late paleozoic glacial episodes in gondwanaland reflected in transgressive regressive depositional sequences in euramerica the late paleozoic glaciation of gondwanaland comprised two short episodes in the famennian i and visean ii confined to brazil and adjacent northwest africa and a long episode that started in the namurian iiia of eastern australia and bolivia argentina expanded to cover much of gondwanaland in the stephanian asselian iiib and collapsed in the early sakmarian iiic dropstones in eastern australia indicate that small ice centers lingered to the kazanian across the belt of low latitudes north of gondwanaland short ranging fossils in widespread shallow marine and paralic deposits indicate synchronous deposition of transgressive regressive sequences in different parts of euramerica these sequences correlate with glacial events in gondwanaland at three levels a four major regressions in euramerica in the famennian 1 visean 2 namurian 3 stephanian 4 and the tastubian transgression that preceded the sterlitamakian regression 5 also recorded in gondwanaland correlate with glacial episodes i ii and iiia iiib and iiic b the time interval of cyclothemic deposition in euramerica brigantian or latest visean to sterlitamakian correlates with that of glacial episode iii and c the dominant period of the euramerican cyclothems as estimated from the middle and late pennsylvanian deposits of the mid continent of north america and of the thickest known gondwanaland glacigenic sediment the earliest permian lyons group of western australia is 0 4 ma equivalent in turn to the long orbital eccentricity period of the quaternary ice age and the dominant period of fluctuation of the late miocene antarctic ice cap the three levels of correlations confirm wanless and shepard9s 1936 hypothesis that the late paleozoic cyclothems are controlled largely by sea level fluctuations related to the gondwanaland glaciation

inverse relation between ice extent and the late paleozoic glacial record of gondwana the late carboniferous earliest permian age estimate 300 280 ma for maximum ice volume during late paleozoic glaciation of gondwana is challenged past estimates assume a direct relation between extent of depositional glacial record and former ice cover this assumption cannot be sustained given that the glacial record is composed predominantly of glacially influenced marine strata that accumulated on the margins of ice covered areas we argue that gondwana ice cover expanded in the early carboniferous in response to polar position availability of moisture from a mediterranean sea and epeirogenic uplift of the gondwana interior in namurian time ca 325 ma gondwana ice cover attained a maximum extent of about 21 10 6 km 2 nearly the area of maximum pleistocene ice cover despite extensive ice cover the depositional record is meager continental glacial deposits are poorly preserved on a regional unconformity thereafter extensional subsidence of intracratonic basins promoted marine flooding fragmentation of the ice cover and the accumulation of thick glacially influenced marine deposits in stephanian asselian time ca 285 ma ice cover had decreased to about 15 10 6 km 2 but glacial marine strata were being deposited and preserved across a very large area of the gondwana supercontinent

coelobiontic communities in neptunian fissures of synsedimentary tectonic origin in permian reef southern urals russia sedimentary dykes in the permian reef complexes of the russian platform are well preserved and important in providing information about reef growth the reef biota and particularly cavity dwelling organisms and sediment sources two main fissure assemblages are recognized with n80 and n170 late asselian early sakmarian and n130 140 and n60 sakmarian artinskian orientations these contemporaneous orthogonal dyke sets present orientations corresponding to the regional tectonic fabric and a tectonic origin for fracturing associated with the foreland basin development the largest dykes record eight lithofacies and several stages of fracture opening stromatoids and centimetre thick deposits of peloidal grainstones packstones thromboids which form in situ within microbial laminae on the fissure walls preceded filling by skeletal and terrigenous sediments the fissures contain a well preserved biota similar to the lower permian cavity dwelling organisms observed within the reef the coelobiontic habitat was episodically enlarged by successive synsedimentary fracturing episodes reflecting several phases of encrustation and infill of recurrent lithofacies the pioneer microbialites grew when nothing else was deposited in the fissures immediately after fracturing gastropods and ostracods occur as dense clusters probably indicating in situ growth or are considered as reworked material from the subsurface others organisms such as crinoids bryozoans tubiphytes conodonts brachiopods ammonoids and spiculate sponges are also found within fractures as reworked shells and skeletons indicating that they were washed in from the overlying sea floor the biota in the dykes is mainly represented by the dweller guilds living on the reef surface whereas members of the binding and frame building guilds are poorly represented the dykes formed during reef development and the last stage of argillaceous wackestone sedimentation within the fractures is related to a major flooding event corresponding to upper artinskian drowning of the russian platform biostratigraphically significant fossils in the dykes date the ages of the host rock and of the fissure formation and filling from late asselian to upper artinskian the tratau reef thus provides an instructive example of the interaction between carbonate accumulation and tectonic events

glaciation aridification and carbon sequestration in the permo carboniferous the isotopic record from low latitudes to evaluate the isotopic record of climate change and carbon sequestration in the late paleozoic we have compiled new and published oxygen and carbon isotopic measurements of more than 2000 brachiopod shells from carboniferous through middle permian 359 260 ma strata we focus on the isotopic records from the u s midcontinent and the russian platform because these two regions provide well preserved marine fossils spanning a broad time interval both regions show a 18o increase at the mid carboniferous boundary ca 318 ma that roughly correlates with geologic evidence for an expansion of gondwanan glaciers only the russian platform record shows a 18o maximum during the glacial maximum in the asselian in contrast to a previous study korte c jasper t kozur h w and veizer j 2005 18o and 13c of permian brachiopods a record of seawater evolution and continental glaciation palaeogeogr palaeoclimatol palaeoecol 224 333 351 our data show no oxygen isotope evidence for glacial retreat in the early permian but instead show increasing 18o values related to aridification dissimilarity in the 18o trends for the epicontinental seas of north american and the russian platform suggests that at least one region experienced periodic restriction that altered regional salinities and seawater 18o values these results highlight the need for complementary proxies to identify restricted circulation in epicontinental seas carbon isotopic compositions of carbonates exhibit substantial regional variation with low values in western north america intermediate values in the midcontinent and high values in the sverdrup basin russian platform and northern spain nevertheless both u s midcontinent and russian platform records show a late serpukhovian minimum a sharp increase across the mid carboniferous boundary and a minimum centered on the kasimovian the correlative increase in brachiopod 13c and 18o values at the mid carboniferous boundary is our best isotopic evidence for a link between the carbon burial and glaciation in the permo carboniferous

the pennsylvanian permian transition in the low latitude carbonate record and the onset of major gondwanan glaciation abstract recent studies suggest a marked expansion of glacial ice across much of gondwana beginning in the earliest permian because expansion of glacial ice results in a lowering of sea level the imprint of ice expansion should be evident worldwide as significant exposure event hiatuses or other evidence for sea level drop at or near the pennsylvanian permian boundary this literature review investigates the signature of an early permian expansion of gondwanan ice through examination of stratigraphic records from eight carbonate dominated palaeotropical regions across pangaea tropical carbonate environments are used because most form in tectonically quiescent regions and are sensitive indicators of eustatic change correlation between stratigraphic sections is achieved using the most current biostratigraphic and absolute time constraints available all studied sections show a sequence boundary or basinward shift in facies at or near the pennsylvanian permian boundary supporting the hypothesis of a significant expansion of glacial ice and global eustatic lowstand beginning in the early permian by contrast a series of mid sakmarian kungurian transgression events in the palaeotropics are interpreted to reflect the asynchronous deglaciation of gondwana the stratigraphic framework developed herein will allow for better correlations among stratigraphic records from gondwana and northern pangaea which will ultimately improve the understanding of how carbonate systems respond to global icehouse conditions such as during the late palaeozoic

correlation of upper carboniferous pennsylvanian and lower permian cisuralian marine deposits of the peri tethys abstract using available published data and our own unpublished materials a correlation is proposed of marine pennsylvanian middle and upper carboniferous and cisuralian lower permian deposits of some important regions where new data have been collected and or a new interpretation of existing data that were previously not included in the peri tethys stratigraphic correlation program has been given special emphasis was laid on the correlation within the pre caspian region most of the suggested correlations are based on fusulinid biostratigraphy magnetostratigraphic data are used to provide a precise correlation between marine and continental strata in southern urals donets basin central asia and northern caucasus

u pb dates of paleosols constraints on late paleozoic cycle durations and boundary ages u pb ages of paleosol samples from cyclothemic sections in the sacramento mountains of new mexico and the permian basin of west texas bracket the pennsylvanian permian and carboniferous permian boundaries linear interpolation and extrapolation to boundaries are accomplished by using cyclothems as periodic subdivisions the carboniferous permian boundary is 301 2 ma 2 the pennsylvanian permian boundary is 302 2 4 2 and the missourian virgilian boundary is 307 3 ma 2 these ages are within the uncertainties of recent estimates for the boundaries but are significantly more precise the average cycle duration for this upper pennsylvanian and lower permian interval is 143 64 ka 2 within the uncertainty of the 100 k y cycle that dominated pleistocene sea level history this new estimate which is much shorter than those published previously suggests that the pennsylvanian and early permian cyclothems may have been driven in a manner similar to that which caused glacio eustatic cycles of the pleistocene

late paleozoic depositional sequences are synchronous and worldwide more than fifty transgressive regressive depositional sequences are present in carboniferous and permian shallow marine successions on stable cratonic shelves worldwide these were synchronous depositional events resulting from eustatic sea level changes that generally ranged from 100 to 200 m each transgressive regressive sequence is correlatable using current fossil knowledge they average about 2 m y and range from 1 2 to 4 m y in length the presence within these strata of numerous synchronous unconformities of considerable duration and worldwide extent suggests that the fossil record is very incomplete and that we are studying a punctuated fossil record and not a punctuated evolution based on a highly irregular mutation rate these late paleozoic transgressive regressive depositional sequences facilitate correlations because depositional histories of a rock succession can support interpretations of faunal assemblages and faunal similarities in evaluating age relationships

sea level curve for pennsylvanian eustatic marine transgressive regressive depositional cycles along midcontinent outcrop belt north america at least 55 cycles of marine inundation and withdrawal are recognized in the mid desmoinesian to mid virgilian midcontinent outcrop sequence in north america they range from widespread major cycles classic cyclothems with deep water facies extending across the northern shelf through intermediate cycles persisting as marine horizons across the shelf to minor cycles developed on the lower shelf or as parts of major cycles biostratigraphic differentiation of the cycles should establish interbasinal correlation on a scale fine enough to allow evaluation of differential tectonics and sedimentation sequential groupings of cycles are more irregular than proposed megacyclothems or mesothems but they may be obscured by the distinctness of the major cyclothems estimates of cycle periods range from about 40 to 120 x 10 sup 3 yr for the minor cycles up to about 235 to 400 x 10 sup 3 yr for the major cyclothems the range for all cycles corresponds well to the range of periods of earth s orbital parameters that constitute the milankovitch insolation theory for the pleistocene ice ages and it further supports gondwanan glacial control for the pennsylvanian cycles even though the dominant period of the major pennsylvanian cyclothems is up to four times longer than the dominant 100 000 yr period inmore the pleistocene the shapes of both curves display rapid marine transgression rapid melting of ice caps and slow interrupted regression slow buildup of ice caps which suggest similar linkages between the climatic effects of the orbital parameters and ice cap formation and melting at the two different scales widely separated in time 28 references 3 figures less

permian palaeogeographic evolution of the jiangnan basin south china abstract the most striking geographic feature of the permian of south china is the jiangnan basin which intimately reflects the interplay between the yangtze and cathaysia blocks geographic and sedimentological evolution suggests that the jiangnan basin superposed on a precambrian collisonial megasuture and a folded early paleozoic deep basin was an extensional intracratonic basin it opened in the longlinian and became more passive and restricted in the latest maokouan the remarkably similar geographic patterns of the jiangnan basin in the early and late palaeozoic suggest that the yangtze and cathaysia blocks were coherent during the paleozoic

late palaeozoic evolution of the north atlantic margin of pangea abstract eleven palaeogeographic maps spanning the earliest carboniferous tournaisian to late permian kazanian have been constructed for the northern north atlantic based on available onshore and offshore data each palaeogeographic map corresponds to an epoch i e 4 17 ma there are no reconstructions of the serpukhovian and tatarian and the kungurian ufimian are treated as one the palaeogeographic reconstructions outline a change in the overall depositional environment of the barents sea north greenland area from huge humid flood plains in the early carboniferous over shallow warm seas in the mid carboniferous to mid permian to cooler and possibly deeper marine environments in the late permian in east greenland non marine conditions occurred during the entire carboniferous and following a prolonged early permian hiatus warm water carbonates were deposited during the late permian the changes reflect large scale shifts in palaeoclimatic and subsidence patterns related to the northward drift of the area and ongoing rifting in the region

orbital forcing of global change throughout the phanerozoic a possible stratigraphic solution to the eccentricity phase problem astronomers have little confidence in orbital forcing calculations on time scales beyond ten million years they are confident that the fundamental frequencies of the planetary orbits remain nearly constant on time scales of hundreds of millions of years small variations in these frequencies and chaotic behavior of certain resonance relationships however can introduce large uncertainty regarding the exact orientation of planetary orbits on time scales of tens to hundreds of millions of years we introduce a simple trigonometric series expression for eccentricity in order to evaluate effects that arise from imposing specified displacements in orientation of planetary orbits the resulting changes in the character of the calculated eccentricity time series should be a guide to stratigraphers seeking to relate orbital forcing to stratigraphic time series throughout the phanerozoic this geologic calibration of eccentricity time series in relatively old stratigraphic sequences may provide astronomers with clues to further refinement of their calculations

lower permian oncolites from south china implications for equatorial sea level responses to late palaeozoic gondwanan glaciation the oncoid bearing chuanshan formation is a regionally extensive carbonate deposit of predominantly asselian to early sakmarian early permian age in south china occupying an area of some 500 000 km2 throughout south china the oncoid bearing horizons are generally stable and broadly comparable in lithology fossil content and the morphology of the oncoid grains four types of microfacies are recognized from the oncolite succession and overall they suggest a moderate to high energy wave agitated shallow marine carbonate platform environment an analysis of the stratigraphic distribution of oncoid grain size density thickness and the bedding structures of the oncolite beds and the number of coating laminae indicate the presence of metre scale cyclothems suggestive of possible high frequency cycles of sea level fluctuation compared to carbonate successions above and below that lack oncolites and in conjunction with evidence from sequence stratigraphic and isotopic geochemical analyses of coeval carbonate deposits in south china and elsewhere the origin of the chuanshan oncolites is linked to a drastic drop in global sea level at the pennsylvanian permian boundary that can be correlated closely in timing with the zenith of the late palaeozoic gondwanan glaciation it is further suggested that the eustatic changes apparent from the deposition of the chuanshan oncolites and similar coeval deposits in lower palaeolatitudes were coupled with and influenced by the contemporaneous high latitude gondwanan glaciation the largest and longest known such event in phanerozoic earth history

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

shifts in late paleozoic atmospheric circulation over western equatorial pangea insights from pedogenic mineral δ18o compositions the d 18 o values of pedogenic calcites phyllosilicates and iron oxyhydr oxides from fossil soils throughout the southwestern united states show systematic paleolatitudinal and temporal trends that indicate a significant change in soil moisture conditions and atmospheric circulation patterns over southwestern euramerica throughout latest pennsylvanian and early permian time a progressive depletion of as much as 6 in mineral 18 o values with increasing distance northward to 108 of the paleoequator indicates a weakening or disruption of zonal easterly flow over the study area by latest pennsylvanian time furthermore elevated d 18 o values suggest a proximal source of paleoprecipitation over the study area perhaps due to initiation of reversed equatorial flow over tropical southwestern euramerica coupling of the geographic and temporal trends defined by pedogenic mineral d 18 o values with those defined by climatically sensitive paleosol pedotypes in the study area along with overall elevated mineral d 18 o values provides some of the strongest evidence that northern hemisphere monsoonal circulation was well established over pangea by early permian time

from detached to attached carbonate buildup complexes 3d seismic data from the upper palaeozoic finnmark platform southwestern barents sea abstract carbonate buildups were abundant during the palaeozoic three dimensional seismic data from the finnmark platform barents sea has been used to reconstruct the evolution of laterally extensive carbonate buildup complexes in space and time the results suggest that the location of upper palaeozoic warm and cool water carbonate buildups from the finnmark platform is controlled by faults and the sea floor morphology at the time of their growth a fluctuating sea level affected the growth of the carbonate buildups but they also influenced their own environment by forming lagoons atoll like ridges and possibly areas with restricted circulation warm water carbonate buildups forming ridges and isolated mounds occur in the gipsdalen group latest serpukhovian mid sakmarian where they initially grew in a detached platform setting the carbonate buildups are several tens of kilometres long up to 2 5 km wide and 300 m thick and interpreted to consist of vertically stacked complexes of sub seismic scale carbonate buildups evaporites were deposited and later subject to karstification possibly during a period of sub aerial exposure before a transgression and the subsequent carbonate deposition and buildup growth bridged the detached platform with the attached platform in the bjarmeland group lower permian 0 35 4 8 km wide 1 5 27 km long and 60 420 m thick cool water bryozoan dominated straight sinuous and continuous carbonate ridges or atoll like ridges are located on top of the warm water carbonate structures three dimensional maps of upper palaeozoic carbonate buildups document their geomorphology distribution and size through time the lateral and vertical growth of carbonate buildups has been reconstructed revealing how their distribution changed over time and with changing environmental settings

stratigraphic architecture of lower permian cyclic carbonate reservoirs chase group in the mid continent usa based on outcrop studies seven depositional sequences each of which consists of two intermediate order cyclothems compose outcrops of the chase group permian wolfcampian in the mid continent principal reservoir analog facies are restricted mainly to the highstand systems tracts of cyclothems these facies include subtidal lime sands deposited mainly in downdip distal ramp settings and peritidal dolomudstones deposited farther updip on the ramp the stratigraphic and depositional architecture of the section was controlled by the interplay among paleobathymetry glacio eustasy and periodic syndepositional tectonism porous lime sands dominate in the lower part of the chase group the forced regressive unconformity bounded sequences within which they occur were deposited during relatively high magnitude eustatic fluctuations that resulted in marine accommodation increases great enough to preclude peritidal deposition porous peritidal facies instead dominate in the upper part of the chase group the sequences within which these normal regressive deposits are present were deposited during lower magnitude eustatic fluctuations and decreased marine accommodation which allowed for their eventual progradation across the ramp complex porosity heterogeneity is evident within individual depositional sequences and component cyclothems as well as vertically within the chase group

characterizing aftershock sequences of the recent strong earthquakes in central italy the recent strong earthquakes in central italy allow for a comparative analysis of their aftershocks from the viewpoint of the unified scaling law for earthquakes usle which generalizes the gutenberg richter relationship making use of naturally fractal distribution of earthquake sources of different size in a seismic region in particular we consider aftershocks as a sequence of avalanches in self organized system of blocks and faults of the earth lithosphere each aftershock series characterized with the distribution of the usle control parameter we found the existence in a long term of different intermittent levels of rather steady seismic activity characterized with a near constant value of which switch in mid term at times of transition associated with catastrophic events on such a transition seismic activity may follow different scenarios with inter event time scaling of different kind including constant logarithmic power law exponential rise decay or a mixture of those as observed in the case of the ongoing one associated with the three strong earthquakes in 2016 evidently our results do not support the presence of universality of seismic energy release while providing constraints on modelling seismic sequences for earthquake physicists and supplying decision makers with information for improving local seismic hazard assessments

foraminiferal zonation of late paleozoic depositional sequences from the later part of the devonian through the permian calcareous foraminifers became abundant and evolved rapidly this rapid evolution of taxa forms the basis of a detailed zonation through the carboniferous and permian comparison of this evolutionary history of foraminifers their biostratigraphic zonation and the depositional sequences in which they occur suggests that sea level events in late paleozoic depositional history contributed significantly in subdividing a fairly continuous evolutionary record into a succession of about 75 identifiable foraminiferal zones during a 100 125 myr time span although variable in terms of duration and vertical occurrences the more completely recorded high stand intervals give brief histories of the foraminiferal evolutionary record and are sandwiched between the poorly recorded or unrecorded low stand intervals many of the individual foraminiferal zones are confined to a single depositional sequence the late paleozoic carbonate foraminiferal fossil record as with the rest of the fossil record is strongly affected by sediment deposition nondeposition as a result of major changes in sea level this incomplete fossil record is the result of repeated depositional breaks because of the way that depositional sequences form it is not possible to ascribe macromutations punctuated evolution or punctuated gradualism as the cause of this evolutionary pattern of the shelf carbonate fossil record this pattern is distinctive and we refer to it as sequence evolution and sequence extinction in the later part of the middle permian and in the late permian the fossil record clearly illustrates that a series of faunal losses through sequence extinctions progressively exceeded faunal replacements and new species through sequence evolution but not a mass extinction as is commonly ascribed to the end of the permian period most permian faunas became extinct in the interval of 8 to 4 million years before the end of the late permian

coupled carbon isotopic and sedimentological records from the permian system of eastern australia reveal the response of atmospheric carbon dioxide to glacial growth and decay during the late palaeozoic ice age abstract proxy geochemical records from high latitude ice proximal deposits have the potential to provide key insights into past icehouse climates but such records are rare the permian system of eastern australia contains a rich record of environmental and climatic changes that occurred in areas proximal to glaciation during the acme and waning stages of the late palaeozoic ice age within this succession a wealth of fine grained organic matter rich facies provides an opportunity to construct a bulk 13corg record that records changes in atmospheric co2 through the permian fluctuations in 13corg track changes in climate determined independently on the basis of sedimentological criteria in the same strata these patterns are also broadly consistent with multiple proxy records derived from palaeoequatorial sites the results of this geochemical investigation 1 support recent studies using the high latitude ice proximal sedimentologic and stratigraphic record and palaeoequatorial geochemical proxies that document highly variable climatic conditions within the overall permian icehouse to greenhouse transition and 2 confirms that the sedimentary record of glaciation from eastern australia reflects global changes in atmospheric co2 on several m y order timescales

growth and demise of permian biogenic chert along northwest pangea evidence for end permian collapse of thermohaline circulation abstract the permian chert event pce was a 30 ma long episode of unusual chert accumulation along the northwest margin of pangea and possibly worldwide the onset of the pce occurred at about the sakmarian artinskian boundary in the sverdrup basin canadian arctic where it coincides with a maximum flooding event the ending of high frequency high amplitude shelf cyclicity the onset of massive biogenic chert deposition in deep water distal areas and a long term shift from warm to cool water carbonate sedimentation in shallow water proximal areas a similar and coeval shift is observed from the barents sea to the northwestern usa a landward and southward expansion of silica factories occurred during the middle and late permian at which time warm water carbonate producers disappeared completely from the northwest margin of pangea biotically impoverished and increasingly narrow cold water carbonate factories characterised by non cemented bioclasts of sponges bryozoans echinoderms and brachiopods were then progressively replaced by silica factories by late permian time little carbonate sediments accumulated in the barents sea and in the sverdrup basin where the deep to shallow water sedimentary spectrum was occupied by siliceous sponge spicules by that time biogenic silica sedimentation was common throughout the world silica factories collapsed in the late permian abruptly bringing the pce to an end in northwest pangea the end permian collapse of the pce was associated with a major transgression and with a return to much warmer oceanic and continental climatic conditions chert deposition resumed in the distal oceanic areas during the early middle triassic anisian after a 8 10 ma interruption early triassic chert gap the conditions necessary for the onset expansion and zenith of the pce were provided by the thermohaline circulation of nutrient rich cold waters along the northwestern and western margin of pangea and possibly throughout the world oceans these conditions provided an efficient transportation mechanism that constantly replenished the supply of silica in the area created a nutrient and oxygen rich environment favouring siliceous biogenic productivity established cold sea floor conditions hindering silica dissolution while increasing calcium carbonate solubility and provided conditions adverse to organic and inorganic carbonate production the northwest margin of pangea was for nearly 30 ma bathed by cold waters presumably derived from the seasonal melting of northern sea ice the assumed engine for thermohaline circulation this process started near the sakmarian artinskian boundary intensified throughout middle and late permian time and ceased suddenly in latest permian time it led to oceanic conditions much colder than normally expected from the palaeolatitudes and the influence of cold northerly derived water was felt as far south southern nevada the demise of silica factories was caused by the rapid breakdown of these conditions and the establishment of a much warmer marine environment accompanied by sluggish circulation and perhaps a reduced input of dissolved silica to the ocean complete thawing of northern sea ice would have ended thermohaline circulation and led to warm and sluggish oceanic conditions inimical to the production accumulation and preservation of biogenic silica

global time scale and regional stratigraphic reference scales of central and west europe east europe tethys south china and north america as used in the devonian carboniferous permian correlation chart 2003 dcp 2003 the boundaries of the devonian carboniferous and permian stages of the global stratigraphic reference scale abbreviated to global stratigraphic scale gss are described in relation to the biostratigraphic and or lithostratigraphic units of the regional stratigraphic reference scales abbreviated to regional stratigraphic scales rss of central and west europe east europe tethys south china eastern tethys and north america in their type regions the boundaries of gss units rarely coincide with those of homonymous rss units moreover the definitions of some rss units have changed several times over the last decades and subsequent misunderstanding of the stratigraphical significance of these changes has often introduced errors into proposed global correlation charts the stratigraphic framework proposed in our global devonian carboniferous permian correlation chart 2003 dcp 2003 devonian carboniferous permian correlation chart 2003 menning m schneider j w alekseev a s amon e o becker g von bitter p h boardman d r bogoslovskaya m braun a brocke r chernykh v chuvashov b i clayton g dusar m davydov v i dybova jachowicz s forke h c gibling m gilmour e h goretzki j grunt t a hance l heckel p h izokh n g jansen u jin y g jones p kading k ch kerp h kiersnowski h klets a klug ch korn d kossovaya o kotlyar g v kozur h w laveine j p martens th nemyrovska t l nigmadganov a l paech h j peryt t m rohn r roscher m rubidge b schiappa t a schindler e skompski s ueno k utting j vdovenko m v villa e voigt s wahlman g p wardlaw b r warrington g weddige k werneburg r weyer d wilde v winkler prins c f work d m 2004 abschlusskolloquium dfg schwerpunktprogramm 1054 evolution des systems erde wahrend des jungeren palaozoikums im spiegel der sedimentgeochemie abstracts univ erlangen germany 2004 p 43 herein abbreviated to dcp 2003 and cited as dcp 2003 in references is an attempt to reduce these errors the dcp 2003 is the stratigraphic base for project 1054 of the deutsche forschungsgemeinschaft dfg the evolution of the late palaeozoic in the light of sedimentary geochemistry this composite time scale has been carefully balanced as far as data allows to remove unnecessary artificial compression and expansion of time intervals biozonations and depositional events the ages selected in dcp 2003 are markedly different to those in the geologic time scale 1989 gts 1989 harland w b armstrong r l cox a v craig l e smith a g smith d g 1990 a geologic time scale 1989 cambridge univ press cambridge harland w b armstrong r l cox a v craig l e smith a g smith d g 1990 a geologic time scale 1989 cambridge univ press cambridge pp 1 263 and in gradstein and ogg gradstein f m ogg j 1996 a phanerozoic time scale episodes 19 1 2 3 4 insert whereas they are closer to those of the geologic time scale 2004 gts 2004 gradstein f m ogg j g smith a g 2004 a geologic time scale 2004 cambridge univ press cambridge pp 1 589 mostly the ages are rounded to the nearest 0 5 ma in order to avoid estimates of questionable accuracy whereas ages of 0 1 ma in the gts 2004 and their error bars of 0 4 ma to 2 8 ma for the devonian to permian stage boundaries suggest an improved accuracy in contrast in the dcp 2003 questionable ages and positions of stratigraphic boundaries are marked by arrows c 2006 elsevier b v all rights reserved

paleozoic evolution of southern margin of permian basin prior to late pennsylvanian time the permian basin of west texas was a part of the southern margin of the north american craton and was the site of shallow warm water carbonate deposition as the south american margin of gondwana gradually moved northwestward during late paleozoic time the oceanic floor deposits and overlying turbidite fan deposits between north america and south america became parts of large accretionary wedges of semiconsolidated sediments in a series of steps these wedges were folded and thrust toward the northwest against then finally onto the southern margin of north america these compressive steps caused the repeated piling up of the accretionary wedges to form rapidly eroding highlands on the cratonic margins repeated loading on the north american margin formed a series of elongate deep water depositional troughs fore deeps immediately north and west of the accretionary wedges and these received thick accumulations of turbidites the youngest of these deep basins include the northwestern part of the val verde basin to the north and the marfa basin to the west which received basinal deposits from within desmoinesian into early late permian time loading of the cratonic margin also resulted in renewed faulting along generally northwest to north trending older zones of weakness these zones are apparently of precambrian age on the craton the late paleozoic faults mainly had high angle to vertical fault planes and commonly had large components of horizontal displacement this fault system outlines the major uplifts and basins in the permian basin region the joining together of gondwana and euramerica across the marathon salient of the orogenic belt was essentially completed by mid wolfcampian time after that time the southern margin of the permian basin represented by the dugout and marathon allochthons and the diablo platform became a relatively stable tectonic area the glass mountains expose a series of north and northwest dipping cuestas of permian carbonate shelf and shelf edge deposits that accumulated on a platform constructed from these two allochthonous accretionary wedges these permian deposits prograded north and northwestward into the narrow hovey channel which connected the marfa basin with the southern end of the delaware basin carbonate reef growth finally restricted the inflow of marine water into the delaware basin near the end of late guadalupian time

stratigraphic imprint of the late palaeozoic ice age in eastern australia a record of alternating glacial and nonglacial climate regime stratigraphic and sedimentological data from new south wales and queensland eastern australia indicate that the late palaeozoic ice age comprised at least eight discrete glacial intervals each 1 8 ma in duration here termed glaciations separated by nonglacial intervals of comparable duration these events spanned an interval from mid carboniferous c 327 ma to the early late permian c 260 ma and illustrate a pattern of increasing climatic austerity and increasingly widespread glacial ice from initial onset until an acme in the late early permian followed by an opposite trend towards the final demise of glaciation in the late permian the alternating glacial nonglacial motif suggests that the late palaeozoic ice age was considerably more dynamic than previously thought these patterns are remarkably consistent with recent interpretations of palaeofloral change eustatic sea level fluctuations and co 2 climate glaciation relationships for this interval of time the detailed record of alternating glacial and nonglacial climate mode disclosed herein may facilitate more closely resolved evaluations of stratigraphic records elsewhere notably in far field ice distal northern hemisphere successions

the role of climate in stratigraphic patterns exhibited by late palaeozoic rocks exposed in kansas abstract late palaeozoic cyclothems of the midcontinental u s cannot be represented by a single ideal facies sequence rather they encompass a wide range of cycle types depending on their stratigraphic position the exposed late palaeozoic pennsylvanian and permian rocks of kansas as compiled by zeller 1968 can be divided into nine major lithofacies these lithofacies were ordered based on their times of greatest abundance through the section from oldest to youngest they attain their peak abundance in the following order 1 coal 2 gray mudrocks and sandstones 3 black mudrocks 4 limestones 5 cherty limestones 6 fossiliferous mudrocks 7 variegated mudrocks 8 evaporites and 9 variegated dolomitic siliciclastics climatically these nine lithofacies suggest a change from generally wetter at the base to generally drier at the top of the section this climatic trend was probably generated by a complex interaction of factors primarily driven by global tectonics climatic changes can be used to explain the five generally recognized types of lithofacies cyclothems in kansas and thus are a potential explanation for the changing stratigraphic patterns of the entire late palaeozoic time interval of kansas and perhaps elsewhere