paleogeographic and paleoenvironmental evolution in northwestern santa cruz argentina and its influence on human occupation dynamics during the late pleistocene early holocene abstract the climatic changes that occurred during the late pleistocene early holocene in patagonia generated a glacial retreat which brought along with it the formation of proglacial lakes in contact with ice and periglacial lakes in areas close to the glaciers the bathymetric fluctuations of lacustrine systems throughout time have favored new areas available for population circulation and settlement our results showed the influence of ice masses on the palaeoenvironmental evolution with alternating glacial and proglacial environments tillites glacilacustrine lacustrine environments glacifluvial fluvial environments alluvial fans and deltaic bodies an initial diachronism was recorded in the formation of the paleolakes the lacustrine system parque nacional perito moreno sl pnpm would have begun to form first and then the lacustrine system pueyrredon posadas salitroso sl pps between 12 and 11 7 kyr in both sectors the paleolakes would have reached their maximum areal extension after 10 kyr a regression and separation of the lacustrine systems until the acquisition of its current configuration was interpreted this data coincides with archaeological sites located at lower elevations closer to the current level of the coastline both in the sl pps and the sl pnpm areas the palaeoenvironmental information indicated a synchrony in both areas in the evolution of the floristic landscape the separation of lacustrine systems generated new available spaces and ecological niches for the establishment of vegetation which encouraged a greater heterogeneity in vegetation that could have been exploited by hunter gatherer groups

the evolution of the patagonian ice sheet from 35 ka to the present day patice abstract we present patice a gis database of patagonian glacial geomorphology and recalibrated chronological data patice includes 58 823 landforms and 1 669 geochronological ages and extends from 38 s to 55 s in southern south america we use these data to generate new empirical reconstructions of the patagonian ice sheet pis and subsequent ice masses and ice dammed palaeolakes at 35 ka 30 ka 25 ka 20 ka 15 ka 13 ka synchronous with the antarctic cold reversal 10 ka 5 ka 0 2 ka and 2011 ad at 35 ka the pis covered of 492 6 x103 km2 had a sea level equivalent of 1 496 mm was 350 km wide and 2090 km long and was grounded on the pacific continental shelf edge outlet glacier lobes remained topographically confined and the largest generated the suites of subglacial streamlined bedforms characteristic of ice streams the pis reached its maximum extent by 33 28 ka from 38 s to 48 s and earlier around 47 ka from 48 s southwards net retreat from maximum positions began by 25 ka with ice marginal stabilisation then at 21 18 ka which was then followed by rapid irreversible deglaciation by 15 ka the pis had separated into disparate ice masses draining into large ice dammed lakes along the eastern margin which strongly influenced rates of recession glacial readvances or stabilisations occurred at least at 14 13 ka 11 ka 6 5 ka 2 1 ka and 0 5 0 2 ka we suggest that 20th century glacial recession a 1 is occurring faster than at any time documented during the holocene

a record from lake cardiel of climate change in southern south america southern south america the only continental land mass lying between 38 s and the antarctic circle presents a rare opportunity to reconstruct terrestrial records of palaeoclimate in an area that is subject to shifts of polar and mid latitude wind and pressure belts in the bulk of this region patagonia are many hydrographically closed lakes which despite the palaeoclimatic significance of the region and the proven utility of lake level records in reconstructing past climates1 2 have escaped detailed study using sedimentary and geomorphic evidence together with 14c dating we present here a detailed lake level record for lake cardiel fig 1 the highest level of the past 21 000 years occurred at about 9 780 bp reminiscent of tropical lakes rather than those in northern mid latitudes1 2 the lake cardiel record corroborates and clarifies the timing of the wetness record inferred from pollen studies in patagonia

scratching the surface estimating dimensions of large igneous provinces a study of five major basaltic provinces including oceanic plateaus volcanic passive margins and continental flood basalts shows that they are voluminous constructions of extrusive igneous rock underlain by intrusive rock crustal thickness ranges from 20 to 40 km and lower crust is characterized by high 7 0 7 6 km s seismic velocities volumes and emplacement rates derived for two oceanic plateaus the ontong java and kerguelen broken ridge reveal short lived pulses of increased global crustal production and suggest an origin involving the lower mantle the ontong java rate of emplacement may have exceeded the contemporaneous global production rate of the entire mid ocean ridge system despite the importance off large igneous provinces in studies of mantle dynamics and the global environment scarce age and deep crustal data necessitate intensified efforts in seismic imaging and scientific drilling in a range of such features

chronology of bathymetric variations of the pueyrredon posadas salitroso lacustrine system during the late pleistocene to early holocene abstract the pueyrredon posadas salitroso lacustrine system pps ls is located in the andean patagonia region of argentina 47 22 28 s 71 55 34 w and represents a series of lakes formed as glaciers retreated during the late pleistocene and early holocene these lakes began as proglacial lakes and later evolved into periglacial lakes this research presents the chronological evolution of the pps ls bathymetric variations based on the analysis of stratigraphic profiles surveyed at different locations and the dates obtained from lake sediments four paleogeographic sketches representing the chronological evolution of the pps ls between 23 580 bp and 5208 bp have been developed based on the integration of these data

paleogeographic reconstruction of the tar san martin lacustrine system during late pleistocene to early holocene landscape availability and hunter gatherer circulation santa cruz argentina abstract this paper presents the paleogeographic reconstructions of flooded areas of the tar san martin lacustrine system during the late pleistocene holocene the dimensions of lacustrine and glaciolacustrine levels of this basin are higher than the current levels of the lakes the organic matter of lake levels recorded on stratigraphic profiles was described sampled and dated using ams while other paleobathymetric indicators were also identified height of the fan delta apex and paleo coast levels deriving out of the reconstruction of flooded areas it was established that the lake system was formed before 28 ka ago and would have reached its maximum expansion around 12 ka ago the first hunter gatherer occupation of the basin 11 ka corresponds to the period of initial contraction of the lake system and the composition of the current configuration of the coastlines this scenario would have allowed the exploration of western areas and the gradual incorporation of the forest to the action range of hunter gatherer populations similarly the levels of lakes tar and san martin would not have hindered the movement of human populations through the steppe throughout the holocene

geomorphic records along the general carrera chile buenos aires argentina glacial lake 46 48 s climate inferences and glacial rebound for the past 7 9 ka a reply we present geomorphic stratigraphic and chronological data acquired along the general carrera buenos aires gcba glacial lake located along a major morphological incision across the andes complementing relevant available data relative chronology of morpho climatic records together with 18 10be cosmic ray exposure cre ages allow constraining the timing of the patagonian ice sheet fluctuations since the lgm it improves the knowledge of the patagonia climate evolution in the 46 48 s area and allows documenting the uplift rates glacial rebound for the past 7 9 ka the first major ice lobe retreat occurred after 17 3 0 6 ka and has likely continued during the acr from 12 9 to 14 5 ka between 12 9 ka and 10 9 1 3 ka the general carrera lake evolved as an endorheic basin terraces t4 to t1 top to bottom have recorded abrupt lake regressions likely controlled by rainfall deficit they have accumulated in the time interval 17 3 12 3 ka maximum limits two glacial re advances at 10 9 1 3 and 7 9 1 1 ka marked a major climate change that led the lake to be ice dammed again a major transgression occurred subsequently that have flooded the previously accumulated terraces since then a pervasive regression has steered the gcba lake to the situation at present the highest shoreline of the transgression is used as a passive marker in order to quantify the magnitude and character of the regional deformation at 72 30 w the gcba lake area uplifted glacial rebound at a rate between 15 to 33 5 mm yr 1 during the past 7 9 1 1 ka we infer that the high uplift rate mainly originates from the north patagonian icefield ice loss

the chronology of the last glacial maximum and deglacial events in central argentine patagonia this paper evaluates the chronology of the last glacial cycle and deglaciation in the lago pueyrredon valley of central patagonia 47 5 s argentina the valley was a major outlet of the former patagonian ice sheet and the moraines that record its fluctuations are an important proxy record of climate change in southern south america such moraines are well preserved in the lago pueyrredon valley owing in part to the semi arid environment east of the mountain front here we provide the first direct chronology for the age of the rio blanco moraine system by utilizing cosmogenic nuclide surface exposure ages boulders on the moraines give 10be exposure ages that indicate the last glacial maximum lgm maximum extent occurred by 27 25 ka subsequent advances occurred at 23 22 ka 20 18 ka and ca 18 17 ka initial deglaciation began after ca 18 17 ka and was interrupted as evidenced by the lago columna moraines up valley subsequently the outlet glaciers occupying both the lago pueyrredon basin chilean name lago cochrane and the lago buenos aires basin chilean name lago general carrera to the north rapidly retreated more than 80 km at around 16 5 15 ka the timing of the lgm maximum extent and the onset of deglaciation occurred broadly synchronously throughout patagonia deglaciation resulted in a series of interconnected glacier dammed lakes in the region that initially drained toward the atlantic ocean and later drained to the pacific ocean as a consequence of disintegrating ice in the andes

luminescence dating of glacial advances at lago buenos aires 46 s patagonia abstract understanding the timing of past glacial advances in patagonia is of global climatic importance because of the insight this can provide into the influence on glacier behaviour of changes in temperature and precipitation related to the southern westerlies in this paper we present new luminescence ages determined using single grains of k feldspar from proglacial outwash sediments that were deposited by the patagonian ice sheet around lago buenos aires 46 s east of the contemporary northern patagonian icefield the new luminescence ages indicate that major outwash accumulations formed around 110 20 ka to 140 20 ka and that these correspond to the moreno i and ii moraine ridges which were previously dated using cosmogenic isotope dating to 150 30 ka luminescence dating at lago buenos aires has also identified outwash sediments that were deposited during glacial advances 30 8 5 7 ka and 34 0 6 1 ka mis 3 that are not recorded in the moraine record younger outwash accumulations were then deposited between 14 7 2 1 and 26 2 1 6 ka which correspond to the fenix i v moraine ridges the combined chronology suggests that glacial advances occurred 110 20 ka to 150 30 ka mis 6 30 8 5 7 ka to 34 0 6 1 ka mis 3 and 14 7 2 1 to 26 2 1 6 ka mis 2 at lago buenos aires overall luminescence dating using single grains of k feldspar has excellent potential to contribute towards the ever increasing geochronological dataset constraining the timings of glacial advances in patagonia

tectonic significance of mafic volcanic rocks in a mesozoic sequence of the menderes massif west turkey the mesozoic platform sequence of the menderes massif consists of thick succession of detrital and carbonate rocks in this sequence there are mafic metavolcanic rocks at two different levels the first level of mafic metavolcanic intercalations is in the late triassic detrital rich series located in the caltasi formation which is the lowermost unit of the mesozoic platform the second level of the mafic metavolcanic rocks is located in the late cretaceous paleocene selcuk formation laying on top of the platform sequence the caltasi formation which is composed of mica schists thinly bedded cherts calc schist and mafic volcanic intercalations unconformably overlie the bayindir formation which consists of mica schists phyllites and white quartzites of palaeozoic or probably older age the mafic volcanic rocks in the caltasi formation are alkaline basalts with within plate characteristics and are formed during an intraplate extension the caltasi formation is conformably overlain by the kayaalti formation represented by calc schists dolomitic marbles and rudist and emery bearing massive marbles in ascending order the selcuk formation overlies the kayaalti formation and consists of a mica schist matrix with allochthonous blocks of mafic volcanic rocks metaperidotites metagabbros and massive marbles the mafic volcanic rocks in the selcuk formation are tholeiitic basalts and are petrologically similar to mid oceanic basalts the geological and geochemical characteristics of the mafic metavolcanic rocks in the caltasi formation indicate that during the late triassic the menderes platform was segmented probably by the opening of a branch of the neotethyan ocean between the late triassic and the late cretaceous the menderes carbonate platform was built up during the latest cretaceous early paleocene a slab of oceanic crust obducted on this platform and provided slices of mafic metavolcanic rocks into the selcuk formation

the glacial geomorphology and pleistocene history of south america between 38 s and 56 s abstract this paper presents new mapping of the glacial geomorphology of southern south america between latitudes 38 s and 56 s approximately the area covered by the former patagonian ice sheets glacial geomorphological features including glacial lineations moraines meltwater channels trimlines sandur and cirques were mapped from remotely sensed images landsat 7 etm pan sharpened landsat 7 and aster the landform record indicates that the patagonian ice sheets consisted of 66 main outlet glaciers together with numerous local cirque glaciers and independent ice domes in the surrounding mountains in the northern part of the mapped area in the chilean lake district 38 42 s large piedmont glaciers developed on the western side of the andes and the maximum positions of these outlet glaciers are in general marked by arcuate terminal moraines to the east of the andes between 38 s and 42 s outlet glaciers were more restricted in extent and formed alpine style valley glaciers along the eastern flank of the andes south of 45 s a series of large fast flowing outlet glaciers drained the ice sheet the location of these outlet glaciers was topographically controlled and there was limited scope for interactions between individual lobes west of the andes at this latitude there is geomorphological evidence for an independent ice cap close to sea level on the taitao peninsula the age of this ice cap is unclear but it may represent evidence of glacier growth during the antarctic cold reversal and or younger dryas chronozone maximum glacier positions are difficult to determine along much of the western side of the andes south of 42 s because of the limited land there and it is assumed that most of these glaciers had marine termini in the south east of the mapped area in the fuegan andes cordillera darwin the landform record provides evidence of ice sheet initiation by adding published dates for glacier advances from the literature we present maps of pre last glacial maximum lgm glacier extent lgm extent and the positions of other large mapped moraines younger than lgm in age a number of large moraines occur within the known lgm limits the age of these moraines is unknown but since many of them lie well outside the established maximum neoglacial positions the possibility that they reflect a return to glacial climates during the younger dryas chronozone or antarctic cold reversal cannot be discounted

cosmogenic nuclide exposure ages for moraines in the lago san martin valley argentina at several times during the quaternary a major eastward flowing outlet glacier of the former patagonian ice sheet occupied the lago san martin valley in argentina 49 s 72 w we present a glacial chronology for the valley based on geomorphological mapping and cosmogenic nuclide 10be exposure ages n 10 of boulders on moraines and lake shorelines there are five prominent moraine belts in the lago san martin valley associated with extensive sandar glaciofluvial outwash plains and former lake shorelines cosmogenic nuclide exposure ages for boulders on these moraines indicate that they formed at 14 3 1 7 ka 22 4 2 3 ka 34 4 3 4 ka to 37 6 3 4 ka and possibly 60 3 5 ka and 99 11 ka 1 these dated glacier advances differ from published chronologies from the lago san martin valley based on 14c age determinations from organic sediments and molluscs in meltwater channels directly in front of moraines or in kettleholes within end moraine ridges the moraine boulder ages also point to possible pre lgm glacial advances during the last glacial cycle and a key observation from our data is that the lgm glaciers were probably less extensive in the lago san martin valley than previously thought

formation of glaciolacustrine late pleistocene end moraines in the tasman valley new zealand abstract detailed examination of the tekapo formation in the tasman valley new zealand has identified 20 facies and five facies associations these associations are delta foresets and bottomsets sediment density flows ice contact lake sediments with ice rafted debris and resedimentation deposits and outwash gravels interpretation of the sediment landform associations informed by observations at modern glacier termini suggests that the late pleistocene tekapo formation moraines have been formed by downwasting of a more expanded tasman glacier during the early stages of glacier retreat ponds on the glacier surface develop into thermokarst lakes which enlarge and coalesce to form a large supraglacial lake continued downwasting causes the lake outlet river to entrench into the impounding latero frontal ice cored moraine lowering the lake level this exposes lake bottom sediments and forms shorelines on the proximal slopes of the ice cored moraine as the ice cored moraine melts these lake sediments are deformed and deposited against the mt john moraine the observations and interpretations reported here suggest the late pleistocene end moraine is a constructional feature not a structural glaciotectonic feature as suggested by previous studies

the timing and cause of glacial advances in the southern mid latitudes during the last glacial cycle based on a synthesis of exposure ages from patagonia and new zealand abstract glacier advances in the southern mid latitudes during the last glacial cycle ca 110 10 ka were controlled by changes in temperature and precipitation linked to several important ocean climate systems as such the timing of glacial advance and retreat can yield important insights into the mechanisms of southern hemisphere climate change this is particularly important given that several recent studies have demonstrated significant glacial advances prior to the global last glacial maximum glgm in patagonia and new zealand the cause of which are uncertain the recent increase in chronological studies in these regions offers the opportunity to compare regional trends in glacial activity here we compile the first consistent 10be exposure dating chronologies for patagonia and new zealand to highlight the broad pattern of mid latitude glacial activity over the last glacial cycle our results show that advances or still stands culminated at 26 27 ka 18 19 ka and 13 14 ka in both patagonia and new zealand and were broadly synchronous but with an offset between regions of up to 900 years that cannot be explained by age calculation or physically plausible erosion differences furthermore there is evidence in both regions for glacial advances culminating from at least 45 ka during the latter half of marine isotope stage mis 3 glacial activity prior to the glgm differed from the large northern hemisphere ice sheets likely due to favourable southern hemisphere conditions during late mis 3 summer insolation reached a minimum seasonality was reduced winter duration was increasing and sea ice had expanded significantly inducing stratification of the ocean and triggering northward migration of oceanic fronts and the southern westerly winds glacial advances in patagonia and new zealand during the glgm were probably primed by underlying orbital parameters however the precise timing is likely to have been intrinsically linked to migration of the coupled ocean atmosphere system which may account for the small offset between patagonia and new zealand due to differences in oceanic frontal migration during deglaciation advances or still stands occurred in both regions during the southern antarctic cold reversal ca 14 5 12 9 ka rather than the northern younger dryas ca 12 9 11 7 ka our findings suggest that major rearrangements of the southern hemisphere climate system occurred at various times during the last glacial cycle with associated impacts on the position and intensity of the southern westerly winds and oceanic fronts as well as wind driven upwelling and degassing of the deep southern ocean thus reconstructing the timing of glacial advance retreat using our compilation is a powerful way to understand the mechanisms of past interhemispheric climate change

paleogeographic and paleoenvironmental variations in the area of the pueyrredon posadas and salitroso lakes santa cruz province argentina during the holocene and its relationship with occupational dynamics abstract this work constitutes an integration of geological archaeological and palynological data from santa cruz province argentina for assessing the influence of paleogeographic and paleoclimatic changes in relation to the dynamics of human occupation during the holocene in order to carry out its objectives we surveyed different archaeological sites we collected pollen samples from two archaeological sites and described sampled and dated stratigraphic profiles of lake levels a digital elevation model was also developed to reconstruct old flooded areas given the obtained results we observe the influence that paleogeographic changes could have had on human occupational dynamics these changes may have opened up new areas for both settlement and mobility pollen records suggest a vegetation change from grass steppe to shrub steppe during the middle holocene most likely related to climate changes identified at a regional scale

a major advance of tropical andean glaciers during the antarctic cold reversal a moraine chronology determined by surface exposure dating shows that glaciers in the northern tropical andes expanded to a larger extent during the antarctic cold reversal 14 500 to 12 900 years ago than during the younger dryas stadial 12 800 to 11 500 years ago contrary to previous studies as a result previous chronologies and climate interpretations from tropical glaciers may need to be revisited the younger dryas was a cold period immediately prior to the present warm interglacial period there is clear evidence that it occurred throughout much of the northern hemisphere but its global extent remains debatable prior work in the tropical andes suggested extensive glacial advances during the younger dryas vincent favier and colleagues present new cosmogenic dating of glacial deposits and a reassessment of existing datasets from other glaciated andean landscapes to show that instead maximal glacial advances took place in the preceding antarctic cold reversal rather than a major advance the younger dryas now appears to have been associated with modest glacial retreat the younger dryas stadial a cold event spanning 12 800 to 11 500 years ago during the last deglaciation is thought to coincide with the last major glacial re advance in the tropical andes1 this interpretation relies mainly on cosmic ray exposure dating of glacial deposits recent studies however have established new production rates2 3 4 for cosmogenic 10be and 3he which make it necessary to update all chronologies in this region1 5 6 7 8 9 10 11 12 13 14 15 and revise our understanding of cryospheric responses to climate variability here we present a new 10be moraine chronology in colombia showing that glaciers in the northern tropical andes expanded to a larger extent during the antarctic cold reversal 14 500 to 12 900 years ago than during the younger dryas on the basis of a homogenized chronology of all 10be and 3he moraine ages across the tropical andes we show that this behaviour was common to the northern and southern tropical andes transient simulations with a coupled global climate model suggest that the common glacier behaviour was the result of atlantic meridional overturning circulation variability superimposed on a deglacial increase in the atmospheric carbon dioxide concentration during the antarctic cold reversal glaciers advanced primarily in response to cold sea surface temperatures over much of the southern hemisphere during the younger dryas however northern tropical andes glaciers retreated owing to abrupt regional warming in response to reduced precipitation and land surface feedbacks triggered by a weakened atlantic meridional overturning circulation conversely glacier retreat during the younger dryas in the southern tropical andes occurred as a result of progressive warming probably influenced by an increase in atmospheric carbon dioxide considered with evidence from mid latitude andean glaciers16 our results argue for a common glacier response to cold conditions in the antarctic cold reversal exceeding that of the younger dryas

paleolacustrine records from late pleistocene holocene in the perito moreno national park argentinian patagonian andes abstract the reconstruction of glacial paleolake formation and evolution allows the understanding of glacier advance and retreat behavior for longer periods of time new datings obtained from paleolacustrine deposits in the argentinian patagonian andes northwestern region of santa cruz province reveal that glacial lakes formed before the last glacial maximum they being as old as 31 278 cal yr bp and evolved until 6900 cal yr bp the interpretation of stratigraphic profiles described in different sectors of the perito moreno national park pmnp allows reconstructing lacustrine glaciolacustrine glacial till and delta paleoenvironments in each sector organic rich sediments were also sampled to obtain four absolute ages through ams methodology thus the paleogeographic reconstructions proposed are based on paleobathymetries performed from digital elevation models datings and facies distribution of lacustrine deposits mainly composed of laminated silts with subordinated sands and muds based on these new data the paleogeography of this area is characterized by two lakes at 880 m a s l at 31 200 ca yr bp one directly related to modern belgrano lake while the other is probably related to the burmeister lake but more than 10 km toward the east as respect to its current position the paleogeography reconstruction shows between 11 731 cal yr bp and 10 819 cal yr bp the existence of a major paleolake at 900 920 m a s l which was connected to several modern lakes finally a decrease of the paleolake level between 900 and 890 m a s l was recorded at 6900 cal yr bp which produced two major lacustrine systems separated by moraine deposits

lake level changes in central patagonia argentina crossing environmental thresholds for lateglacial and holocene human occupation the role and extent of climate as a cause of the expansion and decline of human cultures is still debatable it is clear however that human environment interactions are enhanced and interplay more closely in climatically sensitive areas such as around hydrologically closed basins lago cardiel is located at 498 s in the very arid rain shadow east of the andes providing an exceptionally receptive system to changes in hydrological balance results of a geophysical survey combined with sedimentological and geochemical studies provide a continuous lateglacial holo cene record of substantial water level changes these variations combined with archaeological results from the catchment area offer a unique possibility to explore the pattern of peopling within this remote area of the globe and its possible relation to climate change human occupation in patagonia is well documented towards the andes throughout the entire holocene archaeological data from the lago cardiel basin however show an apparent lack of human activity during the first part of this period which coincides with well constrained high lake levels our results show an intriguing coincidence between low lake level and increasing human occupation suggesting that the lago cardiel basin has focused human use during intervals with relatively lower effective moisture such as during the late pleistocene but its evidence may have been submerged this interpretation is confirmed by archae ological remains from lago strobel another perennial lake with a comparable catchment located in the same climatic region and thus sharing the same climatic history as lago cardiel copyright 2009 john wiley sons ltd

late pleistocene palaeolakes in the andean and extra andean patagonia at mid latitudes of south america abstract late pleistocene palaeolakes on the eastern side of andes glacial lakes and in the patagonian steppe pluvial lakes along 41 s latitude were studied natural dams glaciers moraines that maintained a high water level in glacial palaeolakes were melted or cut by erosion during late pleistocene climate amelioration with the retreat of the glaciers from the andean valleys during prominent regional deglaciation outflow from the eastern side of andes to the pacific ocean was formed about 13 2 ka bp as a result the water level in glacial palaeolakes fell rapidly in stages these changes were often preceded by volcanic tectonic activity which is suggested to be the touch of butterfly releasing mass balance adjustment in the changing landscape the lacustrine tephra stratigraphic pattern from the andes comprising more than 50 horizons since the last glaciation is presented the correlation of palaeoenvironmental changes between the andes and the patagonian steppe is suggested on the basis of two dacite marker horizons the deglaciation event that led to development of the new hydrological system in the andean palaeolakeland formed several large but short lived palaeolakes in closed basins in the patagonian steppe probably due to melting of local ice and permafrost accumulated during glaciation on the surrounding mountains and elevated plains