Holocene Evolution Research Articles

Neogene-Quaternary response of the Novohradské hory Mts. (Czech Republic) fluvial systems to tectonics – Analyses of morphotectonics, stream-length index and structural geology

Based on comparison of morphotectonic analysis results with the SL index analysis, airborne geophysical measurements and field geological and structural data, possible Miocene to Holocene development of the landscape relief of Novohradské Mts. (southern Moldanubian Zone; Bohemian Massif) with a significant contribution of active faulting is interpreted.We suppose a polyphase reactivation of pre-existing faults under (a) the Miocene-Pliocene stress-field (regional ∼ NNW–SSE extension) as (oblique) normal faults trending ∼ SW–NE to ∼NW–SE were responsible for the subsidence of the Třeboň Basin and Kaplice Furrow and (b) the Pliocene to Holocene stress-field (Shmax = 146°) when horizontal in the ∼NNW–SSE direction with possible activity of the prevailing ∼ NNE-SSW trending faults as a sinistral strike-slips or weak reverse oblique-slip movement. The second set of subvertical ∼ WNW–ESE faults was predominantly reactivated in a dextral strike-slip regime or as gentle reverse oblique-slip faults. These Miocene to Holocene events reflect the coupling between the East-Alpine–Carpathian segment and its northern foreland, mainly due to northward motion of the African and the Arabian lithospheric plates.The core of the Novohradské hory Mts. experienced a significant uplift compared to the neighboring areas of the Kaplice Furrow and the Třeboň Basin. The most significant uplift has been found near Rychnov nad Malší, and on the tectonic border between the Kaplice Furrow and the Bukovský hřbet Ridge. This uplift took place during the late Pliocene and Pleistocene, after the sedimentation of lacustrine sediments in the Kaplice Furrow. Although the combination of GIS, morphotectonic and geophysical analyses with validation by field structural data does not provide the final proof of young tectonic activity, we conclude that there is strong indication of Neogene-Quaternary reactivation of several faults in the Novohradské Hory Mts. Based on similar morphological features, it can be supposed that many areas in the Alpine Foreland and Bohemian Massif underwent similar tectonic evolution during the Miocene to Holocene era.

Holocene evolution of parabolic dunes, White River Badlands, South Dakota, USA, revealed by high-resolution mapping

AbstractThe White River Badlands (WRB) of South Dakota record eolian activity spanning the late Pleistocene through the latest Holocene (21 ka to modern), reflecting the effects of the last glacial period and Holocene climate fluctuations (Holocene Thermal Maximum, Medieval Climate Anomaly, and Little Ice Age). The WRB dune fields are important paleoclimate indicators in an area of the Great Plains with few climate proxies. The goal of this study is to use 1 m/pixel-resolution digital elevation models from drone imagery to distinguish Early to Middle Holocene parabolic dunes from Late Holocene parabolic dunes. Results indicate that relative ages of dunes are distinguished by slope and roughness (terrain ruggedness index). Morphological differences are attributed to postdepositional wind erosion, soil formation, and mass wasting. Early to Middle Holocene and Late Holocene paleowind directions, 324°± 13.1° (N = 7) and 323° ± 3.0° (N = 19), respectively, are similar to the modern wind regime. Results suggest significant landscape resilience to wind erosion, which resulted in preservation of a mosaic of Early and Late Holocene parabolic dunes. Quantification of dune characteristics will help refine the chronology of eolian activity in the WRB, provide insight into drought-driven landscape evolution, and integrate WRB eolian activity in a regional paleoenvironmental context.

The Glaciated Slopes of the High Alpine Mountains: Holocene Evolution and Impacts of the Current Climate Crisis

The Glaciated Slopes of the High Alpine Mountains: Holocene Evolution and Impacts of the Current Climate Crisis

Late Glacial and Holocene evolution of the estuarine section of the Nida River

Based on the results of detailed geological-geomorphological studies, old maps from the past 200 years, and historical data, the paper is the first to present the structure of the valley floor in the estuary of the Nida River, an upland tributary of the Vistula, and discuss changes in the development and course of their channels. The aim of the study was to grasp the importance of local factors, both natural (palaeogeographical, lithological and tectonic) and anthropogenic, in the morphogenesis of this section, where a relatively small upland stream crossed in the medieval and modern periods by important overland and water routes of the Polish-Lithuanian Commonwealth flows into the Vistula River, which is ten times larger. The discussed section is not deltaic in character. The branching of the Nida into several simultaneously functioning outlet arms may have been caused by the blocking of outflow from the valley during floods and the drainage of the flood waters at the valley mouth in several directions, via channels both permanent and periodic. Changes in the numbers and locations of the Nida estuaries in recent centuries have both natural and anthropogenic causes. The interaction between the main stream and its many-times smaller tributary in the studied section has resulted in a complex mosaic of forms and cut-and-fills of both streams, but with the Vistula playing the dominant role. The cut-and-fills of the Vistula “enclose” the Nida alluvium inside its valley on the Winiary-Nowy Korczyn line, while the cut-and-fills of the Nida only occur in a very narrow strip under the edge of the terrace. The Nida followed abandoned channels of the Vistula on Holocene cut-and-fill IIA, flowing parallel to the Vistula for 9 km. The floor of the Nida Valley lacks Holocene mineral-organic and mineral sediments, characteristic of other upland tributaries from loess areas. The regulation of the Vistula in the mid-19th century and the Nida in the first half of the 20th century fixed the courses of the rivers, completely changing the sedi­mentation regime in the estuarine section of the Nida, where backflow and associated sedimentation of fine-grained deposits occurred.

Holocene evolution of coastal dunes in western France: Regional reconstruction from archaeological and historical data

Holocene evolution of coastal dunes in western France: Regional reconstruction from archaeological and historical data

Palaeoenvironmental evolution of the Badain Jaran Desert hinterland during the Early to Middle Holocene: A multi-proxy reconstruction on Taoerlegetu paleolake, northwest China

In this paper, we examine the Early to Middle Holocene evolution of a prominent group of ground-water fed lakes in the southeastern hinterland of the Badain Jaran Desert (BJD) of northwest China. Specifically, we describe a sediment profile record from the Taoerlegetu (TR) palaeolake basin using multiple proxies of total organic carbon (TOC), total nitrogen (TN), C/N ratio, δ13Corg, grain size and mineral composition based on a well-dated trench profile. As C/N values suggest that sedimentary organic matter mainly originated from aquatic plants, δ13Corg values can be used as a qualitative proxy for water level because aquatic plants in different biotopes (water depth) have different δ13C values. Our results show that from 10.9 to 9.1 cal kyr B.P., water level rose slowly, and aquatic macrophytes occupied the lake basin. From 9.1 to 5.5 cal kyr B.P., water level reached an even higher level and phytoplankton replaced macrophytes as the major contributor to organic matter. The humid episode of the lakes in the hinterland of the BJD in the early Holocene might be related to the increased groundwater supply from the northeast region of the Tibet Plateau. These findings are consistent with earlier studies of lacustrine and peat sediments found in periphery of the modern lake group, which indicate that their geographic extent may have been larger in the past. A relative drought period recorded in the studied succession from 8.5 to 8.0 cal kyr B.P. marks an interval of reduced ground-water transport from the Tibet Plateau. This interval probably corresponds to the “8.2 ka cold event” and provides evidence that this widespread climate episode influenced groundwater processes across inland Asia.

Hydroclimatic record from an Altiplano cushion peatland (24°S) indicates large-scale reorganisation of atmospheric circulation for the late Holocene.

The hydroclimate of South America is characterized by the South American summer monsoon (SASM), a tropical atmospheric circulation that induces a summer precipitation regime, and the Southern Hemisphere Westerlies (SHW), an extratropical atmospheric circulation that induces a winter precipitation regime. Stretched between these two systems is a NW-SE-oriented region dominated by descending air masses, resulting in the South American subtropical dry zone (SASDZ), also known as the arid diagonal. We investigated the Cerro Tuzgle cushion peatland (CTP) located on the Argentine Altiplano, north of the present-day SASDZ. Previous work revealed that the CTP was consistently in the SASM regime during the last 2900 cal yr BP. Here, we extend the CTP record to the middle Holocene covering the last 7200 cal yr BP to gain further knowledge of the Holocene development of the SASM and potential modulations of the SASDZ. The prominent feature of the entire record is a distinct and lasting transition centred around 3100 cal yr BP characterized by declining minerogenic content, increasing organic carbon content, rising stable carbon isotope values of organic matter and cellulose, and increasing stable oxygen isotope values of cellulose. We interpret this specific proxy pattern as a hydroclimatic transition towards less arid conditions at the CTP after 3100 cal yr BP. The transition corresponds with the end of the continuous Holocene strengthening of the SASM between 3500 cal yr BP and 3000 cal yr BP indicated by proxy records from north and east of the CTP. The CTP does not reflect this strengthening of the SASM and rather exhibits a threshold response indicating the effective establishment of the SASM summer precipitation regime at 24°S. This suggests that moisture supply during a more arid middle Holocene was provided by isotopically depleted precipitation, while moisture supply after the transition originated from isotopically enriched SASM summer precipitation. Concurrent hydroclimatic changes in the SHW winter precipitation regime south of the SASDZ are documented in a distinct lake level rise of Laguna Aculeo (33°50´S) around 3200 cal yr BP. These coinciding hydrological changes of the SASM and the SHW precipitation regimes indicate larger scale reorganisations of atmospheric circulation components, potentially connected to major modulations of the SASDZ. Thus, our CTP record sheds light on the middle to late Holocene development of the SASM at its southern limit and corroborates connections between the tropical and extratropical hydroclimate of South America.

A pollen record from Lake Shuang in the Altai Mountains and its significance for the Holocene evolution of Asian jet streams and the monsoon system

A pollen record from Lake Shuang in the Altai Mountains and its significance for the Holocene evolution of Asian jet streams and the monsoon system

A pollen record from Lake Shuang in the Altai Mountains and its significance for the Holocene evolution of Asian jet streams and the monsoon system

A pollen record from Lake Shuang in the Altai Mountains and its significance for the Holocene evolution of Asian jet streams and the monsoon system

The relevance of coastal sediment budgets to management of sandy wave-dominated shorelines, a case study of Twofold Bay, southeastern Australia

Coastal compartments provide a framework for considering sediment budgets by defining the boundaries between adjacent beaches or sections of coast with a common sediment source. Here we present Twofold Bay as an ideal field laboratory to test the coastal compartment management approach, and in particular, note the relevance of long-term coastal evolution to shorter term planning timescales. Twofold Bay on the New South Wales south coast, Australia, contains four main beaches (Aslings, Boydtown, Whale and Fisheries Beaches) and associated barrier systems. We present a range of existing geological and geomorphic information combined with new field data which demonstrate considerable variation in the Holocene evolution and sediment budget of these adjacent beaches. These data show three broad sediment types exist within Twofold Bay and its beach systems: Type 1 is a mature quartz-rich sand derived from the shelf. Type 2 is a fine carbonate-rich sand from local biogenic production, and Type 3 is a coarse-fine angular feldspathic sand sourced from the Towamba River which drains to Twofold Bay via the southern end of Whale Beach. Newly available high-resolution topography and bathymetry as well as sediment thickness maps, have enabled shoreface geometry and basement topography to be estimated seaward of each beach and reveal considerable variability between sites helping explain past shoreline behaviour. Several new optically stimulated luminescence (OSL) ages for Boydtown Beach, combined with existing ages, confirm two distinct phases of shoreline progradation, initially at 0.16 m/yr, and then over the past ∼1500 years, at 0.65 m/yr. The increase in progradation rate reflects sediment supply from the Towamba River via Whale Spit. While these two beaches have become interconnected, Aslings Beach and Fisheries Beach are dominated by sediment Type 1 and Type 2 respectively and have different evolutionary histories with Aslings Beach forming a stationary barrier while Fisheries has prograded at 0.15 m/yr over the past ∼4300 years according to a new set of OSL ages. The Holocene evolution of these four adjacent beaches has resulted from their differing sediment sources and budgets and is in accord with several available datasets of decadal shoreline changes. These results demonstrate that spatial variation in shoreline behaviour is driven by differences in sediment budget and that just as adjacent beaches have behaved differently in the past, so will they in the future. Understanding these drivers of shoreline change is imperative to effective coastal management and planning in the context of projected future sea-level rise and other anthropogenic pressures.

Holocene evolution of the shelf mud deposits in the north-western South China Sea

Marine mud deposits contain rich information on past interactions between riverine sediment fluxes and marine processes. Massive mud deposits attached to a major river from South China, the Pearl River, are distributed on the north-western shelf of the South China Sea. This study examines the evolution history using cores penetrating through Holocene strata and deciphers its response to the river system, sea-level change, monsoon variations, human activities, etc. Geochemical and sedimentological data constrained by robust radiocarbon data show the difference in the evolution of mud deposits in shallow waters and on the middle shelf. Muddy wedges in shallow waters along the coast have formed since 7 ka BP, when modern current systems were established during the middle Holocene sea-level highstand. However, wide-spread muddy deposits in the middle shelf initiated after 3 ka BP which are associated with enhanced sediment fluxes and strengthened winter monsoon. Human activities on recent millennia have play a significant role in influencing the mud deposition on the north-west shelf of the South China Sea, as evidenced by the enrichment of heavy metals in marine sediments.

Relative sea level and wave energy changes recorded in a micro-tidal barrier in southern Brazil

AbstractConstructional sedimentary history of coastal barriers can provide insights regarding meteorological and oceanographic processes, and relative sea-level changes. We investigated the Holocene evolution of a segment of the Rio Grande do Sul Coastal Plain in southernmost Brazil. Data were obtained from ground-penetrating radargrams, optically stimulated luminescence dating, altimetry measurements, Google Earth imagery, and aerial photographs. These data allowed a qualitative and quantitative analysis of the beach profiles recorded in the radargrams. From which eolian, backshore/foreshore, breaker bars, and upper and lower shoreface radar facies were identified. The beach-related radar facies are recorded in twenty-eight progradational sand units (sigmoidal bodies). These units record increments of relatively steady deposition bounded by erosional surfaces produced by anomalous, high-magnitude storm events taking place about every 250 years. The upper shoreface strata include two to three breaker bars. Several pieces of evidence (number of breaker bars, upper shoreface gradient and progradation rate) suggest an alternation between dissipative and intermediate stages of barrier morphodynamics and a decrease of wave energy from 2 ka onwards. The barrier prograded during the last 7.1 ka, and initially, barrier progradation occurred because of a normal regression during a relative sea-level rise followed by a stillstand. Later, barrier progradation took place as a forced regression driven by a relative sea-level fall.

Rock walls distribution and Holocene evolution in a mid-latitude mountain range (the Romanian Carpathians)

Rock walls in high mountain areas are the expression of long–term slopes response (103–105 years) to tectonics, weathering and denudation and a major source of sediment and hazard. Controls of mountain rock walls (RW) distribution and the response to post-glacial evolution are rarely discussed in the literature at the scale of mountain ranges. Using a database of 791 RW mapped in the Romanian Carpathians, we present their distribution and morphometry in respect to lithological classes, structural features and topography and relate their exposure to post–Younger Dryas (Holocene) rock slope failure chronology. Statistical analysis results show the high significance of structural and tectonic control on RW distribution, which prevails in sedimentary units where it imposed the predominance of West and North orientations and led to the formation of RW with dimensions up to a degree higher compared to other lithologies. Morphometric data indicate that metamorphic and igneous RW (linked to a great extent to glacial valleys and cirques headwalls) are usually restricted to the highest sectors of the mountain slopes, being characterized by reduced relative heights, asymmetrically distributed, common on the North-exposed slopes and extremely rare on the South. Based on 38 in-situ produced 10Be surface exposure ages obtained on meter-sized boulders from the Southern and Eastern Carpathians, we hypothesise that metamorphic and igneous RW in the formerly glaciated Carpathian valleys were significantly shaped during Early Holocene (before 9 ka) by rock slope failures events that followed the deglaciation of the highest cirques and by intense RW permafrost degradation, which also affected some of the highest sedimentary units. We associate the long–term imprints of frost weathering to the significant North/South RW and rock glaciers distribution asymmetry, also identified in other mid-latitude mountain sites with similar topographic constraints.

The vertical distribution of soil organic carbon and nitrogen in a permafrost‐affected wetland on the Qinghai–Tibet Plateau: Implications for Holocene development and environmental change

AbstractCurrently, we know little about accumulation of soil carbon and nitrogen in permafrost‐affected wetlands on the Qinghai–Tibet Plateau (QTP). In this study, we analyze the vertical distribution of concentrations, stocks, and apparent accumulation rates of soil organic carbon (SOC) and total nitrogen (TN) in a wetland underlain by ice‐rich permafrost in the Headwater Area of the Yellow River (HAYR) on the northeastern QTP in the context of Holocene environmental change. SOC and TN stocks at depths of 0–216 cm were 80.0 kg C m−2 and 6.7 kg N m−2, respectively. During the past 7.3 kyr, the general regional climate trend in the HAYR was cooling and drying, as indicated by the decline in chemical weathering in the soil profile. Overall, SOC and TN concentrations increased during this period. Meanwhile, an intense period of SOC and TN accumulation occurred at 1,110–720 yr BP, in contrast to much lower apparent accumulation rates of SOC and TN for the other periods during the past 7.3 kyr. This suggests that the accumulation of SOC and TN in permafrost‐affected wetlands was also affected by local environmental factors, such as soil material deposition rate, in addition to climatic controls as exerted mainly by temperature and precipitation. This study may help integrate relevant studies on plateau wetlands into global models and estimates to better simulate and predict interactions between the carbon cycle and climate changes on a global scale.

Holocene development of Brabrand Fjord, eastern Jylland, Denmark.

The Brabrand Sø area west of Aarhus in eastern Jylland, Denmark, was deglaciated about 18 000 to 17 000 years ago. Coring in the present-day lake area revealed Early Holocene stream deposits overlain by marine deposits. The area was transgressed by the sea at c. 8500 cal. years BP and a 12 km long, narrow fjord was formed. In the beginning, the fjord housed a species-poor marine or brackish-water fauna with molluscs Hydrobia sp. (mudsnail), Littorina littorea (winkle), Mytilus edulis (blue mussel) and Cerastoderma sp. (cockle). This phase was followed by a phase during which the fjord housed a species-rich fauna that included Ostrea edulis (European flat oyster) and Ruditapes decussatus (palourde clam). During this phase the salinity and summer water temperatures were higher than in present day Aarhus Bugt and we also see evidence for strong bottom currents. This phase was probably characterised by a fairly large tidal amplitude. Two radiocarbon ages of O. edulis shells of c. 6250 and 6700 cal. years BP indicate that such conditions peaked during the period of the Ertebølle culture. The high-salinity phase was followed by a phase with a more species-poor fauna, this phase was also characterised by a high sedimentation rate – a feature seen in other fjords in the region. We suggest that the shift could be due to a decrease in tidal amplitude. Brabrand Fjord was eventually transformed into a lake due to land uplift and closure of the connection to Aarhus Bugt due to longshore sediment transport but the timing of the transition from fjord to lake is still unknown.

Holocene evolution of a floodplain wetland in the dryland piedmont of central-west Argentina

Holocene evolution of a floodplain wetland in the dryland piedmont of central-west Argentina

Role of the geologic-geomorphic setting of the Río de la Plata estuary coastal landscape in controlling freshwater lenses shape and distribution

Sea level fluctuations during the Holocene led to the deposition of different sedimentary facies in the Argentinean littoral of the Río de la Plata estuary and the adjacent sea area. This work aims to analyze the role of the geologic – geomorphic setting related to the Holocene evolution of the coastal landscape of the Río de la Plata estuary in terms of its control over the shape and distribution of freshwater lenses for water supply. For this purpose, satellite image analysis, field surveys, Vertical Electrical Soundings (VES), and sediment tests from boreholes were carried out. In addition, water samples were taken for electrical conductivity (EC) measurement, and major ions and stable isotopes of the water molecule determination. The results show that the geological and geomorphological evolution of the Río de la Plata estuary gave rise to positive landforms composed of highly permeable sediments that favor rainwater infiltration, which is stored in the shape of lenses. EC measurements in groundwater below these landforms recorded low values indicative of freshwater with isotopic content similar to that of local – global rainfall. Furthermore, the VES study allowed the definition of the freshwater – saline water interface. The outcomes of this study show that a detailed and exhaustive analysis of the geological – geomorphic setting resulting from the Holocene evolution of coastal zones constitutes, along with hydrochemistry and geophysics, appropriate tools for the exploration of freshwater lenses in coastal areas.

Soils and landscapes of Marajó island, Brazilian Amazonia: Holocene evolution, geoarchaeology and climatic vulnerability

Soils and landscapes of Marajó island, Brazilian Amazonia: Holocene evolution, geoarchaeology and climatic vulnerability

Late Holocene development of Bubiyan Island, Kuwait

AbstractBubiyan Island, presently a vast sabkha and salt flat in the westernmost part of the Shatt Al-Arab delta, originated ca. 4000 cal yr BP as prodelta deposits from a paleochannel of the Euphrates River that flowed into a shallow sea. Southeastern Bubiyan Island first surfaced when spits and barrier islands formed on a 1–2 m forebulge caused by heavy sediment load to the northwest; the spits and barriers delineated an incipient shoreline and sheltered a shallow lagoon. Progradation of southeastern Bubiyan Island began when the spits and barriers were gradually stranded as beach ridges during minor sea-level fluctuations and continued marginal uplift. AMS dating of the beach ridges, which are ~1–5 km from the present shoreline, implies that Late Holocene relative sea level fell in three phases: ca. 3700–3400 cal yr BP, ca. 2600–1000 cal yr BP, and ca. 600–500 cal yr BP. Prior to each phase, relative sea level apparently stabilized to near stillstands, allowing spits and barriers to accrete. Torpedo-jar pottery sherds scattered on some of the most prominent beach ridges indicate Sasanian (AD ca. 300–650; 1650–1300 cal yr BP) to early Islamic (AD ca. 650–800; 1300–1150 cal yr BP) periods of human presence, concurrent with the Second phase of beach-ridge formation.

Ground‐penetrating radar (GPR) investigations of a large‐scale buried ice‐marginal landsystem, Skeiðarársandur, SE Iceland

The sedimentary record of Icelandic ice‐contact environments provides critical insights into past glacier margin dynamics and position, relative sea level, and the geomorphic processes that drive the evolution of proglacial environments. This important archive has been little exploited, however, with most glacier and sea‐level reconstructions based on limited sedimentary exposures, coring and surface geomorphic evidence. We report an extensive (42 km of data within a 24‐km2 study area) and deep (reflections recorded at depths up to 100 m) low‐frequency (40 and 100 MHz) ground‐penetrating radar (GPR) survey of the Sandgígur moraines, SE Iceland. GPR profiles reveal a much larger (67 m high) and extensive (1.25 km wide) buried moraine ridge than that suggested by surface topography (typically 125 m wide and 7 m high). These data reveal that the Sandgígur moraines was deposited during a major Holocene re‐advance of Skeiðarárjökull. The moraine ridge is buried by sediments dominated by glacifluvial deposits with an estimated sediment volume of 1.04 km3. We combine GPR‐derived subsurface architecture and the surface morphology to develop a conceptual model detailing the geomorphic evolution of the moraine and surrounding region. These results provide new insights into the Holocene evolution of Skeiðarársandur, identifying the presence of a former major ice‐margin position, as well as a past relative sea‐level limit. Furthermore, we establish that sediment supply and available terrestrial accommodation space are dominant drivers in the formation and evolution of vast sandar environments.