related to climatic change, with increased sediment supply to the range front occurring during (1) glacial period cold stage maxima and/or (2) the Late Pleistocene–Holocene transition, when respective increases in precipitation and/or storminess resulted in hillslope erosion. Sea‐level rise after the 18 ka lowstand resulted in range front erosion, with elevated localised erosion linked to the higher relief and steeper slopes in the SE. This study demonstrates that late Quaternary coastal range front landscape development is driven by interplay of tectonics, climatic and sea‐level change. In areas of low tectonic activity, climatic and sea‐level changes dominate coastal landscape development. When the sea‐level controlled shoreline is in close proximity to the coastal range front, localised patterns of sedimentation and erosion are passively influenced by the pre‐125 ka topography. Copyright © 2008 John Wiley & Sons, Ltd.