New evidence for the presence of reindeer (Rangifer tarandus) on the Iberian Peninsula in the Pleistocene: an archaeopalaeontological and chronological reassessment

Reindeer (Rangifer tarandus) populations reached the Iberian Peninsula during the end of the Middle Pleistocene and there are numerous examples of this species from Late Pleistocene Mousterian and Upper Palaeolithic sites. In this paper, new evidence of reindeer in the east Cantabrian region is presented that further supports the timing of this species’ first appearance, and previous assessments are updated. To date, the presence of this species has been identified at 55 sites in the Iberian Peninsula, nearly as many as those of mammoth (Mammuthus primigenius) and woolly rhinoceros (Coelodonta antiquitatis) combined. Most of the sites with presence of reindeer (50) are located in the Cantabrian region with a clear increase in the density of sites and remains towards the Pyrenees. The remaining five sites with evidence of reindeer are located on the other side of the Pyrenees in the NW corner of Catalonia. In contrast, archaeological evidence of reindeer in the form of art (both parietal and portable) is more scarce and scattered. Evidence for the representation of these animals has been found outside the northern fringe of the Iberian Peninsula, which could reflect either long‐distance cultural communication or the movement of human groups.     

History of the reindeer (Rangifer tarandus) in the eastern Baltic region and its implications for the origin and immigration routes of the recent northern European wild reindeer populations

A total of 45 subfossil reindeer (Rangifer tarandus) antlers and bones - artefacts excluded - have been found over the years in the Baltic countries of Estonia, Latvia and Lithuania. The relatively high number of specimens suggests a stable residence of the species in the eastern Baltic region. For the first time, 12 of these finds were radiocarbon-dated. The ages of the samples range between 12 085 and 9970 ¹⁴C yr BP (14 180-11 280 cal. yr BP), and cover the Lateglacial and early Holocene, a time period during which climatic conditions shifted from periglacial to temperate. The dates suggest a rapid colonization of the area during the deglaciation period and a local extinction around the Pleistocene-Holocene boundary. The results of the study do not support the theory that the recent wild reindeer populations of northern Europe had their origin in the Late Weichselian reindeer populations of the eastern Baltic region.     

Neighborhood covenants and restrictions: an examination of fit

Covenants and restrictions (C&Rs) have increased in popularity in recent decades, being commonly applied in new residential developments. Despite the fact that developers are more commonly writing C&Rs for their developments, little research has investigated how well C&Rs actually fit the preferences of residents. Recognizing this gap in the literature, this paper examines the fit of neighborhood C&Rs with resident preferences in Porter County, Indiana, a growing suburban/exurban place in the Chicago Metropolitan Statistical Area. The researcher conducted in-depth interviews with 51 residents to ascertain how well C&Rs fit resident preferences. The majority of interviewees stated that C&Rs match resident preferences because they believed that C&Rs promoted subdivision tidiness and worked to support property values. The minority view was that C&Rs do not fit because they are too strict and residents do not obey C&Rs. Interviewees who perceived a fit were more likely to have a lower level of engagement with C&Rs and were more likely to live in developments with no C&R enforcement attempts by the homeowners’ association (HOA). The results suggest the particular content of C&Rs does not seem to fit resident preference; rather the fact that C&Rs are not enforced fits resident preference. Seemingly, residents are content being unaware of the C&Rs, then they do not know if someone is breaking the rules or not. This may imply that residents would not want to have C&Rs in the first place.     

Late and middle Pleistocene ungulates dietary diversity in Western Europe indicate variations of Neanderthal paleoenvironments through time and space

Mesowear and microwear on enamel from 763 teeth of middle and late Pleistocene ungulates were analysed to infer the potential of dental wear analysis of faunal remains as a paleoenvironmental and paleoclimatic proxy in relation to climatic changes and diversity of vegetation available in the environment. Fossil localities including levels belonging to two glacial and two interglacial stages were selected in Germany, France, and Spain. At a temporal scale, results indicate that the dietary diversity in ungulates is higher during interglacial phases (MIS 5 and 3) than during pleniglacial phases (MIS 8 and 4). Dietary diversity is concluded to be related to climate-driven vegetation changes which during interglacials lead to increased variety of potential food items available to ungulates. At the geographical scale, during interglacials, changes in diet composition are evident along geographical gradients. The corresponding dietary gradients are proposed to be related to climate and vegetation gradients reflecting more arid climates in the Mediterranean area compared to North-Western Europe. Species consistently represented at all localities investigated are Cervus elaphus (Cervidae, Artiodactyla) and Equus ferus (Equidae, Perissodactyla). C. elaphus populations are found to consistently have less abrasive diets than E. ferus populations but dietary traits of both species varied largely, revealing a significant plasticity in the feeding adaptation of both species. Those traits are concluded to be related to differences in vegetation structure at each locality and complement the evidence that ungulates have broader dietary habits than what is usually assumed.     

Generalism as a subsistence strategy: advantages and limitations of the highly flexible feeding traits of Pleistocene Stephanorhinus hundsheimensis (Rhinocerotidae,Mammalia)

The so-called Hundsheim rhinoceros, Stephanorhinus hundsheimensis, was a very common faunal element of the Early to early Middle Pleistocene period in the western Palaearctic. In this study, individuals from two different central European populations of the Hundsheim rhinoceros were analysed in order to determine whether their local dietary signals could reflect differing food availability between the two populations, and whether such information could provide a better understanding of the ecological role of S. hundsheimensis within corresponding faunal assemblages, and of its principal subsistence strategy in the western Palaearctic. The mesowear traits observed in the studied S. hundsheimensis populations have been interpreted as representing biome-specific signals, indicating grassland vegetation at the site of Süßenborn, and dense to open forests at Voigtstedt (both localities in Germany). The analyses performed on the fossil rhino material demonstrate the most pronounced dietary variability ever established for a single herbivorous ungulate species by mesowear studies. This variability ranges from an attrition dominated grazing regime, to a one of predominantly browsing, and characterises S. hundsheimensis as the most ecologically tolerant rhinoceros of the Palaearctic Plio-Pleistocene. Although such dietary flexibility proved an effective enough subsistence strategy over a period of 600–900 ka (1.4/1.2–0.6/0.5 Myr) in the western Palaearctic, the situation changed dramatically after 0.6 Myr BP, when the new species of rhinoceroses, Stephanorhinus hemitoechus and Stephanorhinus kirchbergensis, appeared and started to compete for both the grass and the browse. For the generalist S. hundsheimensis, this bilateral interference was detrimental to its success in all of its habitats. The successful competition of specialised forms of rhinoceroses, which might have originated as a result of the development of 100 ka periodicity in the global climatic record, is proposed as the main reason for the extinction of S. hundsheimensis during the early Middle Pleistocene.     

The Piànico tephra: an early Middle Pleistocene record of intraplate volcanism in the Mediterranean

ABSTRACT Distal tephra are a valuable record of the volcano-tectonic evolution of an area under study. Here, we document the case of the Early Middle Pleistocene rhyolitic tephra of Piànico, discovered in the Southern Italian Alps. The geochemical characteristics of Piànico are unique among the distal tephra outcropping in Italy and indicate an intraplate volcanism at the source. The alkali composition and trace elements show a striking resemblance with the rhyolitic complex of the Euganean Hills, located 170 km from Piànico. However, these rhyolites are much older (Oligocene). Alternatively, the source of this intraplate volcanic episode could be located in the southern Tyrrhenian Sea.     

Stratigraphic potential of amino acid ratios in Pleistocene terrestrial gastropods: an example from West-Central Indiana, USA

Miller, Barry B., McCoy, William D. & Bleuer, Ned K. 1987 06 01: Stratigraphic potential of amino acid ratios in Pleistocene terrestrial gastropods: an example frpm West-Central Indiana, USA. Boreas , Vol. 16, pp. 133–138. Oslo. ISSN 0300–9483.
The terrestrial gastropods Catinella spp., Stenotrema leai and Hendersonia occulta have been studied from 10 Wisconsinan and pre-Wisconsinan sites in west-central Indiana to determine if amino acid racemization values from these fossils would have stratigraphic utility in this area. The ages of the samples range from about 20,000 years B.P. for materials collected from radiocarbon-dated deposits of the Trafalgar Formation, to >730,000 years B.P. for fossils obtained from magnetically reversed silts of the Jessup and Banner Formations. The shell samples have yielded four groups or aminozones based on the ratio of D-alloisoleucine to L-isoleucine in both the free fraction and the total acid hydrolysate from the shell samples. The results of this preliminary study appear to be consistent with the previously assumed age of the strata from which the fossils were collected and suggest that the technique has great promise as a chronostratigraphic tool in Quaternary sequences that contain terrestrial pulmonate and prosobranch gastropods.     

Modeling geothermal regime in the Qinghai-Tibet Plateau: an examination of the upper-boundary condition

This study describes to which degree the numerical prediction of ground temperatures in the Qinghai-Tibet Plateau is influenced by the upper-boundary adoptions. A temperature-controlled upper boundary and a heat-flux upper boundary (HFUB) are, respectively, applied to model the ground temperatures at a typical section on the plateau. Predicted temperatures are compared to the field-observed temperature profile at this test section, in order to distinguish the predicted deviations. Comparison of these deviations confirms that a HFUB model promises better prediction accuracy, especially in the modeling ground-temperature zero-curtain effect. Adoption of a HFUB, however, requires examining whether the specified initial ground temperature is in its thermal equilibrium state. Special emphasis is paid on how to use a HFUB to simulate the temperature under a pavement in the plateau and on the pro and con regarding the uses of different upper-boundary models.     

Late Pleistocene morainal bank facies at Greystones, eastern Ireland: an example of sedimentation during ice marginal re-equilibration in an isostatically depressed basin

A late Pleistocene morainal bank is sited in a depocentre to the lee of a major rock ridge, near Greystones, in the western Irish Sea Basin. During deglaciation the ridge provided a pinning point during tidewater wastage northwards. Sedimentation patterns and palaeocurrent data show morainal bank growth by discharge from a single basal efflux located to the east or south-east of the ridge during ice marginal re-equilibration. The four lithofacies associations which are recognized from the western part of the formerly more extensive apron are related largely to variable jet and plume sedimentation. At the base of the 1.6 km long exposure, Lithofacies association 1 (massive mud, muddy diamict and laminated mud) was deposited from turbid plumes, variable ice rafting and traction current activity. Lenticular units of gravels within this mud bank record high energy pulses and sediment fluxes from the efflux jet. Lithofacies association 2 (sands, laminated muds and muddy diamict) is discontinuous and occurs within basins along a marked erosion surface cut in Lithofacies association 1. It is associated with a decrease in jet strength, traction currents and suspension sedimentation. Lithofacies association 3 is a tabular body of interbedded diamicts and gravels which is present along the entire section. It documents the decay phase of re-equilibration as the ice margin disintegrated catastrophically and released large volumes of heterogeneous sediment which was resedimented by quasicontinuous mass flow. Lithofacies association 4 consists of stratified and massive gravels within distributary channels cut into underlying facies and represents the last phase of meltwater activity. Sediment geometries, particularly sedimentary contrasts representing erosion surfaces at a variety of scales and abrupt textural contrasts are attributed to jet switching. Lithofacies association 1 (60%) and Lithofacies association 3 (30%) are the dominant facies. In favourable topographic settings this stratigraphic couplet is a signature for re-equilibrated ice margins in isostatically depressed basins dominated by tidewater fronts, rapid ice flux and high relative sea level. Morainal banks document rapid environmental change and in the Irish Sea Basin they form part of a deglacial event stratigraphy related to unstable tidewater margins and high relative sea level. Deglaciation was therefore controlled primarily by high relative sea level rather than climatic forcing. Facies variations should therefore not be used for stratigraphic correlations in place of direct stratigraphy. This type of situation may be more common than hitherto realized in Late Pleistocene, mid-latitude shelves where most of the preserved stratigraphy is characterized by complex, interbedded sequences formed when isostatic depression exceeded sea-level fall.     

A geological record of multiple Pleistocene tsunami inundations in an oceanic island: The case of Maio,Cape Verde

In the Central Atlantic archipelagos – the Canaries, Cape Verde, Madeira and the Azores – tsunami hazard is often regarded as low, when compared with other extreme wave events such as hurricanes and storms. The geological record of many of these islands, however, suggests that tsunami hazard may be underestimated, notwithstanding being lower than in areas adjacent to subduction zones, such as the margins of the Pacific and Indian oceans. Moreover, tsunamis in oceanic islands are generally triggered by local large-scale volcanic flank collapses, for which little is known about their frequency, making it difficult to estimate the probability of a new occurrence. Part of the problem lies in the fact that tsunami deposits are usually difficult to date, and few islands in the world exhibit evidence for repeated tsunami inundation on a protracted timescale. This study reports on the presence of abundant tsunami deposits (conglomerates and sandstones) on Maio Island (Cape Verde) and discusses their stratigraphy, sedimentological characteristics, probable age and tsunamigenic source. Observations indicate that four distinct inundation events of variable magnitude took place during the Pleistocene. One of the tsunami deposits yielded a high-confidence U/Th age of 78·8 ± 0·9 ka, which overlaps within error with the 73 ± 7 ka age proposed for Fogo volcano's flank collapse, an event known to have had a significant tsunami impact on nearby Santiago Island. This shows that the Fogo tsunami also impacted Maio, resulting in runups in excess of 60 m above coeval sea-level at ca 120 km from the source. Two older deposits, possibly linked to recurrent flank collapses of the Tope de Coroa volcano in Santo Antão Island, yielded lower-confidence ages of 479 to 390 ka and 360 to 304 ka. A younger deposit (<78 ka) remains undated. In summary, the geological record of Maio exhibits well-preserved evidence of repeated tsunami inundation, reinforcing the notion that tsunami hazard is not so low at volcanic archipelagos featuring prominent and highly-active volcanoes such as in Cape Verde.     

Distribution and chronology of Pleistocene permafrost features in France: Database and first results

Numerous periglacial features (polygons, nets, soil stripes, ice‐wedge pseudomorphs and sand‐wedge casts, involutions) have been recorded in France by examining bibliographical sources and aerial photographs. These data show that a large part of France was affected by permafrost during the Pleistocene and only the southern Aquitaine Basin and Languedoc seem to have been beyond its maximum extent. The first OSL ages obtained from the aeolian infill of wedge structures indicate that at least two phases of thermal contraction cracking occurred in southwestern France between ～25 and 36 ka. Chronostratigraphical data from loess in northern France indicate that these episodes correspond to the formation of ice‐wedge networks associated with tundra gleys. In the latter region, two additional permafrost episodes probably occurred during the Last Glacial, the older one corresponding to the end of Marine Isotope Stage (MIS) 4 around 60 ka and the more recent one to MIS 2 around 19–16 ka. Although stratigraphical data indicate that these episodes were relatively short (about one millennium), relict permafrost may have existed for longer periods in northern France.     

Pleistocene speleothems of Mallorca: implications for palaeoclimate and carbonate diagenesis in mixing zones

The Pleistocene speleothems of Sa Bassa Blanca cave, Mallorca, are excellent indicators of palaeoclimate variations, and are samples that allow evaluation of the products and processes of mixing‐zone diagenesis in an open‐water cave system. Integrated stratigraphic, petrographic and geochemical data from a horizontal core of speleothem identified two main origins for speleothem precipitates: meteoric‐marine mixing zone and meteoric‐vadose zone. Mixing‐zone precipitates formed at and just below the water–air interface of cave pools during interglacial times, when the cave was flooded as a result of highstand sea‐level. Mixing‐zone precipitates include bladed and dendritic high‐Mg calcite, microporous‐bladed calcite with variable Mg content, and acicular aragonite; their presence suggests that calcium‐carbonate cementation is significant in the studied mixing‐zone system. Fluid inclusion salinities, δ¹³C and δ¹⁸O compositions of the mixing‐zone precipitates suggest that mixing ratio was not the primary control on whether precipitation or dissolution occurred, rather, the proximity to the water table and degassing of CO₂ at the interface, were the major controls on precipitation. Thus, simple two‐end‐member mixing models may apply only in mixing zones well below the water table. Meteoric‐vadose speleothems include calcite and high‐Mg calcite with columnar and bladed morphologies. Vadose speleothems precipitated during glacial stages when sea level was lower than present. Progressive increase in δ¹³C and δ¹⁸O of the vadose speleothems resulted from cooling temperatures and more positive seawater δ¹⁸O associated with glacial buildup. Such covariation could be considered as a valid alternative to models predicting invariant δ¹⁸O and highly variable δ¹³C in meteoric calcite. Glacio‐eustatic oscillations of sea‐level are recorded as alternating vadose and mixing‐zone speleothems. Short‐term climatic variations are recorded as alternating aragonite and calcite speleothems precipitated in the mixing zone. Fluid‐inclusion and stable‐isotope data suggest that aragonite, as opposed to calcite, precipitated during times of reduced meteoric recharge.     

Analysis of Pleistocene Cryogenic and Tectonic Processes in Northwestern Siberia: A Cryoheterotopic Approach

Doklady Earth Sciences - Results characterizing the Pleistocene environments in the region of Northwestern Siberia are presented. The study of these environments is carried out from the perspective...     

Aeolian activity in northern Amazonia: optical dating of Late Pleistocene and Holocene palaeodunes

Palaeodunes were examined on the eastern margin of the Rio Branco–Rupununi savanna, northeast Amazonia. Optical dating suggests that the onset of aeolian activity was between 17 000 and 15 000 yr ago, just after the Last Glacial Maximum. Both the palaeodune axes and modern dominant wind directions have northeast to east‐northeast directions, implying no significant shift in atmospheric circulation patterns over northeast Amazonia during the Late Pleistocene to Holocene. Major regional climate change events, such as the Younger Dryas, do not appear to have had any effect on the rates of aeolian deposition at the study site. Aeolian activity appears to have continued to the present day, showing a remarkably constant deposition rate of around 0.13 m kyr^?1 initially, increasing smoothly to the present. Until more palaeodunes in northern Amazonia are dated, it is impossible to determine if this record of gradual aeolian deposition is a reliable regional palaeoclimate indicator, rather than being the result of local bioclimatic and geomorphological effects. Copyright © 2004 John Wiley & Sons, Ltd.     

The past in dust: current trends and future directions in Pleistocene geoarcheology of European loess

Loess is a main archive of Pleistocene landscapes and environments and therefore has an important connection to the preservation and interpretation of Paleolithic sites. In Europe, anthropogenic sites have been found in loess because of past local occupation. At one extreme, sites are well preserved with minimal disturbance often accompanied by embedded proxies to estimate ecological parameters. On the other hand, loess deposits have undergone post-depositional alterations such as weathering, pedogenesis or bioturbation due to changing environmental conditions or other disturbances that obscure anthropogenic sites. We outline the current state of research and connections between Paleolithic archeology and loess research while introducing a series of subsequent regional case studies as part of a special issue. We also make recommendations for future work to incorporate a wider variety of methods to create more robust inferences on hominin and environmental evolution and their connections.     

Development of an incised valley‐fill at an evolving rift margin: Pleistocene eustasy and tectonics on the southern side of the Gulf of Corinth,Greece

This study from the southern margin of the Gulf of Corinth documents a Late Pleistocene incised valley‐fill succession that differs from the existing facies models, because it comprises gravelly shoal‐water and Gilbert‐type deltaic deposits, shows strong wave influence and lacks evidence of tidal activity. The valley‐fill is at least 140 m thick, formed in 50 to 100 ka between the interglacials Marine Isotope Stage 9a and Marine Isotope Stage 7c. The relative sea‐level rise left its record both inside and outside the incised valley, and the age of the valley‐fill is estimated from a U/Th date of coral‐bearing deposits directly outside the palaeovalley outlet. Tectonic up‐warping due to formation of a valley‐parallel structural relay ramp contributed to the valley segmentation and limited the landward extent of marine invasions. The valley segment upstream of the ramp crest was filled with a gravelly alluvium, whereas the downstream segment accumulated fluvio‐deltaic deposits. The consecutive deltaic systems nucleated in the ramp‐crest zone, forming a bathymetric gradient that promoted the ultimate growth of thick Gilbert‐type delta. The case study contributes to the spectrum of conceptual models for incised valley‐fill architecture. Four key models are discussed with reference to the rates of sediment supply and accommodation development, and it is pointed out that not only similarity, but also all departures of particular field cases from these end‐member models may provide valuable information on the system formative conditions. The Akrata incised valley‐fill represents conditions of high sediment supply and a rapid, but stepwise development of accommodation that resulted from the spatiotemporal evolution of normal faulting at the rift margin and overprinted glacioeustatic signals. This study adds to an understanding of valley‐fill architecture and provides new insights into the Pleistocene tectonics and palaeogeography of the Corinth Rift margin.     

Quantitative parameters of Pleistocene pelagic sedimentation in the World Ocean: Global trends and regional features

A comparative analysis of Pleistocene pelagic sedimentation in the Pacific, Indian, and Atlantic oceans revealed the predominance of terrigenous sediments, while carbonate and siliceous sediments are second and third in abundance. During Pleistocene, the mass of terrigenous and siliceous sediments increased, while that of carbonates slightly decreased. The latter is related to the fact that the bottom waters aggressive to carbonates became increasingly generated at high latitudes, thus exceeding an increase in the productivity of plankton carbonate organisms. The peculiarities of accumulation of the main types of bottom sediments in the Pleistocene are considered. It is concluded that the Pleistocene geological history of continents, especially neotectonic uplift and continental glaciations, played an important role in pelagic sedimentation.     

Softening,localization and stabilization: capture of discontinuous solutions in J2 plasticity

This paper exploits the concept of stabilization techniques to improve the behaviour of mixed linear/linear simplicial elements (triangles and tetrahedra) in incompressible or nearly incompressible situations. Elasto-J2-plastic constitutive behaviour has been considered with linear and exponential softening. Two different stabilization methods are used to attain global stability of the corresponding discrete finite element formulation. Implementation and computational aspects are also discussed, showing that a robust application of the proposed formulation is feasible. Numerical examples show that the formulation derived is free of volumetric locking and spurious oscillations of the pressure. The results obtained do not suffer from spurious mesh-size or mesh-bias dependence, comparing very favourably with those obtained with the standard, non-stabilized, approaches. Copyright © 2004 John Wiley & Sons, Ltd.     

西藏纳木错和藏北高原古大湖晚更新世以来的湖泊演化与气候变迁

根据野外水准测量与室内实验分析，本文探讨了西藏纳木错和藏北高原古大湖晚更新世以来的湖泊演化和气候变迁。在纳木错沿岸拔湖48m以下，发育了6级湖岸阶地，拔湖48-139．2m发育有高位湖相沉积。研究表明，纳木错湖泊发育与藏北高原东南部古大湖演化可划分为3个阶段：①116-37ka B．P．间的古大湖期；②37-30ka B．P．间的外流湖期；③30kaB．P．以来的纳木错期。在古大湖阶段，包括纳木错、色林错和扎日南木错、当惹雍错等藏北高原东南部的一大批现代大、中、小型湖泊，都是互相连通的一个古大湖，其范围可能超过了现代的藏北内、外流(怒江)水系的分水岭。它或许还与藏北高原南部和西部的其他古湖相连，成为统一的藏北高原“古大湖”。通过对纳木错湖相沉积形成时代与深海氧同位素对比，易溶盐、pH值、地球化学、介形类和孢粉分析等的综合研究发现，湖相沉积记录了自晚更新世以来的湖泊演化和气候变迁信息。资料显示古大湖期湖面最高，气候温和清爽；外流湖期湖面急剧下降，气温和湿度较现今略高；纳木错期以来气候经历了全新世最宜期的暖湿后日益干旱化，气温波动，湖面持续下降。表明自晚更新世以来该区气候在逐渐变干的总趋势的基础上，经历了多次明显的冷暖与干湿波动。     

早更新世晚期松花江水系袭夺：地球化学和沉积学记录

水系演化重建是恢复区域构造历史及古环境变化的重要方法。松花江作为中国七大水系之一,其水系演化的相关研究目前还比较薄弱,尤其是第四纪松花江中- 上游是否存在流向反转尚无准确结论。沉积物是河流地质过程的直接产物,是水系演化研究的关键。为此,本研究对哈尔滨荒山钻孔岩芯(HS)进行了磁化率、古地磁和元素地球化学组成分析。结果表明,岩芯62. 3 m(0. 94 Ma B. P. )处,沉积物的岩性、磁化率及元素地球化学组成均发生显著变化。岩芯沉积物岩性在62. 3 m上下发生明显变化,是河流沉积两个沉积旋回的转折点。62. 3 m以下地层的磁化率极低,基本为0,且变化幅度极低,元素地球化学组成则急剧波动,并表现出与现在松花江哈尔滨段下游水系(岔林河、蚂蜒河和牡丹江)相近的地球化学组成;然而,62. 3 m以上地层的磁化率突然升高(99. 673×10-8 m3 kg-1),并具有周期性的高低变化。元素组成呈现稳定的小幅变化,并表现出与拉林河、嫩江和松花江吉林段相近的地球化学组成。0. 94 Ma B. P. 沉积物物源的变化表明河流流向发生了显著变化,松花江中上游河段流向曾在此时发生反转。地球化学记录的水系反转也得到了河流阶地地貌和沉积学证据(砾石的粒径和排列方向)的支持。早更新世早- 中期,以佳- 依分水岭为界,松花江中上游(肇源- 依兰河段)河流自东向西流入松嫩湖盆,松花江下游向东流经三江平原;早更新世晚期,受构造- 地貌- 气候耦合作用的影响,佳- 依分水岭持续抬升,而三江平原一侧不断下沉,佳- 依分水岭两侧河流发生溯源侵蚀,最终导致佳- 依分水岭在0. 94 Ma B. P. 被切穿,松花江中上游水系被下游水系所袭夺,河流流向发生反向,自西向东流经依佳峡谷进入三江平原,现代松花江水系逐渐建立。本研究有助于我们加深对松嫩平原水系演化的理解,为探索东亚水系演化的一致性和区域差异性提供研究证实,同时对松花江流域自然资源禀赋的调查乃至国土空间开发利用具有重要实践意义。