pedogenic carbonate proxies for amount and seasonality of precipitation in paleosols the depth to carbonate nodular bk horizon in soils d in cm is correlated with mean annual precipitation p in mm so that bk horizons are deep in subhumid regions but shallow in semiarid regions previous quantifications of this relationship are unchanged by this new compilation of 807 soils p 137 24 6 45 d 0 013 d 2 where r 2 0 52 and standard error s e 147 mm in most north american postglacial soils the bk horizon is thin and well defined whereas in monsoonal tropical soils of pakistan and kenya the bk horizon is thick and diffuse data from 675 modern soils define the relationship between the thickness of soil with nodules t in cm and mean annual range of precipitation m in mm difference between monthly means of wettest and driest months m 0 79 t 13 71 where r 2 0 58 and s e 22 mm the relationship between carbonate nodule size s in cm and soil age a in ka is quantified by 9 radiocarbon dated soils from las cruces new mexico a 3 92 s 0 34 where r 2 0 57 and s e 1 8 k y these transfer functions are applied to reconstructing paleoclimatic change from paleocene eocene paleosols of the north horn formation and flagstaff limestone of axhandle canyon utah the terminal paleocene spike of warmth recorded by fossil plants in nearby wyoming was coincident with a brief peak in both mean annual precipitation and mean annual range of precipitation in utah

the north hawaiian ridge current a comparison between an analytical theory and some prior observations abstract a previously developed analytic model of rossby wave induced mean current along lateral boundary is least squares fitted to the geostrophic current derived from two closely sampled hydrographic sections windward northeast of the hawaiian islands the field of rossby waves used to predict the current called the north hawaiian ridge current was determined by earlier studies of the north pacific the hydrographic surveys were conducted in january 1974 and october 1975 and were meridional i e roughly orthogonal to the ridge the model fits the data fairly well

environments of formation and controls on spatial distribution of calcite cementation in plio pleistocene fluvial deposits new mexico u s a abstract the sierra ladrones formation is the uppermost syn rift sedimentary unit of the rio grande rift in central new mexico in the vicinity of the study site it was deposited in a variety of fluvial subenvironments portions of the formation are strongly cemented by calcite forming resistant ledges in otherwise poorly consolidated sediment the calcite exhibits a wide range of macroscopic and microscopic textures and structures which formed in different hydrologic environments including vadose nonpedogenic vadose pedogenic and phreatic phreatic cements are characterized by sparite with uniform disseminated isopachous poikilotopic and drusy textures vadose nonpedogenic by micrite with meniscus textures and vadose pedogenic by textures similar to those in the vadose nonpedogenic environment plus macroscopic features such as root structures destruction of primary sedimentary textures and a red hue many of the cements are of mixed vadose phreatic origin with vadose micrite formation preceding phreatic sparite the calcite is near end member in composition with only minor substitution of trace elements sr mg mn and fe for ca in the calcite structure vadose micrite cements generally have a higher trace element content than phreatic sparite perhaps as a result of more rapid precipitation in the vadose zone carbon isotope values range from 4 7 to 3 5 pdb and 18o values range from 10 3 to 7 2 pdb cements that are dominantly vadose have a wider range of 13c values and are more 13c depleted overall than phreatic cements oxygen values are similar for both vadose and phreatic cements at large scales i e several meters to decameters vertical dimension calcite is present preferentially in coarse grained sediments that had high pre cementation saturated permeabilities relative to uncemented finer grained strata at smaller scales i e several meters or less vertical dimension however there is no clear relationship between degree of cementation and pre cementation permeability at these scales calcite cement is present preferentially in areas that contain early vadose calcite this suggests that at large scales cementation was controlled by pre cementation permeability perhaps due to a greater flux of ca2 and or hco3 in permeable horizons whereas at smaller scales within high permeability units the distribution of cementation was controlled by other factors such as the presence of nucleating material

do red beds indicate paleoclimatic conditions a permian case study abstract terrestrial red beds have long been interpreted as desert deposits by comparison with modern red deserts more recently red beds have been interpreted as evidence of seasonally dry conditions and a permo triassic pangean monsoon red beds of cala viola sardinia are identified as paleosols and used to reconstruct late permian paleoclimatic conditions reconstruction of paleoenvironmental conditions based on the paleosols of the cala viola indicates warm humid conditions with no evidence of dry conditions as in a desert or of extreme seasonality as in a monsoon instead it is suggested that the red color of the paleosols is a result of former good drainage and that red color in general does not indicate specific paleoclimatic conditions

potentially acid sulfate soils in relation to landforms and geology summary on the basis of analytical results from about 8000 augerings the wetlands of jutland denmark were subdivided into four map units without potential acid sulfate soils and with up to 20 20 to 50 and more than 50 of the augering containing potential acidity this map was combined with existing geomorphological and geological maps in order to estimate the frequency of potentially acid sulfate soils in wetlands in different landforms of the total wetland area one fifth of jutland about a quarter is potentially acid sulfate the proportion ranges from half in the coastal march area to about a fifth in the other marine landforms in the non marine landforms more than a third of the wetlands in saale glaciation landscape and in the outwash plains are potentially acid sulfate in the wetlands of the other non marine landforms the proportion is less than a fifth this difference is explained by geological substratum in northern jutland this is pure cretaceous limestone while in the rest of jutland tertiary pyritic mica rich sand and clay dominate the development of potential acidity in the wetlands is probably due to a migration of iron and sulfur from these deposits or from tills with tertiary fragments to the wetlands where the iron and sulfur have precipitated as pyrite in the organic rich sediments

the distinction between ground water gley and surface water gley phenomena in tertiary paleosols of the ebro basin ne spain abstract in studies of paleosols the distinction iron segregation due to either surface water or ground water fluctuatins is hardly ever made recognition of subsequent hydromorphic phases is even more rare nevertheless such distinctions can be made and are very useful in determining the paleoenvironment in this study we demonstrate that subsequent stages of hydromorphism and their sequence can be recognized in paleogene paleosols of the ebro basin it appears that in these carbonate rich hydromorphic oils goethite iron segregations are due to ground water influence while hematitic segregations are due to surface water the preservation of original mineralogy in this case is due to absence of late diagenetic transformations the results contradict the thesis that red colours in such paleosols would be the result of the late diagenesis in the studied samples mottledcolour patterns frequently indicate fairly advanced soil formation although weathering of primary minerals is almost absent detailed study of colour patterns gives much additional information on the post depositional environment

nonmarine sequence stratigraphy updip expression of sequence boundaries and systems tracts in a high resolution framework cenomanian dunvegan formation alberta foreland basin canada ten allomembers labeled j a have been mapped in the deltaic dunvegan formation using 2340 wells and 63 outcrop sections each allomember spans about 200 k y is bounded by regional transgressive surfaces and consists of 3 10 component shingles apparently of autogenic origin allomembers h e are discussed in this article their internal stacking patterns and bounding surfaces permit interpretation as depositional sequences sequences h f have a sigmoidal prismatic geometry downlap to the southeast and thin northwest onto the coastal plain no differential thickening exists toward the orogen in the southwest in contrast sequence e thickens markedly toward the northwest the tabular geometry of sequences h f suggests accommodation was controlled by sea level change whereas the wedge geometry of sequence e suggests significant tectonic tilting subaerial unconformities that bound valleys and extend onto adjacent interfluve paleosols can be traced 120 330 km updip into outcrop the base of each sequence is characterized by shoreline backstep of 80 150 km transgressive and highstand shingles in each sequence comprise marine deltaic deposits that pass landward into coastal plain strata falling stage shingles offlap seaward with little or no nonmarine equivalents updip whereas lowstand shingles show renewed coastal onlap in outcrop three nonmarine systems tracts are recognized 1 a channel dominated low accommodation systems tract fills valleys up to 35 m deep and is equivalent to the early transgressive systems tract begin page 1968 2 a lacustrine dominated high accommodation systems tract comprises mudstone enclosing ribbon channel sandstones blankets interfluves and forms the bulk of each sequence it is equivalent to late transgressive and early highstand systems tracts 3 a paleosol dominated low accommodation systems tract occupies the upper part of each sequence and is capped by the sequence boundary it is equivalent to the late highstand systems tract sequence bounding interfluve paleosols represent tens of thousands of years of pedogenesis related to slow aggradation followed by fluvial entrenchment and clastic bypass and represent the late highstand falling stage lowstand and early transgressive systems tracts coastal plain deposits record only part perhaps

from cyclothems to sequences the record of eustasy and climate on an icehouse epeiric platform pennsylvanian permian north american midcontinent the stratigraphic succession of the north american midcontinent contains a high resolution 100 000 year record of sea level and climate change spanning the pennsylvanian permian boundary outcrop based sequence stratigraphic analysis on the upper wabaunsee admire and lower council grove groups in kansas and nebraska reveals a hierarchy of fifty one fifth order meter scale cycles grouped into five fourth order composite sequences fifth order cycles are bounded by subaerial unconformities in nearshore settings and correlative conformities in offshore settings and are therefore very thin depositional sequences lowstand systems tracts observed only in nearshore deposits are expressed as sandy incised valley fills in these meter scale cycles transgressive systems tracts which are dominated by carbonate deposition include coastal evaporites indicating arid climatic conditions highstand systems tracts which are dominated by siliciclastic deposition include thin but persistent coals in muddy coastal successions indicating humid climatic conditions paleosols at sequence boundaries evolve from vertic to calcic indicating climate change from relatively humid to relatively arid conditions during subaerial exposure this indicates that relatively arid climate coincided with eustatic lows while relatively humid climate coincided with eustatic highs on this low latitude platform composite sequences are bounded by subaerial angular unconformities and display a transgressive regressive stacking pattern of meter scale cycles the high resolution stratigraphic record of the midcontinent helps constrain the rate and magnitude of environmental change in ancient icehouse conditions and can serve as a baseline of environmental change for comparison with other coeval successions

palaeosols and sequence stratigraphy of the lower permian abo member south central new mexico usa the relationship between palaeosols and sequence stratigraphy is tested in the lower permian abo member south central new mexico by comparing interfluve and fluvial terrace palaeosols with palaeosols that developed within lowstand fluvial deposits interfluve and fluvial terrace palaeosols consist of primary pedogenic features including vertical root traces vertic structures stage ii and iii pedogenic calcite and translocated clay argillans which are cross cut or replaced by low aluminium goethite gley colour mottling sparry calcite veins and ankerite the polygenetic character of the palaeosols is consistent with initial development for several thousand to tens of thousands of years on well drained interfluves or fluvial terraces followed by waterlogging due to invasion by a rising water table that locally may have been brackish in contrast lowstand fluvial sediment that filled incised valleys contains only rooted and vertic palaeosols whose immaturity resulted from high aggradation rates palaeosols similar to those in the abo member have been recognized in other ancient strata and when combined with highresolution correlation provide evidence for interpretation of sequencestratigraphic surfaces and systems tracts

late carboniferous cyclothems and alluvial paleovalleys in the sydney basin nova scotia cyclothems are documented for the first time in alluvial to coastal plain strata west phalian d to stephanian of the sydney basin nova scotia well developed cyclothems commence with an extensive carbonaceous lime stone or shale with a restricted marine biota that indicates maximal flooding succeeding gray detrital bay and lake fills with distributary channel deposits are overlain by stacked channel deposits paleovalley fills that mark an abrupt basinward facies shift and a profound change in alluvial style channel fills and red vertisols were deposited on an alluvial plain above the filled valleys and the paleovalley is equated with thick vertisols in adjacent inter fluve areas the cyclothems are capped by gray coastal deposits with economic coals agglutinated foraminifera are present in seat earths beneath the coals which formed as a result of a brief stillstand during transgression red mudstones pass laterally into gray detrital bay fills in regions of greater subsidence associated with faulted basement blocks poorly developed cyclothems are bounded by extensive but split coals and autogenic effects partially obscure allogenic patterns mean cyclothem duration approximates 200 ka

paleopedologic and paleohydrologic records of precipitation seasonality from early pennsylvanian underclay paleosols u s a underclays in the crooked fork group lower pennsylvanian atokan langsettian in eastern tennessee u s a are paleosols associated with fourth order depositional sequences that record changing paleohydrologic conditions during their formation climate changes possibly milankovitch driven resulted in evolution of soil landscapes from well drained seasonally wet floodplains and delta plains dominated by vertic vertisol like paleosols to very poorly drained everwet swamps dominated by sideritic gley paleosols coals paleohistosols cap most underclays and record peat swamp development during everwet conditions followed by marine submergence pedogenic slickensides and angular blocky ped structures in conjunction with illuviated clay pore fillings and sepic plasmic microfabric indicate an initial better drained phase of paleosol development stage i gley overprinting characterized by drab low chroma paleosol colors fe reduction in upper portions of paleosols sideritic rhizocretions sphaerosiderite and pyrite nodules extensive leaching and translocation of alkali and alkaline earth elements and kaolinitization of smectites and hydroxy interlayer vermiculite hiv indicate a later poorly drained stage of paleosol development characterized by saturated conditions moderate to low eh and low ph stage ii as well as peat swamp development lastly burial and juxtaposition of marine facies on top of terrestrial deposits terminated paleosol and peat development stage iii paleosols likely formed under conditions of marked seasonality of rainfall judging from both modern analog systems in sumatra and pennsylvanian paleoclimate models the chemical index of alteration without potash cia k was used as a proxy for atokan paleoprecipitation estimated as 1300 mm yr this estimate is comparable with mean annual precipitation map in modern tropical to subtropical rainy environments

the distribution and discrimination of shallow authigenic carbonate in the pliocene pleistocene palomas basin southern rio grande rift nine types of authigenic carbonate are present in the pliocene pleistocene alluvial fan and axial fluvial sediment of the palomas half graben in the southern rio grande rift pedogenic and other vadose carbonate includes 1 pedogenic carbonate of stage ii and stage iii morphology underlying bw and bt horizons 2 mudstones in which the carbonate nodules may be pedogenic or the result of shallow groundwater invasion of the vadose zone 3 pedogenic calcic nodules and tubules in eolian sand and 4 gully bed cement of proximal fan conglomerates formed by infiltration and evaporation of surface runoff shallow groundwater carbonate exists as 5 thin 30 50 cm massive beds with an upper fringe of nodules and tubules precipitated at the water table and in the capillary fringe 6 thick 1 5 3 m massive beds deposited by lateral flow of groundwater or at springs and 7 thin 30 cm calcified root mats associated with near surface water saturated sediment or springs phreatic spar cements 8 occupy the interstices of conglomerates and sandstones and locally exist as 9 oriented concretions groundwater carbonates are best developed near the toes of the large hanging wall derived alluvial fans whereas phreatic cement preferentially exists in footwall derived alluvial fan conglomerates pedogenic carbonate is distinguished from groundwater carbonate by the association with other diagnostic paleosol horizons a predominantly vertical arrangement of root traces peds desiccation cracks and calcic tubules and by gradational contacts the 13 c and 18 o values are similar among pedogenic and shallow groundwater carbonate although locally nodules in eolian sand and gully bed cement have higher 18 o values perhaps due to the effects of evaporation some phreatic cements may be distinguished from pedogenic and shallow groundwater carbonate by lower values of 13 c and 18 o authigenic carbonate in footwall derived alluvial fan sediment has consistently higher values of 13 c than that in hanging wall derived sediment which may reflect differences in vegetative type and or density on either side of the basin

paleoclimatic controls on stable oxygen and carbon isotopes in caliche of the abo formation permian south central new mexico u s a abstract the stable oxygen and carbon isotopic composition of caliche in fluvial and supratidal rocks of the abo formation permian south central new mexico is controlled by paleoclimate and depositional environment fluvial caliche consists of low mg calcite nodules and vertically oriented tubules that display stage ii texture micrite matrix support brecciation ooids pisoliths aveolar septal texture and peloids are common in the fluvial caliche and along with red color and slickensides in the host shale indicate pedogenesis in a well oxidized vadose zone in contrast periodic waterlogging of the supratidal paleosols probably due to high water table is indicated by drab colors carbonaceous flecks horizontal rhizoliths and the paucity of vadose textures in the stage ii caliche n dules stable oxygen isotopes are similar in the fluvial and supratidal caliches and range from 21 6 to 30 5 smow the data exhibit a crude bimodality and 18o enrichment with a decrease in age higher in the section consideration of these data in the context or temperature relations suggests that 1 surface waters responsible for caliche formation increased in 18o from roughly 8 to 1 over the 18 m y time interval that separated the lowest stratigraphic nodule horizon from the highest 2 the inc easing 18o values also reflect a warming trend approximately 15 to nearly 3 c in the mean monthly temperature over this same time period with perhaps an associated increase in permian ocean temperatures and 3 the significant variation in 18o from oldest to youngest caliche was probably enhanced by the amount effect such that as the temperature increased the amount of precipitation decreased resulting in high 18o values caliches in the abo are enriched in heavy carbon 7 2 to 1 5 pdb compared to that of soil carbonate derived exclusively from c plants 12 pdb and the supratidal caliches contain somewhat heavier carbon compared to the fluvial caliche the 13c values for both environments increase with a decrease in caliche age these results indicate that as the temperature increased and rainfall decreased with time the level of c3 plant productivity apparently declined allowing a greater influx of atmospheric co2 into the soil this can only occur when soil respiration rates are quite low or at very sha low depths less than 10 cm or both atmospheric co2 seems to have invaded the supratidal soils to a somewhat greater extent than the fluvial soils

evolution of an ancient coastal plain palaeosols interfluves and alluvial architecture in a sequence stratigraphic framework cenomanian dunvegan formation ne british columbia canada to date discussion of changes in alluvial style and in the character of palaeosols in relation to changes in accommodation and sediment supply on floodplains has primarily been from a conceptual standpoint few case studies are available against which to test ideas one hundred and thirty metres of non marine strata of the dunvegan formation were examined in 14 closely spaced sections in the canyon of the kiskatinaw river ne british columbia canada this site was located about 120 km inland from the transgressive limit of the contemporary marine shoreline and represents almost exclusively freshwater environments fluvial channels in the kiskatinaw river section are of two types small single storey very fine to fine grained sandstone ribbons with w t ratios 30 are interpreted as the deposits of meandering rivers filling incised valleys interchannel facies include the deposits of crevasse channels and splays lakes floodplains and palaeosols floodplain palaeosols consist of laterally heterogeneous simple palaeosol profiles and pedocomplexes similar to modern entisols inceptisols and hydromorphic soils interfluve sequence bounding palaeosols adjacent to incised valleys are laterally continuous up to 3 m thick and can be reliably identified using a combination of 1 stratigraphic position 2 field observations such as thickness structure colour degree of rooting and 3 micromorphological features such as evidence of bioturbation clay coatings ferruginous features and sphaerosiderite interfluve palaeosols are similar to modern alfisols and ultisols correlation of the local stratigraphic succession with the regional sequence stratigraphic framework based on 2340 well logs and 60 outcrop sections shows that the vertical changes in coastal plain character more coals and lakes vs more pedogenesis can be related to relatively high frequency base level cycles eustatic that are expressed as transgressive regressive marine cycles in downdip areas regional isopach maps show that these cycles were progressively overprinted and modified by an increasing rate of tectonic subsidence in the north and west the character of palaeosols developed on aggrading floodplains primarily reflects local sediment supply and drainage in contrast well developed interfluve palaeosols record pedogenesis during periods of reduced or negative accommodation base level fall vertical changes in floodplain palaeoenvironments and palaeosol types reflect changes in accommodation rate the detailed micromorphological analysis of interfluve palaeosols represents a powerful application of an under used technique for the recognition of key surfaces in the geological record this has broad implications for non marine sequence stratigraphy

palaeosols as indicators of geomorphic stability in two old red sandstone alluvial suites south wales palaeosols fossil soils are abundant in the alluvial late silurian early devonian moor cliffs formation and rat island mudstone freshwater west formation of south dyfed south wales the palaeosols occur in thick mudstones deposited on floodplains under a seasonal semi arid climate and represent vertisol type soils simple single profiles are rare and most of the mudstone intervals exhibit complex overprinted profiles however a major difference exists between the palaeo vertisols in each of the two units studied the moor cliffs formation contains thick floodplain intervals with evidence of frequent erosion and reactivation of earlier soil horizons the associated coarser channel deposits mainly represent ephemeral streams the alluvial system was unstable flashy and prone to extensive stripping of stored floodplain sediment arroyos unstable ephemeral stream channels probably developed during this interval evidence for any marine influence on soil development is missing and previous speculations that the formation may represent deposition in an upper intertidal or supratidal system are not supported the rat island mudstone represents a complete contrast in that there was little or no stripping of floodplain sediments the channel deposits are typically of the fining upwards type representing more stable low sinuosity channels and with ephemeral stream floods by integrating the palaeosols a more detailed picture of the geomorphic history of these units can be formulated comparison with contemporary drainage basins indicates that a change in climate was a possible cause for the differences between the two units less frequent and more severe storms occurring during the deposition of the rat island mudstone

co2 forced climate and vegetation instability during late paleozoic deglaciation the late paleozoic deglaciation is the vegetated earth9s only recorded icehouse to greenhouse transition yet the climate dynamics remain enigmatic by using the stable isotopic compositions of soil formed minerals fossil plant matter and shallow water brachiopods we estimated atmospheric partial pressure of carbon dioxide pco2 and tropical marine surface temperatures during this climate transition comparison to southern gondwanan glacial records documents covariance between inferred shifts in pco2 temperature and ice volume consistent with greenhouse gas forcing of climate major restructuring of paleotropical flora in western euramerica occurred in step with climate and pco2 shifts illustrating the biotic impact associated with past co2 forced turnover to a permanent ice free world

recognition of interfluve sequence boundaries integrating paleopedology and sequence stratigraphy in shallow marine and coastal plain strata sequence boundaries are easily recognized at the base of incised valley fills between valleys however it is more difficult to recognize sequence boundaries where they are expressed as interfluve paleosols we suggest that interfluve paleosols can be most reliably identified using a combination of 1 stratigraphic position 2 field observations such as thickness structure color and degree of rooting and 3 micromorphological features such as bioturbation fabric clay coatings ferruginous features and siderite and barite only micromorphology permits recognition of temporal changes in drainage surface stability and protracted pauses in sedimentation that typify these surfaces this three part approach has been successfully employed to identify interfluve sequence bounding paleosols in the cenomanian dunvegan formation in alberta and british columbia canada

impact of longer term modest climate shifts on architecture of high frequency sequences cyclothems pennsylvanian of midcontinent u s a abstract pennsylvanian glacioeustatic cyclothems exposed in kansas and adjacent areas provide a unique opportunity to test models of the impact of relative sea level and climate on stratal architecture a succession of eight of these high frequency sequences traced along dip for 500 km reveal that modest climate shifts from relatively dry seasonal to relatively wet seasonal with a duration of several sequences 600 000 to 1 million years had a dominant impact on facies sediment dispersal patterns and sequence architecture the climate shifts documented herein are intermediate both in magnitude and duration between previously documented longer term climate shifts throughout much of the pennsylvanian and shorter term shifts described within individual sequences climate indicators are best preserved at sequence boundaries and in incised valley fills of the lowstand systems tracts lst relatively drier climate indicators include high chroma paleosols typically with pedogenic carbonates and plant assemblages that are dominated by gymnosperms mostly xerophytic walchian conifers the associated valleys are small 4 km wide and 20 m deep and dominated by quartz sandstones derived from distant source areas reflecting large drainage networks transgressive systems tracts tst in all eight sequences generally are characterized by thin extensive limestones and thin marine shales suggesting that the dominant control on tst facies distribution was the sequestration of siliciclastic sediment in updip positions highstand systems tracts hst were significantly impacted by the intermediate scale climate cycle in that hsts from relatively drier climates consist of thin marine shales overlain by extensive thick regressive limestones whereas hsts from relatively wetter climates are dominated by thick marine shales previously documented relative sea level changes do not track the climate cycles indicating that climate played a role distinct from that of relative sea level change these intermediate scale modest climate shifts had a dominant impact on sequence architecture this independent measure of climate and relative sea level may allow the testing of models of climate and sediment supply based on modern systems

eustatic control on alluvial sequence stratigraphy a possible example from the cretaceous tertiary transition of the tornillo basin big bend national park west texas u s a paleosol bearing alluvial strata of latest cretaceous and earliest tertiary age are continuously exposed along dawson creek in big bend national park west texas u s a and exhibit a three tier hierarchy of depositional cyclicity meter scale fluvial aggradational cycles facs occur as fining upward successions that are gradation ally overlain by paleosols or are sharply overlain by the coarser grained base of the succeeding fac without an intervening paleosol facs stack into decameter scale fluvial aggradational cycle sets fac sets that also fine upward and from base to top contain either a grad ual upsection increase in soil maturity and soil drainage or a somewhat symmetrical pattern of increasing and decreasing paleosol maturity longer period trends of fac thickness lithologic proportions paleosol maturity and paleosol drainage indicate that two complete and two partial hectometer scale fluvial sequences occur within the study in terval from base to top each sequence is characterized by an asym metric increase and decrease in fac thickness a decrease in the pro portion of sand prone fluvial facies an increase in paleosol maturity and better paleosol drainage whereas facs and fac sets are interpreted to record cyclic epi sodes of channel avulsion and stability and longer term avulsive chan nel drift within the alluvial valley respectively fluvial sequences may coincide with third order sea level changes within the north american western interior seaway as such the cretaceous tertiary k t transition within the tornillo basin may provide an example of me gascale stratigraphic cyclicity that is controlled by eustatic sea level within a fully fluvial succession thickening and thinning successions of facs record a third order period of accelerating transgressive equivalent and decelerating highstand equivalent base level rise and subsequent base level fall falling stage to lowstand equivalent se quence boundaries are placed at the sharp inflection between thinning and thickening facs sand prone facies and immature more poorly drained paleosols are associated with the transgressive equivalent por tion of each sequence and mudrock dominated overbank facies and their associated mature well drained paleosols are associated with the highstand and falling stage equivalent

cyclic sedimentation in the mixed siliciclastic carbonate abo hueco transitional zone lower permian southwestern new mexico abstract in southwestern new mexico lower permian wolfcampian rocks grade southward from nonmarine siliciclastics abo and earp formations to marine carbonates hueco and horquilla formations a transitional zone between siliciclastic and carbonate facies trends east northeast across southwestern new mexico and consists of 64 to 186 m of cyclically interbedded siliciclastic and carbonate rocks which were deposited in tidal flat and shallow marine environments shallow marine facies include fossiliferous limestone and olive gray shale tidal flat facies consist of 1 ripple laminated sandstone which was deposited on intertidal sandflats near mean low tide 2 mixed sandstone shale which was deposited on an intertidal flat shoreward of the ripple laminated sandstone facies and 3 nodula shale which is characterized by pedogenic calcareous nodules and was deposited in a supratidal setting the intertidal facies are truncated by or grade laterally into rare channel sandstones which represent tidal creek or estuarine facies in addition to siliciclastic tidal flat deposits a few beds of laminated carbonate also were deposited in the intertidal zone vertical sequence analysis aids in delineating three types of depositional cycles asymmetrical cycles display the vertical sequence basal fossiliferous limestone olive gray shale ripple laminated sandstone mixed sandstone shale nodular shale and record shoreline progradation the asymmetrical cycle is always overlain by fossiliferous limestone which indicates a major transgression that inhibited siliciclastic sedimentation a common symmetrical cycle consists of fossiliferous limestone olive gray shale ripple laminated sandstone olive gray shale fossiliferous limestone and indicates systematic seaward and landward migration of facies zones associated with small scale sea level changes a less common symmetrical cycle involves laminated carbonate fossiliferous limestone aminated carbonate cyclic sedimentation in abo hueco transitional strata is most likely the result of glacial eustatic sea level fluctuations

stratigraphic implications of meteoric sphaerosiderite 18o values in paleosols of the cretaceous albian boulder creek formation ne british columbia foothills canada abstract the md 80 08 coal exploration core from the albian boulder creek formation of northeastern british columbia contains 90 m of alluvial strata that underwent extensive pedogenic modification gleyed colors pedogenic slickensides clay coatings mottling sphaerosiderite and sedimentary pyrite characterize the paleosols the isotopic compositions of 30 sphaerosiderite bearing horizons commonly show trends of invariant 18o and variable 13c values equal area plots of 18o vs 13c were used to construct meteoric sphaerosiderite lines msls the msls indicate that meteoric groundwater compositions ranged from approximately 11o oo to 16o oo smow the sphaerosiderite 18o values indicate formation in shallow groundwaters predominantly recharged by local precipitation the sphaerosiderite isotopic compositions are a proxy record of mid cretaceous precipitation and are useful for quantifying changes in the hydrologic cycle during humid greenhouse periods micromorphology of a 1 15 meter interval 69 75 68 6 m with a 1 31o oo increase in the average 18o values records a polygenetic history of paleosol development the pedocomplex has a four stage developmental history characterized by 1 an initial well drained phase with wet dry cycles and relatively low baselevel 2 erosion baselevel rise and coarser grained sedimentation 3 saturated reducing soil conditions high baselevel with some marine influence on pedogenesis and 4 meteoric water dominated hydromorphic soil conditions high baselevel and sphaerosiderite precipitation the 18o excursion recorded through this interval reflects minor mixing of marine and meteoric groundwaters the modal abundance of pyrite and increased mg ca mg and mg fe cation ratios in the sphaerosiderites further substantiate marine influence on pedogenesis the alluvial section of the boulder creek formation is aggradational and several changes in baselevel recorded in the paleosols are interpreted to have been driven by minor parasequence scale changes in relative sea level

currents observed north of oahu during the first five years of hot abstract shipboard adcp sections from 30 hawaii ocean time series cruises over a 5 year period show a mean flow 15 degrees north of west reaching a maximum of 17 cm s 1 about 50 km north of oahu this north hawaiian ridge current is highly variable from cruise to cruise and from year to year it was generally strong in the sections 1988 1991 and weak or absent in 1992 and 1993 there is no prominent annual cycle unresolved short period oscillations are so energetic as to obscure the mean current in individual sections the 5 year mean is highly significant however at five times the estimated standard error currents also were measured with a shipboard adcp during the nominally 3 day occupations of the hot station aloha the mean over 32 cruises was near 6 cm s 1 in magnitude at all depths from 20 to 200 m but the median was near zero hence the northern boundary of the north hawaiian ridge current was usually south of aloha the inter cruise standard deviation of velocity varied from 22 cm s 1 at 20 m to 11 cm s 1 at 200 m for the zonal component and 13 cm s 1 to 8 cm s 1 for the meridional component intra cruise variability during the 17 cruises with the best sampling in depth and time was dominated by a linear trend near inertial oscillations and diurnal and semidiurnal tides each of these four elements had an rms value near 6 cm s 1 at 20 m decreasing to 2 4 cm s 1 at 250 m the vertical shear field was dominated by the diurnal tide and near inertial oscillations the semidiurnal tide and the trend had larger vertical scales of variability and consequently made smaller contributions to the shear

the sequence stratigraphy of fluvial depositional systems the role of floodplain sediment storage abstract the currently used model for alluvial sequence stratigraphy has been criticised miall 1991 and an alternative model is offered here in this model alluviation mainly takes place during transgressive and not highstand phases when accommodation space allows sediment storage the high capacity for some river systems to store floodplain sediments is a critical consideration the effects of climatic and intrinsic geomorphic changes during fluvial deposition are likely to greatly complicate simple base level controlled sequence models and recognising higher order fourth and fifth order cycles will be particularly difficult

on the possibility of a ridge current along the hawaiian islands four evenly spaced aircraft deployed expendable bathythermograph and concurrent satellite advanced very high resolution radiometer avhrr surveys were made over an extended area during a 1 year period to observe possible ridge currents along the hawaiian islands predicted or hypothesized by other investigators none of the surveys found extended currents running along the ridge instead fields of energetic eddies were found and a curious cusp shaped sea surface temperature pattern was observed in two of the avhrr fields apparent cyclonic currents around the island of hawaii were also observed we conclude that either ridge currents do not exist or that they exist but are intermittent episodic in nature or exist in a form more complicated than could be observed by this study

pennsylvanian to jurassic eolian transportation systems in the western united states peterson f 1988 pennsylvanian to jurassic eolian transportation systems in the western united states in g kocurek editor late paleozoic and mesozoic eolian deposits of the western interior of the united states sediment geol 56 207 260 the direction of sediment transport in eolian sandstones of permsylvanian to jurassic age was interpreted from crossbedding resultants vector means obtained from studies of eolian rocks in the western u s supplemented by data from the few eolian units of eastern north america these were compiled from the published or unpublished theses hterature from unpublished fidd data contributed by colleagues or from measurements made for this study in addition new paleogeographic maps were compiled to evaluate the influence of geographic features on the atmospheric circulation patterns that are inferred from the crossbedding studies regionally the crossbedding indicates northeasterly northerly or northwesterly winds present coordinates from pennsylvanian through most of middle jurassic time a rather abrupt change in wind directions occurred in late middle jurassic time late part of the cauovian age when westerly wind patterns developed by the late jurassic the winds shifted to southwesterly calculations of the consistency factor vector mean strength made from region wide analyses of the resultants indicate fairly unidirectional winds from the permsylvanian through the early jurassic middle jurassic circulation was more varied judging from crossbedding studies in the lower part of the entrada sandstone crossbedding in upper jurassic eolian rocks of wyoming and south dakota yielded a random pattern but upper jurassic rocks farther south on the colorado plateau and adjoining areas show a return to a fairly unidirectional pattern comparing the resultants with their reconstructed paleogeographic setting shows surprisingly little influence of major geographic features on overall circulation patterns however the greatest amount of local variation occurred at or near highly indented shorelines where the temperature contrast between land and water produces local wind currents that may vary appreciably from regional circulation patterns although they do not cause noticeable horizontal deflections in wind patterns small and low topographic highs appear to be able to promote the development of a dune field if a source of sand is available and if streams do not enter the growing dune field

paleopedology and paleoclimatic implications of late ordovician vertic paleosols juniata formation southern appalachians abstract claystone paleosols with abundant vertic features occur in upper ordovician ashgillian red beds of the juniata formation in the southern appalachians the beans gap claystone paleosol formed during late ordovician pedogenesis of estuarine and upper tidal flat mud deposits pedogenic processes were dominated by shrinking and swelling of clay in a subtropical to warm temperate paleolatitude 30 35 south paleoclimate characterized by a seasonal moisture deficit dry 4 8 months year large scale pedogenic slickensides are abundant and locally define pseudo anticline structures the predominance of sepic paleosol micro fabrics compares favorably with holocene vertisol micromorphology post pedogenic marine transgression resulted in erosion of the upper parts of paleosols followed by marine bioturbation and introduction of marine fluids changes in whole rock chemistry associated with early marine diagenesis include elevated na2o cao mgo mno and p2o5 in the preserved top of each paleosol reduction of fe3 to fe2 resulted in a decrease in fe2o3 and formation of drab halos around burrows the original smectitic mineralogy was converted to a well ordered 2m1 illite through progressive burial diagenesis

fluvial responses to climate and sea level change a review and look forward summary fluvial landforms and deposits provide one of the most readily studied quaternary continental records and alluvial strata represent an important component in most ancient continental interior and continental margin successions moreover studies of the long term dynamics of fluvial systems and their responses to external or allogenic controls can play important roles in research concerning both global change and sequence stratigraphy as well as in studies of the dynamic interactions between tectonic activity and surface processes these themes were energized in the final decades of the twentieth century and may become increasingly important in the first decades of this millennium this review paper provides a historical perspective on the development of ideas in the fields of geomorphology quaternary geology vs sedimentary geology and then summarizes key processes that operate to produce alluvial stratigraphic records over time scales of 103 106 years of particular interest are changes in discharge regimes sediment supply and sediment storage en route from source terrains to sedimentary basins as well as changes in sea level and the concept of accommodation late quaternary stratigraphic records from the loire france mississippi usa colorado texas usa and rhine meuse the netherlands rivers are used to illustrate the influences of climate change on continental interior rivers as well as the influence of interacting climate and sea level change on continental margin systems the paper concludes with a look forward to a bright future for studies of fluvial response to climate and sea level change at present empirical field based research on fluvial response to climate and sea level change lags behind a the global change community s understanding of the magnitude and frequency of climate and sea level change b the sequence stratigraphic community s desire to interpret climate and especially sea level change as forcing mechanisms and c the modelling community s ability to generate numerical and physical models of surface processes and their stratigraphic results a major challenge for the future is to catch up which will require the development of more detailed and sophisticated quaternary stratigraphic sedimentological and geochronological frameworks in a variety of continental interior and continental margin settings there is a particular need for studies that seek to document fluvial responses to allogenic forcing over both shorter 102 103 years and longer 104 106 years time scales than has commonly been the case to date as well as in larger river systems from source to sink studies of quaternary systems in depositional basin settings are especially critical because they can provide realistic analogues for interpretation of the pre quaternary rock record

possible climate variability in the lower old red sandstone conigar pit sandstone member early devonian south wales uk abstract the early devonian conigar pit sandstone member cpsm of the freshwater west formation lower old red sandstone lochkovian age at freshwater west in south wales comprises a heterolithic predominantly alluvial suite mudstones fine to coarse grained sandstones conglomerates with varying depositional architecture a number of discrete facies associations are observed the fine grained inclined and non inclined heterolithic association is dominant within the cpsm it represents dryland sinuous channelized flow ihs bedsets and unconfined flow non inclined bedsets at terminal and intermediate floodouts deposited under semi arid conditions mudstones were deposited in two distinct environments associated with this semi arid river system laminated and burrowed reddish brown mudstones were deposited in shallow semi permanent lakes or pools on the floodplain massive mudstones were deposited as within channel muddy braid bars with sedimentary structures being lost during subsequent compaction the mudstones exhibit vertisol pedogenesis reflecting the seasonal wetting and drying associated with the semi arid climate periods of intense desiccation are indicated by deep desiccation cracks and associated rubbly surfaces possible though unproven tidal conditions influenced a small percentage of the heterolithic channels at freshwater west the extent of these channels is uncertain the coarser grained multi storey sandstone association was deposited by low sinuosity rivers with a fluctuating but perennial discharge associated with these laterally extensive sandbodies was a high water table with surface ponding wetlands that enabled the preservation of plant detritus during high discharge events flow expanded over the contemporaneous floodplain depositing the sheet sandstone association within splay complexes the interpretation that perennial discharge may have been triggered by basin wide climate change challenges the long held view that the lower ors climate was continuously semi arid in nature the spatial temporal extent of this climate change is uncertain as it is possible that the multi storey sandbodies were deposited by allogenic rivers draining a distant possibly uplifted source area a decrease in the observed frequency and maturity of vertisol profiles and a corresponding increase in multi storey sandbodies upward through the succession may reflect a long term episodic pattern of climate change

transgressive wave ravinement on an epicontinental shelf as recorded by an upper pennsylvanian soil nodule conglomerate sandstone unit kansas and oklahoma u s a abstract a thin 3 25 cm persistent conglomerate sandstone unit occurs at the base of the transgressive systems tract of an upper pennsylvanian cyclothem below a transgressive limestone in outcrop and subsurface in se kansas and ne oklahoma it has an erosional base and a sharp top and is composed of calcitic clasts some shell fragments and quartz sand and rare coal fragments clasts are rounded equant to elongate coarse sand to pebble sized and moderately to well sorted they are micritic to microsparitic or radial fibrous calcite grains and pisoids micritic and microsparitic clasts are heterogeneous and contain rounded to elongate moulds and radiating or concentric spar or micrite filled cracks pisoids have micrite cores and superficial calcite or clay rims the clasts have similar texture and composition to the calcitic nodules and rhizoconcretions in underlying paleosols and thus were probably derived from these soil nodules upper shoreface erosion during shoreline transgression excavated the underlying paleosols and eroded coeval transgressive deposits landwards of the shoreline the eroded sediments were then reworked and transported to the lower shoreface and inner shelf by storm return flows to be deposited as a soil nodule conglomerate sandstone unit its base is an amalgamated surface of wave ravinement and initial transgression as well as the lower sequence boundary the widespread conglomerate sandstone unit suggests extensive transgressive wave ravinement on an epicontinental shelf the transgressive record composed of upward deepening dominantly fine grained lithofacies defines a new type t c4 of transgressive record which is composed of mixed carbonate and siliciclastic lithofacies with a simple transgressive lag on a low relief shelf

distinguishing climate in the soil record using chemical trends in a vertisol climosequence from the texas coast prairie and application to interpreting paleozoic paleosols in the appalachian basin u s a a suite of vertisols clay rich soils with high shrink swell potential were examined across a climosequence climatic transect in twelve soil pits from the coast prairie of texas in order to determine if mean annual precipitation map exerts a control on the chemistry of these soils and if the observed chemical trends are useful for interpreting paleoclimate records of paleovertisols in the geologic record the precipitation regime of the climosequence spans a range between 144 and 86 cm year with moisture regimes classified as udic udic ustic ustic and aridic ustic in a general northeast to southwest direction other soil forming factors such as soil age 35 40 ka parent material fluviodeltaic beaumont formation of late pleistocene age landscape low relief coastal plain and vegetation prairie or mixed woody shrubs are relatively constant across the climosequence climate sensitive chemical proxies of map identified include dithionite citrate extractable fe fedith acid oxalate extractable fe feoxal caco3 equivalent caco3equiv s and ammonium acetate extractable na k and mg naacet kacet and mgacet respectively which vary across the climosequence because of differences in effective depths of leaching and intensity of wetting and drying cycles these standard usda wet chemical climate proxies are related to bulk oxide or element chemistry of soils and paleosols measured using xrf which supports the use of geochemical climate proxies for interpreting the paleoclimate records of paleovertisols application of the chemical index of alteration minus potash cia k geochemical climofunction to late mississippian paleosols from the appalachian basin of the eastern u s demonstrates evidence for a shift from a lower to a higher map paleoclimate that is consistent with previous paleoclimate models and with observed morphological changes in the paleosols we advocate actualistic research using bulk chemistry of soils and paleosols as a means of obtaining soil information useful for interpreting paleosols in the geological record

virgilian upper pennsylvanian paleosols in the upper lawrence formation douglas group and its snyderville shale member oread formation shawnee group of the northern midcontinent usa pedologic contrasts in a cyclothem sequence abstract paleosols in the upper lawrence formation and in the snyderville shale member virgilian extend over an estimated area of over 14 000 km2 in nebraska iowa missouri and kansas these paleosols both within cyclothems are 1 critical indicators of nearly basin wide emergence peak regression of the midcontinent seaway and geomorphic stability and 2 useful stratigraphic markers both paleosols appear to be analogous to modern vertisols they have nested synformal antiformal sets 4 10 m wide of very large intersecting slickensides also some profiles of the upper lawrence paleosol also have filled cracks extending to depths of 100 cm there are however significant differences between the paleosols high chrom coloration strong preserved soil structure and small iron oxide nodules upper lawrence versus dominantly low chroma coloration weak to very weak preserved soil structure and pyrite segregations snyderville after a period of widespread subaerial exposure each paleosol was drowned and slightly eroded by a marine transgression the upper lawrence shows a single paleosol across the study area the paleosol is thickest and best developed shelfward northward and shows topohydrosequence variation at two basinward localities in northeastern kansas stratigraphic trends suggest an appreciable time differential in the south to north migration of the toronto transgression the snyderville shows two welded paleosols in southeastern nebraska and a single one elsewhere in the study area elsewhere in the snyderville there is local evidence for lowstand incision of streams and small lows that underwent little or no subaerial exposure snyderville paleogeography and pedogenesis however were markedly different from upper lawrence paleogeography and pedogenesis contrasts between the two paleosols are likely to be rel ted to intercycle changes in geomorphic conditions driven by patterns of sedimentation eustasy and tectonics and climate

goethite calcite and organic matter from permian and triassic soils carbon isotopes and co2 concentrations abstract pedogenic goethites in each of two early permian paleosols appear to record mixing of two isotopically distinct co2 components atmospheric co2 and co2 from in situ oxidation of organic matter the 13c values measured for the fe co3 oh component in solid solution in these permian goethites are 13 5 for the lower leonardian 283 ma bp paleosol mcgoeth and 13 9 for the upper leonardian 270 ma bp paleosol sap these goethites contain the most 13c rich fe co3 oh measured to date for pedogenic goethites crystallized in soils exhibiting mixing of the two aforementioned co2 components 13c measured for 43 organic matter samples in the lower leonardian waggoner ranch fm has an average value of 20 3 1 1 1s the average value yields a calculated early permian atmospheric p co 2 value of about 1 pal but the scatter in the measured 13c values of organic matter permits a calculated maximum p co 2 of 11 pal pal present atmospheric level measured values of the mole fraction of fe co3 oh in mcgoeth and sap correspond to soil co2 concentrations in the early permian paleosol profiles of 54 000 and 50 000 ppmv respectively such high soil co2 concentrations are similar to modern soils in warm wet environments the average 13c values of pedogenic calcite from 9 paleosol profiles stratigraphically associated with mcgoeth waggoner ranch fm range from 6 5 to 4 4 with a mean 13c value for all profiles of 5 4 thus the value of 13c between the pedogenic calcite data set and mcgoeth is 8 1 0 9 which is in reasonable accord with the value of 7 7 expected if atmospheric p co 2 and organic matter 13c values were the same for both paleosol types furthermore the atmospheric p co 2 calculated for the early permian from the average measured carbon isotopic compositions of the paleosol calcite and organic matter is also analytically indistinguishable from 1 pal with a maximum calculated atmospheric p co 2 permitted by one standard deviation of the organic matter 13c value of 5 pal if however measured average 13c values of the plant organic matter are more positive than the original soil organic matter as a result of diagenetic loss of 13c depleted labile organic compounds calculated permian atmospheric p co 2 using these 13c enriched organic values would underestimate the actual atmospheric p co 2 using either goethite or calcite this is the first stratigraphically constrained intrabasinal study to compare ancient atmospheric co2 concentrations calculated from pedogenic goethite and calcite these results demonstrate that the two different proxies record the same information about atmospheric co2 the fe co3 oh component in pedogenic goethite from a triassic paleosol in utah is significantly enriched in 13c relative to fe co3 oh in goethites from soils in which there are mixtures of two isotopic co2 components field relationships and the 13c value 1 9 of the triassic goethite indicate that this ancient paleosol profile experienced mixing of three isotopically distinct co2 components at the time of goethite crystallization the three components were probably atmospheric co2 co2 from in situ oxidation of organic matter and co2 from in situ dissolution of preexisting calcite although mixing of three isotopically distinct co2 components as recorded by fe co3 oh in goethite has been described in modern soil this is the first example from a documented paleosol its preservation affirms the need for careful case by case assessment of ancient paleosols to establish that goethite in any particular soil is likely to be a valid proxy of atmospheric p co 2