Paleosols,trace fossils,and precipitation estimates of the uppermost Triassic strata in northern New Mexico

This study provides a detailed pedogenic evaluation of two Upper Triassic (Late Norian through Rhaetian) stratigraphic intervals in New Mexico in order to assess the climate and ecology of the Latest Triassic, which ended in a mass extinction. The two study areas are located in north–central and east-central New Mexico and are separated by 200 km. Each section contains abundant paleosols of varying maturity with features that reflect an arid to semiarid climate. There is little pedogenic variation throughout the strata at each location, and a typical paleosol profile is about 1 m thick and has an AB–Bw–Bk–BC horizon succession. Bkm, Bss, Bssk, or Bssg horizons are present in some paleosols. Micromorphological features suggest dominantly well-drained sola (e.g., abundant carbonate nodules, illuviated clay) with minor periods of moist or saturated conditions (e.g., FeMn concretions, FeMn coatings and hypocoatings, sepic-plasmic fabrics). Trace fossils are abundant in these strata and are dominated by Taenidium serpentinum and root traces. Depth-to-carbonate functions estimate that mean annual precipitation was between 200 and 450 +/? 95 mm. Relative to location 1 (eastern New Mexico), location 2 (north–central New Mexico) produced higher paleo-precipitation estimates and has stronger and more abundant sepic-plasmic fabrics in thin sections. The presence of a gleyed paleosol, Camborygma eumnkenomos, and slickensides at location 2 also suggests conditions wetter than at location 1. Taxonomically, all of the paleosols in this study appear to be Entisols or Aridisols and can be grouped into seven representative pedotypes of varying maturity. By comparing these paleosols to modern soils, this study demonstrates that the Late Triassic Western Interior during the Late Norian to Rhaetian was arid to semiarid and supported a desert shrub environment that had localized and periodic moist or saturated soil conditions.     

Paleopedology and geochemistry of Late Mississippian (Chesterian) Pennington Formation paleosols at Pound Gap,Kentucky, USA: Implications for high-frequency climate variations

Climate during the Late Mississippian (late Chesterian) in the southern Appalachian Basin was characterized by alternating periods of aridity and humidity. Pennington Formation paleosols at Pound Gap record climate and ecological changes for latest Chesterian time, ending at the Mississippian–Pennsylvanian systemic boundary. Forty paleosols were identified, described, and assigned to seven pedotypes. Inferred soil orders considered as analogs include Histosols, Entisols, Inceptisols, Alfisols and Oxisols, but are dominated by Vertisols. Classification of an Oxisol was determined by field and geochemical evidence of intense leaching and kaolinite-dominated clay mineralogy. Field and micromorphologicial evidence suggests a polygenetic character of the Vertisols, resulting from changing soil drainage through time. Variations in soil drainage are quantified using proxy estimates of inferred soil processes such as base loss, leaching, lessivage, and oxidation. Using the CIA-K proxy, mean annual precipitation (MAP) estimates range from 519 to 1361 mm/yr. Changes in MAP correspond with variation in inferred soil processes. The flora of this time period, in response to variations in precipitation and soil drainage, also changes through time as evidenced by changes in abundance and depth of root traces. Reconstructed ecosystems range from sparse vegetative cover with shallow, tabular root systems in early Pennington soil development, to dense, deeply penetrating root systems suggestive of arborescent floral associations at the top of the succession approaching the Mississippian–Pennsylvanian boundary. This study provides greater resolution of changing climate and pedogenic processes than what is provided in previous studies of Late Mississippian climate, and suggests that the documented variability in paleosol types and soil drainage might represent the record of high-frequency climate changes likely associated with expansion and contraction of the paleo-Intertropical Convergence Zone (ITCZ).     

Reconstructing Mid-Pleistocene paleovegetation and paleoclimate in the Golan Heights using the δ(13)C values of modern vegetation and soil organic carbon of paleosols

The Golan Heights borders the Upper Jordan Valley on its eastern side and likely served as a prime foraging area for hominin groups that inhabited the Upper Jordan Valley during the Mid-Pleistocene. This study tests the hypothesis that Mid-Pleistocene climate in the Golan region was similar to that of the present day. Carbon isotope composition of present day plant communities and soil organic carbon from the Golan were compared to those of paleosols from Nahal Orvim to reconstruct Mid-Pleistocene paleoclimatic conditions. After correcting the paleosol values for recent changes in atmospheric carbon isotope values and potential biodegradation, the isotopic results show a strong similarity to those of present day local plants and soils. These results indicate that during the Mid-Pleistocene, the Golan was dominated by C₃ vegetation, shared similar climatic conditions with the present day, and displayed long-term environmental stability. The span of time of paleosol formation is unknown and might cover multiple climatic episodes; thus, although short climatic fluctuations may have occurred, their impact was not substantial enough to be detected in the Nahal Orvim paleosols. This study concludes that the Golan slopes provided hominins and large grazers with a reliable and highly nutritious foraging area that complemented the Jordan Valley riparian ecosystem.     

Second occurrence of the dinosauriform ichnogenus Atreipus in the western United States,Upper Triassic Chinle Group of Eastern Utah

Abstract

A newly discovered track in the Chinle Group north of Moab, Utah, is attributable to the ichnogenus Atreipus, an ichnotaxon that is relatively common in eastern North America (Newark Supergroup) but very rare in the Late Triassic of the western part of the continent. This is only the second report of the genus from the Chinle Group. Atreipus has been attributed to a silesaurid dinosauriform, and dinosauriform taxa are relatively abundant by skeletal material in the Late Triassic of western North America, but track evidence in the same units is dominated by ichnotaxa attributed to dinosaurs. The rarity of Atreipus is currently an anomaly in the region.     

Microbiology of vadose zone paleosols in south-central Washington State

Three unsaturated subsurface paleosols influenced by moisture recharge, including a highly developed calcic paleosol, were studied to investigate the microbiology of paleosols. Two near-surface paleosols, one impacted by moisture recharge and the other beyond the influence of recharge, were also sampled to directly assess the effect of moisture recharge on the activity and composition of the microbial community associated with paleosols. The highly developed paleosol had a higher population of culturable heterotrophs, a greater glucose mineralization potential, a higher microbial diversity based on colony morphology, and a more than 20-fold higher concentration of ATP than the two weakly developed paleosols. The recharged near-surface paleosol, as compared to the near-surface paleosol unaffected by recharge, had a lower population of culturable heterotrophs, smaller mineralization rate constant, and lower richness based on colony morphology. The recharged paleosols contained predominantly gram-negative isolates, whereas the paleosol unaffected by recharge contained predominantly gram-positive isolates. Storage at 4°C of subsurface and near-surface paleosol samples containing high water potential increased the population of culturable aerobic heterotrophs, decreased diversity in colony morphology, and increased first-order rate constants and decreased lag times for glucose mineralization. These results indicate that aerobic heterotrophs are present in deep vadose zone paleosols and that there is potential for stimulation of their in situ growth and activity.Offprint requests to: F. J. Brockman.     

Paleosols and paleoenvironments of the middle Miocene,Maboko Formation,Kenya

The middle Miocene (15 Ma) Maboko Formation of Maboko Island and Majiwa Bluffs, southwestern Kenya, has yielded abundant fossils of the earliest known cercopithecoid monkey (Victoriapithecus macinnesi), and of a kenyapithecine hominoid (Kenyapithecus africanus), as well as rare proconsuline (Simiolus leakeyorum, cf. Limnopithecus evansi) and oreopithecine apes (Mabokopithecus clarki, M. pickfordi), and galagids (Komba winamensis). Specific habitat preferences can be interpreted from large collections of primate fossils in different kinds of paleosols (pedotypes). Fossiliferous drab-colored paleosols with iron-manganese nodules (Yom pedotype) are like modern soils of seasonally waterlogged depressions (dambo). Their crumb structure and abundant fine root-traces, as well as scattered large calcareous rhizoconcretions indicate former vegetation of seasonally wet, wooded grassland. Other fossiliferous paleosols are evidence of nyika bushland (Ratong), and early-successional riparian woodland (Dhero). No fossils were found in Mogo paleosols interpreted as saline scrub soils. Very shallow calcic horizons (in Yom, Ratong, and Mogo paleosols) and Na-montmorillonite (in Mogo) are evidence of dry paleoclimate (300-500 mm MAP=mean annual precipitation). This is the driest paleoclimate and most open vegetation yet inferred as a habitat for any Kenyan Miocene apes or monkeys. Victoriapithecus was abundant in dambo wooded grassland (Yom) and riparian woodland (Dhero), a distribution like that of modern vervet monkeys. Kenyapithecus ranged through all these paleosols, but was the most common primate in nyika bushland paleosols (Ratong), comparable to baboons and macaques today. Mabokopithecus was virtually restricted to riparian woodland paleosols (Dhero), and Simiolus had a similar, but marginally wider, distribution. Habitat preferences of Mabokopithecus and Simiolus were like those of modern colobus monkeys and mangabeys. A single specimen of Komba was found in dambo wooded grassland paleosol (Yom), a habitat more like that of the living Senegal bushbaby than of rainforest galagids. A shift to non-forest habitats may explain the terrestrial adaptations of Victoriapithecus, basal to the cercopithecid radiation, and of Kenyapithecus, basal to the hominoid radiation. Both taxa are distinct from earlier Miocene arboreal proconsulines, oreopithecines and galagids.     

Unusual aetosaur armor from the Upper Triassic of West Texas,U.S.A.

We report two unusual aetosaur scutes from the Tecovas Member of the Dockum Formation, Chinle Group (upper Carnian) of Crosby County, Texas, U.S.A. Originally collected by University of Michigan expeditions in the 1920’s, these scutes cannot be assigned with certainty to any known species of aetosaurs known from the American Southwest. One of these scutes may be a cervical horn ofParatypothorax, and if so confirms the similarities of this aetosaur toDesmatosuchus in the possession of horned lateral spikes. The other is a paramedian scute of a new aetosaur taxon inadequately known at present to be assigned a formal name. These scutes indicate that aetosaurs were more diverse in the Chinle Group than currently known, but do not alter the robust Late Triassic biochronology based on aetosaurs.     

The oldest evidence of a sauropod dinosaur in the western united states and other important vertebrate trackways from grand staircase‐escalante national monument,Utah

Recent discoveries of abundant fossil footprints from the new Grand Staircase‐Escalante National Monument of southern Utah, have important implications for the spatial and temporal distribution of Mesozoic vertebrates in Triassic and Jurassic time. Since the monument's creation in 1996, fossil footprints have been reported from at least seven formations in the Mesozoic (Triassic‐Cretaceous) within the monument. By far the most significant of these discoveries are sauropod and theropod tracks from the upper part of the Middle Jurassic Entrada Sandstone and a large Apatopus trackway from the Late Triassic Chinle Formation. Tracks in the Entrada Sandstone are found at the same stratigraphic level as those in the Moab megatracksite, and so considerably extend this large ichnological complex. A wide‐gauge sauropod trackway (cf. Brontopodus) from this unit represents the first reported from the Entrada Sandstone, and so is the oldest known from the western United States. This trackway also reveals a tail trace, which is the first reliable record of a sauropod tail trace.     

Paleosol caliche in the New Haven Arkose,Newark Group,Connecticut

The New Haven Arkose is a 1500–2500 m sequence of fluvial red beds of Late Triassic and probably Early Jurassic age that accumulated in a tropical rift valley. Streams flowing from highlands along the valley deposited braided channel sand interbedded with overbank mud. At most outcrops in Connecticut, some of the beds of red mudstone and sandstone contain paleosol caliche with densely packed root casts and rhizoconcretions. These calcified mudstones and sandstones commonly show the initial stages of calcification where subspherical to vertically elongate calcite nodules with crystic plasmic (microspar) fabric replace up to 50% of the host rock. In more mature paleosols, coalescing calcite nodules replace 50–95% of the rock, accompanied by paleosol mosaics of pedotubules, peds, and laminated crystallaria. The best developed caliche profiles are capped by thin (0–10 cm) layers of nearly pure limestone with complex fabrics of nodules, microspar, veins, caliche clasts, laminae, and calcite cement. The caliche profiles accumulated when rates of sedimentation were low. Much of the time the tropical paleoclimate was semiarid, perhaps with 100–500 mm of seasonal rain and a long dry season.     

Paleoenvironmental reconstruction of middle Miocene paleosols bearing Kenyapithecus and Victoriapithecus, Nyakach Formation, southwestern Kenya

Paleosols in the middle Miocene (15 Ma) Nyakach Formation at Kaimogool, near Sondu, southwestern Kenya have yielded specimens of the early cercopithecoid Victoriapithecus macinnesi and the early kenyapithecine Kenyapithecus africanus, and can be used as evidence for the environmental mosaic occupied by these primates. Five distinct types of paleosols (pedotypes) are recognized in the Nyakach Formation section at Kaimogool South. The most common paleosols are reddish brown, silty calcareous profiles with blocky structure and large root traces (Ratong pedotype) which are interpreted as soils of well-drained, dry bushland or thicket (nyika). Weakly developed paleosols associated with paleochannels (Dhero pedotype) represent wooded grassland early in the ecological succession from streamside flooding. One of these paleosols has yielded a fossil flora of grasses and small-leaved dicots like those of modern semi-arid wooded grassland. Crumb structured, calcareous paleosols with iron-manganese nodules (Yom pedotype) are interpreted to represent seasonally waterlogged, wooded grassland (dambo or vlei). Thick, red clayey, calcareous paleosols with blocky ped structure and large root traces (Tut pedotype) are interpreted as soils of well-drained dry woodland. Other blocky-structured, gray to brown calcareous paleosols with iron-manganese nodules (Chido pedotype) are interpreted as soils of seasonally waterlogged, riparian dry woodland. Fossil soils, plants and gastropods are evidence of an unusually dry (300-500 mm mean annual precipitation) habitat for apes, consisting of a vegetational mosaic dominated by dry woodland, bushland and thickets with few areas of seasonally waterlogged grassland. Fossils of V. macinnesi are rare from Nyakach, but were found in paleosols representative of bushland and thicket habitats (Ratong). Fossils of the ape K. africanus were found within paleosols indicative of dry woodland (Tut). Other paleosol types representative of seasonally dry dambo grassland (Yom), colonizing grassland (Dhero) or riparian woodland (Chido) are also represented, but have not yet produced primate fossils.     

Xeric limestone prairies of eastern United States: Review and synthesis

Xeric limestone prairies (XLPs) are open, nonforested areas in which herbaceous plant communities occur on shallow, rocky soils derived from calcareous substrates. These grasslands are characterized by dominance of C₄ perennial grasses (particularlySchizachyrium scoparium) and are distributed in eastern United States from Missouri and Pennsylvania south to Arkansas and Georgia. XLPs occur in the Ozark Plateaus, Central Lowland, Interior Low Plateaus, Appalachian Plateaus, Ridge and Valley, and Coastal Plain physiographic provinces, and they are developed on Alfisols, Ultisols, Mollisols, Inceptisols, and Vertisols derived from Paleozoic limestones (also Eocene), dolomites, and calcareous shales. The C₄ perennial prairie grassS. scoparium is the characteristic dominant taxon in XLPs of eastern United States. However, C₃ perennial forbs are dominant in some sites, and C₄ annual grasses (Sporobolus spp.) may be locally dominant in shallow-soil-zone microsites. Thirteen taxa apparently are endemic, or nearly so, to this vegetation type, including eight in the Ridge and Valley in Alabama (Cahaba River valley), four in the Ozark Plateaus in Missouri and Arkansas, and one in the Ridge and Valley of West Virginia and Virginia. Various types of information are used to construct a conceptual model of the origin, maintenance, and successional dynamics of XLPs. Affinities of XLPs in eastern United States to other herbaceous vegetation types in eastern and western North America are discussed, and directions for future research are suggested.     

A Late Triassic Invertebrate Ichnofauna from Ghost Ranch,New Mexico

Invertebrate trace fossils are reported from the Late Triassic Chinle Formation at Ghost Ranch, New Mexico, for the first time. They occur in beds higher in the section than the Coelophysis Quarry. Six ichnotaxa are recognized: Steinichnus milfordensis, Planolites montanus, Palaeophycus tubularis, Taenidium serpentium, ?Arenicolites sp. and Skolithos sp. This ichnofauna is consistent with the Scoyenia ichnofacies, considered typical of lake margins in semiarid to arid regions.     

Phytoalexin production in lucerne roots inoculated withVerticillium albo-atrum

Summary Out of various soil and plant test methods tested for predicting response of rice to K application in soils of a rice growing valley region the Hanway and Heidal extractant neutralN NH₄ OAc turned out to be the best. The critical limit of extractable K was 160 ppm by the Hanway and Heidal extractant, and by the Bray's reagent 175 ppm. Critical K level in the rice plant is 0.4%. Correlations between the extractable K and K uptake were highly positive for various extractants: Hanway and Heidal, Morgan, Hunter and Pratt No. 2, Blanchet and Perigand and MacLean. Although majority of the soils of the region was Inceptisols followed by Alfisols and Vertisols, all soil types had a similar available nutrient status and a similar pattern in relative grain yields. K response was noticeable in Alfisols with respect to grain and straw yields. The grain P concentration in Vertisols, and straw K in Alfisols indicated the contribution of K towards the productivity of two soil groups.     

The Permian Moradi Formation of northern Niger: Paleosol morphology,petrography and mineralogy

Three basic paleosol morphologies, named Type A, Type B and Type C, are described from the middle–upper Permian strata of the Moradi Formation, Tim Mersoi Basin, northern Niger. The Moradi Formation is a typical alluvial redbed succession dominated by red mudrocks with fine to coarse-grained pebbly channel sandstones and matrix-breccias. Type A paleosols are hosted by well-sorted fine to medium grained trough cross bedded and massive sandstones and preserve abundant vertical to horizontal micritic and microspar calcite tubules, interpreted as rhizoliths. Lateral variability of rhizoliths in Type A paleosols, and their close association with fluvial channel-fill sediments suggests they are the roots of grove stands of phreatophytic vegetation that grew within unstable anabranching stream systems. Type B paleosols are hosted by mudrocks and preserve well-developed ped structure, abundant micritic calcite nodules and vertically-stacked micritic calcite nodular bodies, as well as rare calcite with satin-spar texture interpreted as a pseudomorphic replacement of pedogenic gypsum. The morphology of Type B paleosols suggests they were formed in well-drained floodplain deposits on stable landforms. Type C paleosols are similar to Type B but preserve pedogenic structures indicative of soil volume expansion and contraction, as well as more abundant Stage II pedogenic carbonate nodules. The morphology of Type C paleosols suggests that they developed periodically rather than seasonally in poorly-drained deposits that nevertheless occupied a relatively stable part of the landscape such as the plains flanking ephemeral lakes or sabkhas.X-ray diffraction analysis of the < 2 μm fraction from the Moradi Formation strata indicates that paleosol phyllosilicates are composed of illite, smectite, and occasionally kaolinite and talc. Illite is likely a detrital mineral, whereas smectite and kaolinite are likely pedogenic weathering products. The presence of talc in the Moradi Formation paleosols is unusual. It is limited to paleosol horizons that also preserve evidence for pedogenic gypsum accumulation and is therefore most likely related to a pedogenic weathering process. It is possible that this talc is a relatively low-temperature (~ 50–100 °C) diagenetic alteration product of pedogenic Mg–phyllosilicates such as sepiolite.The range of morphologies, petrographic textures and mineralogy of the paleosol profiles indicates semi-arid to hyper-arid climatic setting. This paleoclimatic reconstruction is in agreement with Middle and Late Permian conceptual paleoclimate models and quantitative general circulation models. Nevertheless, and in spite of an arid climate, Moradi paleosols and their host strata also indicate a relatively shallow groundwater table. Importantly, this shallow groundwater resource undoubtedly helped to support the moderately diverse fossil vertebrate assemblage and large-stature macrophytes preserved in the Moradi Formation.     

Pedogenesis of late Quaternary deposits, northern Kyonggi Bay, Korea: Implications for relative sea-level change and regional stratigraphic correlation

Late Pleistocene and early Holocene paleosols are described from construction pits and boreholes in the northern Kyonggi Bay, west coast of Korea. Thin-section petrography, chemistry, clay mineralogy and geotechnical properties of the paleosols were examined to infer relative sea-level fluctuations during the late Quaternary. Relict laminae and gradational contacts with underlying tidal rhythmites confirm that the late Pleistocene paleosol is a pedogenically altered tidal deposit. Illuvial clay coatings, rootlets and enrichment of kaolinite and chemically stable oxides indicate that pedogenesis occurred on a well-drained, stable surface during the last glacial period. Redoximorphic features, such as drab-colored root traces and sphaerosiderite, however, suggest that waterlogged conditions developed temporarily due to a rise of the water table at the end of the last glacial period. As sea level rose, an early Holocene paleosol formed in freshwater bog deposits, burying the late Pleistocene paleosol. The early Holocene paleosol has abundant sphaerosiderites and organic material. The presence of weakly developed illuvial clay coatings, oxidized siderites and pellets, however, indicates oxidizing condition associated with water-table fall occurred during the early Holocene. Despite the similarity in the degree of chemical and clay mineralogical weathering, the late Pleistocene paleosol is distinguished from its early Holocene counterpart by thicker and more abundant illuvial clay coatings, more Fe₂O₃ and a greater degree of consolidation. Duration of pedogenesis might be a primary cause for the difference of the pedofeatures with climate playing a secondary role. The widespread presence of similar late Pleistocene paleosols highlights its significance as a key stratigraphic marker for regional correlations along the west coast of Korea.     

Reassessment of the paleoenvironment and preservation of hominid fossils from Hadar, Ethiopia.

Samples of paleosols from locality AL-333, known for numerous specimens of Australopithecus afarensis, were analyzed in order to reconstruct the original soils and environment of burial of the associated fossil hominids. The bones were found in swale-like features, within the calcareous and coarse-grained basal portion of a paleosol. This is more like an assemblage of bones buried during a single depositional episode, such as a flood, than an assemblage accumulated on a soil over a long period of time by carnivores or other means of death. What killed the hominids remains unclear, but considering the association of originally disarticulated bones of such hydraulically distinct types as phalanges and maxillae, it is very likely that they died and partially rotted at or very near this site. The paleosols at AL-333, here named the Fo and Go clay paleosols, have calcareous rhizoconcretions, granular surface horizons, prismatic peds, and shallow calcareous nodules and stringers like soils now supporting grassy woodland in semiarid regions. Although this group of hominids was buried in streamside gallery woodland, there is evidence from Laetoli, Tanzania, that A. afarensis ventured out into open wooded grassland as well. Evidence for this should be sought from other paleosols at Hadar.     

THE SYSTEMATIC POSITION OF EOGINKGOITES

Eoginkgoites is a fan-shaped, imparipinnate leaf with a short rachis and long petiole. It was first described from the Upper Triassic Newark Group of Pennsylvania by Bock who assigned the fossil to the Ginkgoales. The fossil has also been found in the Upper Triassic Chinle Formation in Utah and Arizona and in the Newark Group in North Carolina. Investigation of the well-preserved specimens found in the Chinle Formation shows that the leaf has anastomosing venation, a marginal vein and paracytic (syndetocheilic) stomata. These characters indicate that the leaf is bennettitalean and Eoginkgoites is reassigned to the Bennettitales although its shape is perplexing. Eoginkgoites may be an important index fossil to the lower Upper Triassic (middle Carnian) rocks of North America.     

Paleosols, stable carbon isotopes, and paleoenvironmental interpretation of Kanapoi, Northern Kenya

This study uses the interpretation of paleosol features at Kanapoi, Kenya (4.2-3.4 Ma) to reconstruct the ecosystem occupied by Australopithecus anamensis. The paleosols at Kanapoi provide a unique and fortuitous opportunity, in that the bulk of the hominid specimens derive from paleosols, providing direct evidence of the environment that the Kanapoi hominids occupied. Seven named types of paleosols are recognized at Kanapoi, each representing a trace fossil of the local ecosystem during soil formation. The hominid-bearing Dite paleosols provide evidence that A. anamensis inhabited areas of semi-arid, seasonal climate regimes with mean annual precipitation ranging from about 350-600 mm. The in situ hominid collections from Dite paleosols show that A. anamensis at least occasionally occupied relatively open low tree-shrub savanna vegetation formed in well drained settings, and may have preferred these conditions over other poorly drained soils. The relatively open conditions of Dite paleosols existed within a spatially variable ecosystem, characterized by a mosaic of environments, ranging from forb-dominated edaphic grassland to gallery woodland, providing a larger view of the mixed ecosystem in which A. anamensis lived. Synthesis of paleoenvironmental indicators of A. anamensis at Kanapoi and Allia Bay, Kenya suggests that as early as 4 Ma hominids thrived in varied ecosystems.     

Comparative analysis of the functional activity and composition of hydrolytic microbial complexes from the lower Volga barrow and modern chestnut soils

The structure and specific characteristics of the hydrolytic microbial complexes from chestnut paleosols buried under the barrows of different ages (～4500 and ～3500 years) was compared with their modern analogue in microcosm experiments. Potential activity of the hydrolytic complex of the microbial community of the barrow paleosols was found to be higher than in the modern soil complex. The share of metabolically active cells revealed by FISH after the introduction of a growth-stimulating polysaccharide into the paleosol microcosm was 50% of the whole prokaryotic cell number. The paleosol community exhibited a more pronounced response to addition of the substrate than the modern soil community. The differences in the phylogenetic taxonomic structure of the prokaryotic metabolically active hydrolytic complex in the buried and modern soils were revealed. The hydrolytic complex of modern soil was more diverse, while the dominant hydrolytic organisms revealed in paleosols were unicellular and mycelial Actinobacteria, as well as Proteobacteria.