deformation at an archean subprovince boundary northern minnesota structural analysis in the northern margin of the quetico subprovince part of the archean superior province of the canadian shield in minnesota reveals that the main deformation involved polyphase folding f1 recumbent and nappe like and f2 upright east west trending and tight to isoclinal during regional ductile transpression and amphibolite facies metamorphism a younger deformation developed during the latter stages of regional transpression resulted in the generation of localized ultraphyllonites along the steeply dipping rainy lake seine river fault rlsrf the major fault separating the quetico subprovince from the rainy lake wrench zone a wedge shaped block between the quetico and wabigoon subprovinces the transpression involved north south shortening and east west dextral shear the presence of shear zones in amphibolite facies wall rock south of the fault and in lower grade ultraphyllonites within the rlsrf suggests that localization of shear occurred by work and or reaction softe

structural evolution of archean rocks in the western wawa subprovince minnesota refolding of precleavage nappes during d2 transpression recent mapping in the western wawa subprovince the vermilion district and its westward extensions in minnesota has identified a major northeast trending stratotectonic break informally called the leech lake structural disconformity llsd that separates two contrasting terranes north of the llsd are elongate east northeast trending fault bounded panels of volcanic rocks which are mostly north topping and homoclinal south of the llsd large scale northwest trending folds involve basaltic sequences that are stratigraphically overlain by thick sections of dacitic volcaniclastic and turbiditic rocks however the most prominent outcrop scale deformational features are northeast trending vertical folds and associated axial planar cleavage related to transpression in d2 d1 minor folds and cleavage are rare new field data indicate that the large folds in a predominantly sedimentary part of the southern terrane are early formed d0 d1 and nappe like the precise form of the early folds is largely ob

analysis of kerogens of miocene shales in a homogenous sedimentary column a study of maturation using flash pyrolysis techniques and carbon 13 cp mas nmr abstract type ii iii kerogens from a sedimentary column of miocene age were studied by pyrolysis mass spectrometry pyrolysis gas chromatography and soli state carbon 13 cp mas nmr in order to follow the changes occurring in the kerogen as a result of maturation an immature kerogen was artificially matured in the laboratory and the resulting material was compared with the mature natural samples the three techniques used produced complementary information on the effect of maturation on the kerogen the simulated maturation product was qualitatively similar to the most mature natural kerogen but the temperature has apparently been too high for a quantitative identical result the py ms data showed an important increase in the abundance of simple sulphur products in the pyrolysate of the most mature samples

characterization of high molecular weight organic matter in marls of the salt iv formation of the mulhouse basin high molecular weight organic matter of six marl samples of the mulhouse basin has been characterized the kerogen asphaltene and polar fractions were analysed by flash pyrolysis gc ms in addition sulphur rich geomacromolecules present in the polar fractions were also desulphurized with raney ni and the released hydrocarbons were characterized by gc ms the kerogen and asphaltene pyrolysates are dominated by linear and isoprenoid alkanes and alkenes most likely derived from aliphatic biopolymers of algae algaenans and contain moderate to low amounts of alkylated thiophenes marls deposited under hypersaline conditions contain more organically bound sulphur and less isoprenoid algaenans in their kerogen asphaltene fractions than marls deposited under less saline conditions high contributions of terrestrial organic matter are not revealed by abundant alkyl phenols in the pyrolysates desulphurization of sulphur rich geomacromolecules present in the polar fractions yields hydrocarbons with distributions different from those of the free saturated hydrocarbons but the amounts released are low relative to the hydrocarbons present as such

a preliminary investigation of the optical properties of asphaltene and their application to source rock evaluation organic petrological methods have been used to investigate optical properties of asphaltenes from source rocks humic coals and crude oils with respect to microscopic structure fluorescence and reflectance asphaltenes form a distinctive group all asphaltenes exhibit brown fluorescence with relative intensity ranging from 0 15 to 0 35 the intensity decreasing gradually with increasing maturity of the source rocks from which the asphaltene is extracted asphaltene reflectance is an important geochemical parameter the reflectance of asphaltenes in air medium ra varies in the range of 4 5 8 0 and is affected mainly by source rock type and maturity in general the richer the hydrogen content of a kerogen the weaker the reflectance of its derived asphaltenes the contribution of source matter type to the variation of asphaltene reflectance can be as much as 0 50 ra in the low maturity range there is a nearly linear relationship between asphaltene reflectance and vitrinite reflectance in oil ro and geochemical maturity indicators such as cpi mpr and mpi asphaltene reflectance is a potentially valuable technique for the maturity determination of source rocks and crude oils

the dynamics of the extratropical response to madden julian oscillation convection the rossby wave source rws and the corresponding extratropical wave response to tropical convection associated with different phases of the madden julian oscillation mjo is investigated with the dynamical core of a climate model the initial flow is specified to correspond to the boreal winter climatological flow and an imposed tropical heating that is derived from the observed precipitation for all eight mjo phases one key question addressed here is why does the extratropical rossby wave train depart the subtropics at a longitude well to the east of the rws for all eight mjo phases it is found that the extratropical response over the north pacific and north america is almost entirely due to the mjo convection over the western tropical pacific the rws is excited within the first 24 h after the model heating is turned on for mjo phases 1 3 and 8 the rws leads to the development of a cyclonic anomaly over southeast asia via advection of the climatological absolute vorticity by the anomalous divergent wind in the subtropics and by horizontal convergence in the tropics mjo phases 4 7 show opposite features the resulting anomaly is then advected eastward by the climatological zonal wind toward the central pacific after which dispersion into the extratropics and the excitation of a pacific north american teleconnection pattern takes place

on the genesis of archean granite through two stage melting of the quetico accretionary prism at a transpressional plate boundary regional geologic relationships and geochemical data support the idea that late stage biotite granite of the lac la croix type may have formed by partial melting of previously migmatized metasedimentary rocks in the quetico subprovince of the superior craton the proposed parent material is an intimately layered rock composed of approximately half to two thirds biotite schist and half to one third granitoid leucosome the bulk chemical attributes of such a material were estimated from detailed mapping and drilling of two large outcrops near pearl lake minnesota previous work has demonstrated that the granitoid leucosome of the layered migmatite is the intrusively injected product of partial melting of a metasedimentary protolith therefore the proposed derivation of the younger lac la croix type granite from layered migmatite in effect represents a second distillation of granitic liquid from meta sedimentary rocks that had been enriched ingranitic components in the first cycle of partial melting and melt migration it is postulated that the implied two stage melting of metasedimentary rocks was related to thermal consequences within the quetico accretionary complex as tectonism along the quetico wabigoon boundary alternated between subduction and transform kinematics during late archean time

an evaluation of criteria to deduce the sense of movement in sheared rocks some of the most useful criteria for the deduction of the sense of shear are summarized for use in areas where unequivocal field evidence is lacking apparently conflicting evidence from rotated pressure shadow regions around porphyroclasts and porphyroblasts is clarified the use of quartz crystallographic fabric asymmetry to deduce the shear sense in the bulk rock should be treated with caution and used only together with detailed microstructural observations

petrogenesis of the dog lake granite chain quetico basin superior province canada implications for neoarchean crustal growth abstract the neoarchean dog lake granite chain consists of six intrusions shabaqua silver falls trout lake barnum lake white lily and penassen lake which parallel the tectonic boundary between the abitibi wawa terrane to the south and the quetico basin to the north it is a single composite body at depth with derivative branches extending higher into the crust and consists of three phases monzodiorite syenite quartz monzonite and granite emplaced at approximately 2 671 ga 2 663 2 669 ga and 2 670 ga respectively the metaluminous monzodiorites with abundant angular igneous mafic xenoliths enriched zircon hf t values ranging from 0 52 to 4 20 and enriched nd t 0 37 to 1 74 were generated by assimilation fractional crystallization of a mafic magma generated by partial melting of enriched mantle metasomatized by melts of subducted oceanic sediments the metaluminous syenite quartz monzonite phase has similar mineral assemblages trace element and nd hf isotopic characteristics to the monzodiorite and was probably produced by assimilation fractional crystallization of a monzodiorite magma the granite hosted zircons have prominent positive ce anomalies negative eu anomalies and mostly positive zircon hf t 0 12 to 4 25 and enriched nd t values 1 70 to 0 71 suggesting a mixed source of immature sedimentary rocks and metasomatically enriched mantle derived magma the subduction of oceanic lithosphere under the abitibi wawa arc during the collision of the abitibi wawa arc and the wabigoon terrane before 2 7 ga generated a metasomatically enriched mantle and associated volcanic rocks the volcanic rocks underwent rapid weathering and erosion to form the immature sedimentary rocks of the quetico accretionary prism lithospheric inversion caused partial melting of the metasomatically enriched mantle generating a mafic magma the mafic magma ascended and underwent assimilation fractional crystallization forming the monzodiorite and syenite quartz monzonite mafic magma was emplaced at the base of the archean immature sedimentary rocks triggering melting to generate felsic magma mixing of these felsic and mafic magmas generated the dlgc granite in the shallow crust the neoarchean arc continent collision preserved in the quetico basin is similar to that in modern arc systems where intra oceanic arc crust is added to continental margins suggesting it was an important mechanism for recycling juvenile crust generating compositional differentiation and cratonization

observed connection between stratospheric sudden warmings and the madden julian oscillation 1 the effect of the madden julian oscillation mjo on the northern hemisphere wintertime stratospheric polar vortex and major mid winter stratospheric sudden warmings ssws is evaluated using a meteorological reanalysis dataset the mjo influences the region in the tropospheric north pacific sector that is most strongly associated with a ssw consistent with this ssws in the reanalysis record have tended to follow certain mjo phases the magnitude of the influence of the mjo on the vortex is comparable to that associated with the quasi biennial oscillation and el nino the mjo could be used to improve intra seasonal projections of the northern hemisphere high latitude circulation and in particular of the tropospheric northern annular mode at lags exceeding one month

biodegradation of tar sand bitumens from the ardmore anadarko basins oklahoma ii correlation of oils tar sands and source rocks abstract in an earlier paper we reported the effects of biodegradation on tar sand bitumens from the southern part of the ardmore and anadarko basins in this paper we wish to describe geochemical correlations that have been made between the tar sand bitumens and oils produced from various formations in the pauls valley area 25 miles to the north it was determined that the tar sands were formed from a source similar to many of these oils whose reservoir ages ranged from ordovician to pennsylvanian the oils had been previously divided into two major groups on the basis of their biomarker distributions with one group 80 of the oils studied proposed to have been sourced from the woodford shale devonian and the other group from the viola limestone ordovician the tar sand bitumen oil correlation study based on hydrocarbon and porphyrin biomarker distributions and pyrolysis gas chromatography of asphaltenes has shown that the tar sand bitumen appears to be genetically related to the group of oils derived from the woodford shale and more specifically to those present in the oil creek formation ordovician of the anadarko basin

new insights into archean crustal development from geochronology in the rainy lake area superior province canada precise isotopic analyses of zircon titanite and rutile from units in the rainy lake area of northwest ontario are combined with structural investigations to develop new stratigraphic interpretations in which lithotectonic sequences were juxtaposed by thrusting prior to steepening by wrenching ages for the oldest volcanic and plutonic rocks in the area range from 2725 pm 2 ma to 2728 4 3 ma the age of metagray wackes of the coutchiching group is bracketed between 2704 pm 3 ma and 2692 pm 2 ma by detrital zircon and a crosscutting intrusion alluvial conglomerate of the seine group is bracketed between 2696 5 3 ma the age of a clast and 2686 2 1 ma the age of the undeformed ottertail lake pluton the coutchiching group is younger than structurally overlying metavolcanic rocks and is therefore allochthon ous these data suggest that sedimentation and deformation were controlled by collisional plate interactions and subsequent transpression at the subprovince boundary combined with dat

stratigraphy structure and lode gold system at the central manitoba mine trend rice lake greenstone belt archean superior province manitoba canada abstract the central manitoba mine trend is one of the most important lode gold districts in the rice lake greenstone granitoid belt of the western uchi subprovince within western superior province manitoba canada neoarchean host rocks consist of a south facing metavolcano sedimentary succession 2 75 2 73 ga intruded by voluminous gabbroic sills and tonalitic granodioritic plutons 2 73 2 72 ga as well as late aplite dikes 2 73 2 72 ga and quartz feldspar porphyry dikes 2 73 2 71 ga five generations g1 g5 of deformation structures have been recognized through detailed geological mapping the entire succession was folded during g1 and g2 prior to rare late aplite dike emplacement all fault fill veins and extension veins cut all lithologic units and are structurally governed by late g3 and g4 conjugate shear zones main gold mineralization occurs within fault fill veins hosted by west trending steeply dipping g4 dextral brittle ductile and ductile shear zones which occur along or across contacts of metabasalt metagreywacke and metagabbro or entirely within metagabbro microstructural and paragenetic analyses on main gold bearing veins have revealed that gold is intimately associated with quartz pyrrhotite and tellurobismuthite main gold introduction is interpreted to have taken place contemporaneously with pyrrhotite and tellurobismuthite deposition early during g4 shearing these results in structural and mineralogical aspects at the central manitoba mine trend provide new constraints on structural evolution and gold mineralization of the southeastern rice lake belt and can be used to improve exploration models for gold deposits in archean terranes

isoprenoid constituents in kerogens as a function of depositional environment and catagenesis abstract the ratio of the abundance of the c 19 1 isoprenoids 1 pristene and 2 pristene to the abundance of n c 17 1 n c 17 0 is significantly lower in pyrolysates of kerogens from highly anoxic depositional environments than in pyrolysates of kerogen if similar types and levels of catagenesis from more oxic organic facies 13 c nmr analysis shows that the occurrence of lower relative concentrations of isoprenoid precursors also correlates with the occurrence of low proportions of oxygen bonded carbon and high proportion of aliphatic carbon in kerogens the ratio of 1 pristene to n c 17 1 n c 17 0 can be correlated laterally and statigraphically within a basin there is no clearly discernible dependence of relative isoprenoid concentration of kerogen type for oil generative kerogens although immature lignites have high 1 pristene n c 17 1 n c 17 0 ratios the 1 pristene n c 17 1 n c 17 0 ratios in kerogens pyrolysates from the same organic facies decrease logarithmically with increasing catagenesis and can be correlated directly with measured vitrinite reflectance values geologic and experimental data imply that 1 pristene precursors are lost from kerogen more rapidly than the precursors of the c 18 isoprenoid the lower relative isoprenoid concentrations observed in anoxically deposited kerogens appear to be the result of the enhanced preservation of normal alkyl groups and the enhanced formation of free isophrenoids early in the sequence of kerogen alteration these results are significant to the use of isoprenoids as geochemical marker oils bitumens and kerogens and to the determination of the structure and diagenesis of isoprenoid precursors

erratum geochemistry and assemblage accretion of metavolcanic rocks in the beardmore geraldton greenstone belt superior province the beardmore geraldton greenstone belt lies between the wabigoon volcanic arc onaman tashota terrane and the quetico metasedimentary subprovince and thus has an important bearing on the accretionary model that has been proposed for the amalgamation of these terranes this paper presents geochemical evidence for the petrogenetic affinities of the volcanic units of the western half of the beardmore geraldton greenstone belt these data suggest that the metavolcanic rocks of the greenstone belt form a series of distinct packages trace element data are used to demonstrate the similarities and differences of each unit of lavas and to characterize their source region and likely tectono magmatic setting the data indicate that three separate fragments of volcanic crust representing oceanic crust arc crust and back arc crust formed in a small arc system and were juxtaposed prior to collision with the wabigoon arc these fragments of crust were then accreted to the wabigoon arc where sedimentation was follow

propagation mechanisms for the madden julian oscillation the madden julian oscillation mjo is examined using 20 years of outgoing long wave radiation and national centers for environmental prediction national center for atmospheric research re analysis data two mechanisms for the eastward propagation and regeneration of the convective anomalies are suggested the first is a local mechanism operating over the warm pool region at the phase of the mjo with a dipole structure to the convection anomalies there is enhanced tropical convection over the eastern indian ocean and reduced convection over the western pacific over the equatorial western indian ocean the equatorial rossby wave response to the west of the enhanced convection includes a region of anomalous surface divergence associated with the anomalous surface westerlies and pressure ridge this lends to suppress ascent in the boundary layer and shuts off the deep convection eventually leading to a convective anomaly of the opposite sign over the indonesian sector the equatorial kelvin wave response to the east of the enhanced convection includes a region of anomalous surface convergence into the anomalous equatorial surface easterlies and pressure trough which will tend to favour convection in this region the indonesian sector is also influenced by an equatorial rossby wave response of opposite sign to the west of die reduced convection over the western pacific which also has a region of anomalous surface convergence associated with its anomalous equatorial surface easterlies and pressure trough hence convective anomalies of either sign tend to erode themselves from the west and initiate a convective anomaly of opposite sign via their equatorial rossby wave response and expand to the east via their equatorial kelvin wave response the second mechanism is global involving an anomaly completing a circuit of the equator enhanced convection over the tropical western pacific excites a negative mean sea level pressure m s l p anomaly which radiates rapidly eastward as a dry equatorial kelvin wave at approximately 35 m s 1 over the eastern pacific it is blocked by the orographic barrier of the andes and central america for several days before propagating through the gap at panama after rapidly propagating as a dry equatorial kelvin wave over the atlantic the m s l p anomaly is delayed further by the east african highlands before it reaches the indian ocean and coincides with the development of enhanced convection at the start of the next mjo cycle

vertical diabatic heating structure of the mjo intercomparison between recent reanalyses and trmm estimates abstractcapitalizing on recently released reanalysis datasets and diabatic heating estimates based on tropical rainfall measuring mission trmm the authors have conducted a composite analysis of vertical anomalous heating structures associated with the madden julian oscillation mjo because diabatic heating lies at the heart of prevailing mjo theories the intention of this effort is to provide new insights into the fundamental physics of the mjo however some discrepancies in the composite vertical mjo heating profiles are noted among the datasets particularly between three reanalyses and three trmm estimates a westward tilting with altitude in the vertical heating structure of the mjo is clearly evident during its eastward propagation based on three reanalysis datasets which is particularly pronounced when the mjo migrates from the equatorial eastern indian ocean eeio to the western pacific wp in contrast this vertical tilt in heating structure is not readily seen in the three trmm product

organic geochemistry and organic petrology of organic rich sediments within the hauptdolomit formation triassic norian of the northern calcareous alps organic rich intercalations toc up to 50 occur within the hauptdolomit the principal components of the organic matter are lamellar alginite prebitumen or solid bitumen epi impsonite organic geochemistry shows the om to be marine and to have a high bacterial contribution a mesohaline environment low terrigenous supply high production of hc rich om high microbial activity and anoxic conditions are seen as factors favouring the formation of these rocks pyrolysis gas chromatography is used to characterize the om based on the abundance of alkene alkane doublets alkyl thiophenes alkyl benzenes and or c15 alkanes biomarker data shows that the samples cover a range from immature to overmature restricted lagoons and special basins within the hd carbonate platform are suggested as the two different paleoenvironmental settings for the deposition of these rocks

systematic decomposition of the madden julian oscillation into balanced and inertio gravity components we present a new method for the three dimensional multivariate decomposition of the mjo into balanced and inertio gravity ig components the method analyzes global fields with no filtering involved and it provides a quantitative comparison between the contribution of the rossby kelvin and other balanced and ig modes to the mjo circulation and its teleconnections results based on the era interim reanalysis data and the multivariate mjo index show that the rossby mode with the lowest meridional index is the largest contributor to the mjo circulation over the pacific a smaller role of the kelvin mode is diagnosed over the indian ocean and the maritime continent the mjo teleconnections in the polar stratosphere appear associated with the leading balanced vertical modes the presented method shows new ways of evaluating the mjo structure and its global impacts in weather and climate models

u pb ages for late magmatism and regional deformation in the shebandowan belt superior province canada five precise u pb zircon and titanite ages from different lithologic units of the shebandowan greenstone belt in the western wawa subprovince of the superior province put tight constraints on the time of late archean magmatism and of two major deformation events a porphyry sill from the older supracrustal sequence has an age of 2733 3 ma another porphyritic rock a trondhjemite occurring as a clast in a conglomerate of the unconformably overlying timiskaming type supracrustal sequence formed 2704 2 ma ago and defines a maximum age for the deposition of the timiskaming type sequence an alkalic volcanic rock from this sequence has been directly dated at in accord with the above constraint and with another probable maximum age of deposition given by the date of 2696 2 ma for the shebandowan lake pluton a first deformation event d1 was related to a predominantly vertical tectonic regime and occurred during or before intrusion of the shebandowan lake pluton at 2696 2 ma the second deformatio

folds and folding in the beardmore geraldton fold belt the beardmore geraldton fold belt forms a transitional crustal segment between the quetico and wabigoon subprovinces of the canadian shield bedding surfaces so and a bedding plane schistosity s1

a study of the holzener asphaltkalk northern germany observations regarding the distribution composition and origin of organic matter in an exhumed petroleum reservoir abstract the holzener asphalkalk deposit is located on the southwestern flank of the hils syncline northern germany it consists of a series of kimmeridgian portlandian bitumen impregnated limestones cumulative thickness of nearly 200 m overlain unconformably by neocomian claystones and underlain by older jurassic and triassic sediments the most bitumen rich limestone layers have been extensively mined with the result that there is three dimensional access to what is probably an exhumed series of stacked petroleum reservoirs geochemical petrological and petrophysical techniques were used to gain some insight into the distribution and the source of the organic matter in two of the 13 layers of the deposit most disseminated organic matter was found to be soluble in organic solvents and rich in non hydrocarbons its distribution appears to be controlled by ooid versus carbonate matrix abundances the occurrence of fractures and degree of impregnation small meso to micro pores have high bitumen saturations whereas large pores meso to macro have much lower saturations mature petroleum is thought to have once filled all pores but alteration has probably removed as much as 85 of it mainly from the large pores regional geochemical considerations pyrolysis and stable carbon isotope data indicate that the original petroleum was most probably derived from the underlying posidonia shale toarcian source rock asphaltene pyrolysis data indicate that an algal lacustrine co source might have also contributed to the deposit

synoptic analysis of the pacific north american teleconnection pattern in this study we use various diagnostic techniques to investigate the synoptic evolution of the pacific north american teleconnection pattern pna national center for environment prediction national center for atmospheric research reanalysis data are used these data cover the years 1948 2008 for the months of november march it is found that the positive pna is initiated by enhanced convection over the western tropical pacific and weakened convection over the tropical indian ocean the excitation of the negative pna exhibits opposite features for both phases the response to tropical convection excites a small amplitude pna about 8 12 days prior to the pattern attaining its maximum amplitude this is followed by slow steady growth for about 5 days after which driving by synoptic scale waves via their eddy vorticity flux together with stationary eddy advection lead to much more rapid growth and the establishment of the full pna for the positive pna the synoptic scale waves propagate eastward into the midlatitude northeastern pacific where they are observed to undergo cyclonic wave breaking for the negative pna the synoptic scale waves first amplify over the midlatitude northeastern pacific and then propagate equatorward into the subtropics where they undergo anticyclonic wave breaking once established for both phases the pna appears to be maintained through a positive feedback that involves a succession of wave breakings these results suggest that preconditioning may play an important role in the formation of the pna for the positive pna in its early development the strengthening and eastward extension of the subtropical jet result in an increase in the cyclonic shear and a decrease in the meridional potential vorticity gradient features that are known to favour cyclonic wave breaking for the negative pna opposite changes were observed for the background flow which favour equatorward wave propagation and anticyclonic wave breaking the role of optimal growth is also discussed our results also suggest that the pna is potentially predictable 1 2 weeks in advance copyright 2011 royal meteorological society

recognizing and compensating for interference from the sediment s background organic matter and biodegradation during interpretation of biomarker data from seafloor hydrocarbon seeps an example from the marco polo area seeps gulf of mexico usa abstract a suite of seep samples from the vicinity of the marco polo field in the green canyon area of the gulf of mexico provides an exceptional opportunity to study the impact of interference from sediment background organic matter and alteration by biodegradation on thermogenic hydrocarbons from seafloor seeps these seep samples contain a range in both the concentration of seeped hydrocarbons present and level of biodegradation experienced in addition the subsurface oil that sources the seepage was available for comparison the results of the study show that it is essential to have the biomarker data from the sediment s background organic matter when dealing with low concentration seepage these data provide a means to characterize the contribution of background organic matter to the biomarker distributions this in turn allows the identification of thermogenic hydrocarbons when the concentration of seeped oil in seafloor sediments is low in high concentration seepage the hopanes and regular steranes were found to be more susceptible to near surface microbial alteration while tricylic tetracyclic terpanes diasteranes monoaromatic steroids and triaromatic steroids were more resistant if biodegradation is severe enough all biomarker compounds are vulnerable to alteration and very little information is preserved in an effort to reconstruct the altered distributions low temperature pyrolysis of the seeped oils asphaltenes was done to liberate occluded biomarkers compounds although biomarkers were recovered they did not resemble the parent oil characteristics of some of the recovered biomarker distributions suggest alteration by biodegradation this implies the three dimensional structure of the asphaltenes may not offer complete protection from microbial attack these results demonstrate why interpretation of biomarker data from seafloor seeps can be a difficult task care must be taken to recognize contributions from the sediment s background organic matter as well as identify alteration by biodegradation failure to understand these processes can lead to erroneous interpretations being made about the seep s parent oil and source rock

the relationship between the madden julian oscillation and the north atlantic oscillation in this study the relationship between the madden julian oscillation mjo and the north atlantic oscillation nao is investigated by analyzing nao events both when the mjo is active and inactive the european centre for medium range weather forecasts re analysis era interim dataset is used for the years 1979 2006 and the months of december february when the mjo is active negative positive nao events are preceded by enhanced mjo convection over the tropical western and central pacific ocean tropical indian ocean and maritime continent the accompanying sea level pressure slp anomaly fields reveal patterns that closely resemble the northern annular mode nam the mjo related negative nao events are preceded by an increase in the vertical propagation of planetary scale wave activity into the stratosphere followed by a marked weakening of the zonally symmetric component of the lower stratospheric zonal wind the opposite behaviour is found for the mjo related positive nao events the mjo related nao events are also long lived persisting for approximately 30 days in contrast when the mjo is inactive there is little change to the zonally symmetric component of the lower stratospheric zonal wind these events are relatively short lived lasting for about 10 days and the nao corresponds to dipole that is confined to the north atlantic

the impact of the initial flow on the extratropical response to madden julian oscillation convective heating abstractthe response to the madden julian oscillation mjo over the pacific north american pna region is investigated in addition the sensitivity of this response to the interaction between madden julian oscillation forcing and the extratropical initial flow is explored first a simple dynamical model is run with an ensemble of 100 randomly selected initial conditions from era interim data with no heating mjo phase 1 like heating and mjo phase 5 like heating the 300 hpa geopotential height field is separated into a part that would evolve without an active mjo present and a part that is a consequence of the mjo heating a negative 300 hpa geopotential height anomaly centered over northeastern china bounded by positive anomalies on its equatorward and poleward flanks is found to be followed by a large amplitude negative pna like response for mjo phase 1 and a positive pna like response for phase 5 a similar study is carried out using observational data an analog approach using projections to det

subprovince accretion tectonics in the south central superior province development of tectonic subprovinces as shear bounded granite greenstone and sediment dominated terranes during the late archaean is reviewed and interpreted from relationships between portions of

the development of upper tropospheric wind over the western hemisphere in association with mjo convective initiation abstractthis study examines the structure and driving mechanisms of upper tropospheric intraseasonal zonal wind anomalies over the western hemisphere wh during the convective initiation of the madden julian oscillation mjo over the indian ocean using composite and budget analyses the initiating mjo convection is more often associated with wh upper tropospheric intraseasonal easterly wind anomalies and when it is it tends to develop a stronger and zonally broader envelope of enhanced convection than events associated with westerly wind anomalies the wh upper tropospheric zonal wind anomaly associated with the mjo is often described as a dry kelvin wave radiated from mjo convection but the results show that both the structure and driving mechanisms are different from the ones of theoretical kelvin waves unlike the theoretical kelvin wave the zonal wind anomaly is not driven mainly by the zonal pressure gradient force and it is strongly coupled with rotational wind associated with subtropical and

contrasts in the response to dextral transpression across the quetico wawa subprovince boundary in northeastern minnesota folds and shear zones in the central and western vermilion district greenstone belt wawa subprovince are consistent with deformation in a regime of regional dextral transpression however the shear strain associated with this deformation regime is only locally evident in the schist and migmatite of the adjacent southeastern vermilion granitic complex vgc quetico subprovince we suggest that differential partitioning of shear and flattening strains between the two terranes was controlled by the lower ductility higher competency contrast and steeper dip of orogen parallel rock units in the vermilion district compared with the variably oriented rocks in the adjacent vgc contact strains adjacent to plutonic bodies played a greater role in the development of complex fold geometries in the vgc in the central vermilion district northwest directed subhorizontal shortening produced easterly striking zones of brittle ductile dextral shear and northeast trending en echelon folds the en echelon folds with

boreal winter links between the madden julian oscillation and the arctic oscillation abstract there is increasing evidence that the madden julian oscillation mjo modifies the mid to high latitude circulation and in particular appears to have a relationship to the leading mode of extratropical variability the arctic oscillation ao in this study new insights into the observed similarities between the mjo and the ao are explored it is shown that the eastward progression of the convectively active phase of the mjo is associated with a corresponding shift in the tendency and sign of the ao index moreover the ao and the mjo share several analogous features not only in the global circulation but also in surface temperature fields also the ao is linked to a pattern of eastward propagating mjo like variability in the tropics that is partially reproduced in free runs of the ncep climate forecast system cfs model finally it is shown that the structure of the ao as defined by the leading mode in the 1000 hpa geopotential height field is significantly altered based on the phase o

pyrolysis gas chromatography of asphaltenes and kerogens from source rocks and coals a comparative structural study abstract pyrolysis gas chromatography of asphaltenes isolated from source rock and coal extracts and the corresponding kerogens show the same general pyrolysis characteristics while the pyrograms of asphaltenes associated with type i and ii kerogens are dominated by an aliphatic n alkene n alkane homology the pyrolysates of coal asphaltenes show a high abundance of aromatics the asphaltene pyrolysates differ from those of the related kerogens principally in that the relative abundance of isoprenoids and long chain hydrocarbons is higher in the asphaltene pyrograms these differences were minimized with increasing maturity suggesting comparable structures for mature asphaltenes and kerogens and that pyrolysis of asphaltenes should be integrated with other methods which are used in source rock geochemistry

analysis of petroleum fractions by tlc fid applications to petroleum reservoir description abstract thin layer chromatography and flame ionization detection iatroscan tlc fid offers a rapid and accurate method for quantifying saturated and aromatic hydrocarbons and resin asphaltene fractions in solvent extracts of petroleum source rocks reservoir rocks and crude oils while the instrument is superficially simple special precautions need to be taken in calibration and parameter setting due to complexities arising from the operational characteristics of the detector system nevertheless the technique offers superior speed and precision to conventional mplc analysis of petroleum fractions this paper describes the choice of operational parameters provides comparison with the traditional group type analysis technique mplc and presents some geochemical applications

why do similar patterns of tropical convection yield extratropical circulation anomalies of opposite sign abstracttropical precipitation anomalies associated with el nino and madden julian oscillation mjo phase 1 la nina and mjo phase 5 are characterized by a tripole with positive negative centers over the indian ocean and central pacific and a negative positive center over the warm pool region however their midlatitude circulation responses over the north pacific and north america tend to be of opposite sign to investigate these differences in the extratropical response to tropical convection the dynamical core of a climate model is used with boreal winter climatology as the initial flow the model is run using the full heating field for the above four cases and with heating restricted to each of seven small domains located near or over the equator to investigate which convective anomalies may be responsible for the different extratropical responses an analogous observational study is also performed for both studies it is found that despite having a similar tropical convective anomaly spa

geochemistry of asphaltenes abstract asphaltenes derived from both oil and source rocks have been studied by pyrolysis gas chromatography the pyrograms obtained at 450 and 550 c show that asphaltene structure is very close to the structure of the kerogen of the same sample they can be interpreted as kerogen moieties resulting from its early evolution therefore they can be used as substitutes of kerogen in genetic studies consequently asphaltenes pyrolysis appear to be a tool in correlation studies for oil oil correlation it can supplement and even replace in the case of degraded oils the information given by hydrocarbon distributions for oil source rock correlations the match between pyrograms of asphaltenes from both oil and source rocks offers more direct possibilities than usual techniques

thermo tectonic evolution of an archean accretionary complex u pb geochronological constraints on granulites from the quetico subprovince ontario canada abstract u pb geochronological data have been obtained for a granulite zone in the quetico subprovince an archean accretionary complex of the superior province north of manitouwadge ontario canada this granulite zone represents the culmination of a low pressure high temperature regional metamorphism in the quetico subprovince and an apparent continuation of a northward increase in metamorphic grade in the wawa subprovince and across the quetico wawa boundary a u pb zircon age of 2666 1 ma from a concordant magnetite bearing granitic pegmatite in the quetico granulite zone is consistent with the inferred timing of regional metamorphism in amphibolite facies zones 2671 2665 ma and indicates that the low pressure high temperature metamorphism in the quetico subprovince commenced during the main compressional deformation titanite in a calc silicate rock from low leucosome fraction layered migmatites that might represent incipient melting gave a 207pb 206pb age of 2658 1 ma the timing of the granulite facies metamorphism is constrained by u pb zircon ages of 2650 2 and 2651 3 ma from mafic granulite and garnet bearing tonalitic leucosome respectively that are similar to reported u pb ages for mafic granulites in the upper levels of the kapuskasing structural zone the present u pb data suggest a diachronous development of peak metamorphic conditions of the regional metamorphism in the quetico and wawa subprovinces this diachronous development and the zonal distribution of the regional metamorphism are probably related to oblique collision at a convergent plate margin and differential rates of erosional uplift away from the quetico wawa boundary

trench and slope basin deposits in an archean metasedimentary belt superior province canadian shield the identification of a late archean arc trench assemblage in northwestern ontario provides the opportunity to compare depositional systems developed in a precambrian convergent setting with cenozoic examples two types of sedimentary associations exist in the accretionary complex medium to thick bedded bouma a ab and abc felsic turbidites dominate the belt these are primarily organized into unstructured sequences and reflect deposition in a ramp like environment with multiple feed points supplying sediment from a forearc basin mafic turbidites with possible shallow water reworked intervals form isolated pods within the metasedimentary belt erosion of upthrust blocks of sedimentary strata containing ultramafic masses supplied this sediment to elevated slope basins these types of depositional systems are similar in many respects to those developed in cenozoic and holocene arc trench settings

geological evolution of the manitouwadge greenstone belt and wawa quetico subprovince boundary superior province ontario constrained by u pb zircon dates of supracrustal and plutonic rocks fifty million years of archean evolution is recorded in the manitouwadge greenstone belt and the wawa quetico boundary region from ca 2720 ma volcanism and subvolcanic plutonism associated with m

the structural history of a part of the archaean quetico metasedimentary belt superior province canada abstract the first generation structures of the quetico metasedimentary belt are large scale recumbent folds which in the kashabowie area are northwestward vergent and facing that is they face towards the centre of the metasedimentary belt during this folding basaltic pillows were elongated normal to fold hinges and a schistosity was developed subsequent deformation has largely destroyed the schistosity but the pillow elongation remains although reoriented second generation tight to isoclinal upright folds are characteristic of the belt and have an associated prominent but not perfectly axial planar schistosity s 2 refolding of earlier folds causes second generation folds to be either upward or downward facing depending upon whether the present exposure level is either above or below the earlier fold axial surface third generation close to tight asymmetric folds which become markedly disharmonic or convoluted at the highest metamorphic grades crenulate and fold the subvertical s 2 schistosity towards the centre of the belt folding and generation of s planes pre dates the metamorphic peak in the central part of the belt and post dates metamorphism at the belt margin but deformation continued as the belt cooled post folding brittle and brittle ductile structures such as extension gashes shear fractures tension gashes and boudinage of post folding quartz veins all indicate layer parallel extension throughout the belt anisotropy within the metagrey wackes and metapelites controls the location of many of these minor structures the orientation and geometry of the structures indicate that an early period of gravitational instability in the adjacent shebandowan volcanic belt granite greenstone terrain produced recumbent folds directed towards the metasedimentary belt subsequently the quetico metasedimentary belt experienced subhorizontal shortening normal to and subhorizontal extension parallel to its axis for most of its history including both the heating and cooling stages

a study of natural and artificially generated light hydrocarbons c4 c13 in source rocks and petroleum fluids from offshore mid norway and the southernmost norwegian and danish sectors abstract the free or natural light hydrocarbon composition obtained by thermal extraction gc of source rock samples is compared with the light fraction generated by pyrolysis products of the kerogens even though there are large differences between the composition of the free c 4 c 13 hydrocarbon fraction and the same fraction generated by pyrolysis some characteristics have been detected which can be used interchangeably for both data types visual inspection of gas chromatograms from thermal extracts and pyrolysates indicates that in particular the relative content of m p xylene corresponds well between these two analytical methods the source rock samples used are upper jurassic marine shales and middle and lower jurassic coals and coaly shales from offshore mid norway and denmark more detailed analysis of the data shows that the most effective parameter which can distinguish between different source rock types in both thermal extracts and pyrolysates is the m p xylene n c 8 ratio this parameter has been used to derive classification diagrams for interpreting the source of light hydrocarbons of both natural petroleum fluids analysed by gas chromatography and the same fraction generated by pyrolysis of asphaltenes from the fluids the model was first tested on 17 natural petroleum fluids from mid norway since a comprehensive study of light hydrocarbon distributions already has been published further the parameter was applied to correlate with asphaltene pyrolysates of the fluids from mid norway and a total of 22 natural oils and condensates from the southernmost norwegian and danish sectors

convection over the pacific warm pool in relation to the atmospheric kelvin rossby wave abstract deep convection over the western tropical pacific warm pool is analyzed in terms of its relation to the atmospheric kelvin rossby wave which dominates the large scale flow during the austral summer the study uses doppler radar data collected by aircraft and ship radars during different time periods in the tropical ocean global atmosphere coupled ocean atmosphere response experiment to characterize the mesoscale circulations of organized convective cloud systems occurring throughout the season the study focuses on convection in two contrasting phases of the wave the westerly onset region just west of the point within the wave where low level easterlies change to westerlies and the strong westerly region or westerly wind burst lying between the large scale counterrotating gyres of the kelvin rossby wave in the westerly onset region the zonal wind component had midlevel easterlies overlying low level westerlies in the strong westerly region a deep layer of westerlies extended from the

the interaction of the madden julian oscillation and the arctic oscillation abstract tropical and extratropical interactions on the intraseasonal time scale are studied in the context of the arctic oscillation ao and the madden julian oscillation mjo to simplify the discussion a high low mjo phase is defined as strong suppressed convective activity over the indian ocean in the northern hemisphere nh winter season a high low ao phase is found more likely coupled with a high low mjo phase based on the regressed patterns and composites of various dynamical fields and quantities possible mechanisms linking the ao and the mjo are examined the analysis indicates that the mjo influence on extratropical circulations seems more evident than the ao influence on tropical circulations the mjo interacts with the ao through meridional dispersion of rossby waves in the pacific sector the geopotential height anomaly center over the north pacific associated with the mjo can either reinforce or offset the ao pacific action center as a result the ao pattern can be greatly a

shebandowan greenstone belt western superior province u pb ages tectonic implications and correlations the shebandowan greenstone belt of the western wawa subprovince consists of successions of volcanic and sedimentary rocks impinging onto the metasedimentary quetico subprovince to the north and cored by a batholithic complex to the south u pb geochronology using mainly zircon and titanite demonstrates a relatively rapid accretion of the greenstone belt in the late archean the oldest ages were obtained for 2750 ma tonalitic gneiss and sporadic 2830 2750 ma detrital or xenocrystic zircons a major phase of greenstone belt construction at 2720 ma formed ultramafic to felsic volcanic rocks and peridotitic gabbroic and anorthositic bodies probably in an extensional arc backarc setting these units are laterally correlative with volcanogenic massive sulfide bearing assemblages in the central wawa subprovince and probably with similar successions in northern minnesota the second major stage of felsic volcanism and plutonism at about 2695 ma was associated with d 1 compression causing thrusting imbrication and sedimentation this was succeeded by the deposition of an unconformable sequence of calc alkalic to alkalic volcanic and sedimentary rocks and emplacement of tonalitic to syenitic plutons at about 2690 ma transpressive deformation d 2 constrained between 2685 and 2680 ma caused the development of locally penetrative structures and deposition of clastic sedimentary packages the emplacement of plutons at 2683 2680 ma concluded the evolution of the greenstone belt titanite and rutile yield ages in the same range as zircon showing that the greenstone belt was situated at high crustal levels by 2680 ma and escaped the younger and intense deformational metamorphic events recorded in greenstone belts farther east in the central wawa subprovince as well as in the immediately adjacent migmatitic quetico subprovince to the north

new insights on the green river petroleum system in the uinta basin from hydrous pyrolysis experiments discussion in their recent paper ruble et al 2001 use hydrous pyrolysis experiments to correlate oils to source rocks and to derive kinetic parameters for potential source facies in the green river formation uinta basin they then use these correlations and kinetic parameters in a basin model to explain the occurrence of overpressured producing intervals this discussion focuses on their results for the calculation of hydrocarbon generation kinetics from hydrous pyrolysis data the temperatures of generation predicted by the hydrous pyrolysis derived kinetics in ruble et al 2001 are not consistent with data at either geological or laboratory timescales this lack of consistency indicates that these kinetics although valid over a narrow range of laboratory conditions cannot be applied to a wider range of thermal conditions furthermore the temperatures of generation predicted by these kinetics are not consistent with the proposed basin model the major sources of these inconsistencies appear to be 1 the use of the appearance of immiscible oil during hydrous pyrolysis i e the free floating liquid phase to calculate kinetic parameters 2 the omission of the effects of product cracking in closed system pyrolysis on calculated yields and kinetics extrapolation of the hydrous pyrolysis derived kinetics in ruble et al 2001 to geological conditions at a heating rate of 1 c m y predicts that significant generation transformation ratio 0 10 does not occur until approximately 170 c and peak generation is not reached until almost 185 c figure 1 however these temperatures far exceed the temperatures at which oil generation is generally accepted as occurring in nature even in lacustrine environments e g tissot and welte 1984 hunt 1996 figure 1 evolution of transformation ratio and generation rate predicted by ruble et al 2001 kinetics at a 1 c m y heating rate in addition these predicted generation temperatures are higher than the temperatures at which significant oil cracking occurs for

autochthonous development of superior province greenstone belts abstract models for superior province greenstone belt development have changed over the last 30 years from ensimatic generally autochthonous models to suspect allochthonous terrane models based on the plate tectonic paradigm models intermediate between these end members such as autochthonous terrane models have not been prominent within the superior province there is a secular variation from early ca 3 ga platformal assemblages with overlying rift related komatiite tholeiite units representing breakup of ca 3 ga continental fragments to late ca 2 7 ga pull apart basins autochthonous terranes should demonstrate some sort of logical order such as that described above whereas allochthonous terranes will be largely oceanic in character and should be essentially random in their occurrence rather than exhibiting secular order in the face of this situation this paper reviews evidence from throughout the superior province that suggests many but not all greenstone assemblages developed autochthonously or parautochthonously the earliest greenstone assemblages in the superior province are generally quartzite and carbonate bearing platform sequences in the north caribou terrane and the marmion terrane deposited unconformably upon granitoid or greenstone basement the evidence for autochthonous parautochthonous development includes the presence of unconformities between keewatin type greenstone units such as 1 basal unconformities between ca 3 ga granitoid or volcanic basement and slightly younger platformal assemblages 2 between ca 2 9 ga platformal assemblages and younger platformal and andean arc assemblages stratigraphic patterns such as adjacent greenstone belt assemblages representing sharply differing geodynamic settings with some indication of palinspastic order or progression in the northern central and southern superior province are considered suggestive of orderly autochthonous progression from platforms through rifting of continental fragments and late assembly during the kenoran orogeny petrogenetic data indicating involvement of older granitoid crust in genesis of greenstone assemblages of a variety of ages throughout the superior province suggests the presence of older basement implying autochthonous or parautochthonous development of many assemblages younger greenstone assemblages in the abitibi wawa subprovince and the north caribou terrane contain xenocrystic zircons similar in age to stratigraphically underlying greenstone assemblages this pattern has been interpreted to represent autochthonous greenstone development the current above enumerated evidence for autochthonous development of greenstone assemblages is generally indirect few actual unconformities between keewatin type greenstone assemblages have been recognized in the superior province to aid in future recognition of unconformities in keewatin type greenstone assemblages examples of unconformities of varying degrees of subtlety in archean sequences are reviewed archean unconformities ranging from sharp angular discordances in the northern superior province to subtle stratigraphic patterns to weathering related geochemical mobilization along inter formational contacts are described these styles of unconformity in archean sequences suggest previously unrecognized major disconformities and unconformities may well exist between keewatin type assemblages in the superior province generally and the abitibi wawa subprovince specifically the most important disconformity suggested in the abitibi wawa subprovince is between the ca 2726 ma deloro and the ca 2708 ma tisdale assemblages the presence of unconformities and disconformities coupled with the indirect lines of evidence cited above suggest an autochthonous origin for many superior province greenstone belts this autochthonous origin involves either autochthonous or parautochthonous evolution of assemblages at least in part in place that is development of ca 3 ga platform sequences in selected locales followed by in place evolution of a succession of plume oceanic and arc assemblages culminating in late pull apart basin sequences implications of the autochthonous model for greenstone belts of the superior province particularly the abitibi wawa subprovince include the future ability to recognize unconformity bounded sequences potentially improving regional scale correlation

possible chemical structures and biological precursors of different vitrinites in coal measure in northwest china abstract chemical structure of jurassic vitrinites isolated from the coals in basins in nw china have been checked using solid state 13c nmr and flash pyrolysis gc ms study shows some jurassic collodetrinites are rich in aliphatic products in pyrolysates consisting with the high amount of methylene carbon in 13c nmr spectra in contrast pyrolysates of jurassic collotelinites are rich in phenols and alkylbenzenes also one pennsylvanian and one permian vitrinite selected from the ordos basin nw china have been checked for comparison the proportion of aliphatics is low in pyrolysates and aliphatic carbon peak in 13c nmr spectrum of permian vitrinite is mostly composed of gas prone carbons compared with collodetrinites in those jurassic basins but both pyrolysis and 13c nmr data shows the pennsylvanian vitrinite is not only gas prone but also oil prone relatively high proportion of long chain aliphatic structure of some jurassic vitrinite in junggar turpan hami basins may be due to the contribution of liptodetrinites which may be included during the formation of vitrinites and it seems that suberinite is the most possible precursor of long chain aliphatics in the structure of jurassic collodetrinite

strain in an archean greenstone belt of minnesota abstract we measured strain at more than 60 locations in metasedimentary and metavolcanic rocks of the vermilion district an e w trending archean greenstone belt in minnesota strain ellipsoid orientations and shapes correlate strongly with n s location in the belt but magnitudes do not flattening strains occur near the present vermilion fault which bounds the greenstone belt to the north with constrictional strains to the south the observed strain patterns can be mathematically modeled by deformation paths which produce the flattening strains with west plunging 1 axes by dextral shear of the constrictional strains with east plunging 1 axes using reasonable geologic constraints the shear plane must dip to the north with a subhorizontal shear direction structures throughout the district also indicate dextral shear a geometrical finite element program uses the measured strains to destrain the rocks and find the configuration which most closely satisfies strain compatibility equations the linear e w strain patterns and minor rotations about horizontal axes during the deformation preclude origin of the greenstone belt by infolding and shear off the flanks of a rising granitic diapir by accounting for rotations which result in the deformed curvature of the original surface a true estimate of 50 n s shortening across the belt can be made the data and deformation models favor the origin of the vermilion district rocks at a convergent margin most likely as a n dipping subduction zone complex with shallow slab dip the origin of the constrictional strains remains enigmatic

convectively coupled equatorial waves 1 convectively coupled equatorial waves ccews control a substantial fraction of tropical rainfall variability their horizontal structures and dispersion characteristics correspond to matsuno s 1966 solutions of the shallow water equations on an equatorial beta plane namely kelvin equatorial rossby mixed rossby gravity and inertio gravity waves because of moist processes the tilted vertical structures of ccews are complex and their scales do not correspond to that expected from the linear theory of dry waves the dynamical structures and cloud morphology of ccews display a large degree of self similarity over a surprisingly wide range of scales with shallow convection at their leading edge followed by deep convection and then stratiform precipitation mirroring that of individual mesoscale convective complexes ccews have broad impacts within the tropics and their simulation in general circulation models is still problematic although progress has been made using simpler models a complete understanding of ccews remains a challenge in tropical meteorology

the global response to tropical heating in the madden julian oscillation during the northern winter a life cycle of the madden julian oscillation mjo was constructed based on 21 years of outgoing long wave radiation data regression maps of ncep ncar reanalysis data for the northern winter show statistically significant upper tropospheric equatorial wave patterns linked to the tropical convection anomalies and extratropical wave patterns over the north pacific north america the atlantic the southern ocean and south america to assess the cause of the circulation anomalies a global primitive equation model was initialized with the observed three dimensional 3d winter climatological mean flow and forced with a time dependent heat source derived from the observed mjo anomalies a model mjo cycle was constructed from the global response to the heating and both the tropical and extratropical circulation anomalies generally matched the observations well the equatorial wave patterns are established in a few days while it takes approximately two weeks for the extratropical patterns to appear the model response is robust and insensitive to realistic changes in damping and basic state the model tropical anomalies are consistent with a forced equatorial rossby kelvin wave response to the tropical mjo heating although it is shifted westward by approximately 20 longitude relative to observations this may be due to a lack of damping processes cumulus friction in the regions of convective heating once this shift is accounted for the extratropical response is consistent with theories of rossby wave forcing and dispersion on the climatological flow and the pattern correlation between the observed and modelled extratropical flow is up to 0 85 the observed tropical and extratropical wave patterns account for a significant fraction of the intraseasonal circulation variance and this reproducibility as a response to tropical mjo convection has implications for global medium range weather prediction copyright 2004 royal meteorological society

a new look at the midlatitude mjo teleconnection in the northern hemisphere winter the midlatitude to madden julian mjo teleconnection in the northern hemisphere wintertime was investigated using twenty years of outgoing long wave radiation and national center for atmospheric research national centers for environmental prediction re analysis data it is revealed through empirical orthogonal functions and regression analyses that the tropical upper level divergence convergence associated with enhanced reduced tropical convection has a subtropical counterpart of upper level convergence divergence as the convective region of mjo moves eastward from the indian ocean to the western pacific the divergent circulation connecting the tropics and subtropics moves eastward from an analysis of vertical motion diagnosed by the generalized omega equation it was revealed that the position of the subtropical rossby gyres of the mjo with respect to the asian pacific jet was the most important factor affecting the existence of the localized divergence convergence and associated lower level vertical motion in the subtropics as the subtropical rossby gyres pass by the longitudinal position of the asian pacific jet vertical motion occurs to meet the balance required by quasi geostrophic theory since this anomalous vertical motion is large enough to cause convection at that region the diabatic heating process reinforces the vertical motion furthermore other dynamical processes neglected in quasi geostrophic theory are activated and contribute to the vertical motion balancing the diabatic heating as a result of the vertical motion near the jet entrance region in the subtropics the vorticity advection by vertical wind and the tilting of vorticity become important since these two terms are similar in shape and magnitude they reinforce each other during the development phase of the midlatitude mjo teleconnection combining these two terms we define the baroclinic jet source bjs in order to evaluate the bjs as a source for the midlatitude mjo teleconnection a numerical experiment is carried out the linear barotropic model is forced by only two terms yet the model captured clearly the main feature of the midlatitude mjo teleconnection copyright 2006 royal meteorological society

the age and provenance of metasedimentary rocks in the quetico subprovince ontario from single zircon analyses implications for archean sedimentation and tectonics in the superior province abstract u pb isotopic analyses have been performed on single detrital zircon grains from greywacke samples collected along the northern boundary of the quetico subprovince in northwest ontario secondary lead loss was virtually eliminated by choosing crack free grains and removing the outer surface using air abrasion thus the 207 pb 206 pb age can be considered a good approximation to the age of crystallization of each grain zircons in the quetico metasediments show a range of ages from 2698 3 ma to 3009 4 ma deposition and metamorphism of the metasediments is bracketed within a 10 5 ma time span between crystallization of the youngest detrital zircon grain and a late tectonic intrusion the blalock pluton which cuts the sediments and has a zircon age of 2688 4 ma the most easterly metasediment sample contains zircons with ages which cluster around 3007 6 ma which is within error of the age of a batholith dated in the adjacent marmion lake area of the wabigoon subprovince this along with the fact that most detrital zircons were only slightly abraded by sedimentary transport suggests that the source of many zircons may have been proximal from the north there is also a significant cluster of young zircon ages in the range 2698 2709 ma surprisingly only a few ages correspond to the time of most intense arc type felsic volcanism 2710 2745 ma in the main greenstone belt of the western wabigoon subprovince sedimentary deposition occurred at a time of extensive deformation in the adjacent wabigoon subprovince the pattern of detrital grain ages indicates that this involved uplift of a complex older sialic landmass petrographic evidence for the presence of substantial felsic volcanic detritus as well as the fact that many of the zircons only slightly pre date deposition indicates that much of the sediment was probably derived from erosion of active felsic volcanic centers these data combined with regional geochronological and field studies favour deposition in a basin formed by late orogenic collisional events

three dimensional structure and evolution of the mjo and its relation to the mean flow abstractthe two leading principal components of the daily 850 minus 150 hpa global velocity potential in the interim european centre for medium range weather forecasts ecmwf re analysis era interim 1979 2011 data are used as time varying madden julian oscillation mjo indices regression maps and meridional cross sections based on these indices are used to document the structure and evolution of the zonal wind u and geopotential height z anomalies in the mjo cycle the data are daily and they are not separated by season at upper tropospheric levels the mjo signature is dominated by eastward propagating planetary wave packets consisting of equatorial kelvin waves flanked by rossby waves centered along 28 n s for which the westerly jet streams serve as waveguides at lower tropospheric levels the pattern more closely resembles the response to a pulsating heat source over the maritime continent where the andes block the eastward propagating kelvin wave pulse the contrasting upper and lower

identifying the skeleton of the madden julian oscillation in observational data the madden julian oscillation mjo skeleton model offers a theoretical prediction of the mjo s structure here a method is described for identifying this structure in observational data the method utilizes projections onto equatorial wave structures and a main question is can this method isolate the mjo without using temporal filtering or empirical orthogonal functions for the data projection a wide range of data is incorporated multiple variables wind geopotential height water vapor and as a proxy for convective activity outgoing longwave radiation multiple pressure levels 850 and 200hpa and multiple latitudes both equatorial and off equatorial such a data variety is combined using a systematic method and it allows for a distinction between the kelvin and rossby components of the mjo s structure results are illustrated for some well known cases and statistical measures are presented to quantify the variability of the mjo skeleton signal mjos x t and its amplitude mjosa t the robustness of the methods is demonstrated through a suite of sensitivity studies including tests with two projection methods when the projection is based on the skeleton model s energy as opposed to the standard l 2 energy water vapor is seen to be of primary importance finally a simple interpretation is given for the mjo skeleton structure it is related to the wave responseto amovingheatsource from eitherperspective themethods hereidentifysignalsthatproject onto coupled convection circulation patterns and the results suggest that a large portion of the mjo s structure is consistent with such a coupled pattern

the generation of global rotational flow by steady idealized tropical divergence abstract tropical convective heating is balanced on the large scale by the adiabatic cooling of ascent the horizontal divergence of the wind above this heating may be viewed as driving the upper tropospheric rotational wind field a vorticity equation model is used to diagnose this relationship it is shown that because of the advection of vorticity by the divergent component of the flow the rossby wave source can be very different from the simple fd source often used in particular an equatorial region of divergence situated in easterly winds can lead to a rossby wave source in the subtropical westerlies where it is extremely effective this part of the source can be relatively insensitive to the longitudinal position of the equatorial divergence a divergence field which is asymmetric about the equator can lead to a quite symmetric rossby wave source for a steady frictionless flow the rossby wave source averaged over regions within closed streamfunction or absolute vorticity contours is under cert

a structural reappraisal of the beardmore geraldton belt at the southern boundary of the wabigoon subprovince ontario and implications for gold mineralization the beardmore geraldton belt occurs along the southern margin of the archean wabigoon subprovince superior province ontario the belt consists of shear bounded interleaved metasedimentary and metavolcanic units the units were imbricated from 2696 to 2691 ma during d1 thrusting and accretion of the wabigoon quetico and wawa subprovinces post accretion d2 deformation produced regional f2 folds that transposed lithological units parallel to the axial plane s2 cleavage of the folds during d3 deformation the folds were overprinted by a regional s3 cleavage oriented anticlockwise of f2 axial planes and lithological contacts and s2 cleavage were reactivated as planes of shear within dextral regional shear zones that generally conform to the trend of the belt d3 is a regional dextral transpression event that also affected the quetico and wawa subprovinces south of the beardmore geraldton belt gold mineralization at the leitch and macleod cockshutt mines the two richest past producing gold mines in the beardmore geraldton belt is associated with d3 shear zones and folds overprinting regional f2 folds the plunge of the ore zones is parallel to f3 fold axes and to the intersection of d3 shear zones with f2 and f3 folds

pyrolysis gas chromatography of asphaltenes kerogens from source rocks of the gandhar field cambay basin india abstract pyrolysis gas chromatography of rocks from three exploratory wells in the gandhar area of the cambay basin india reveals that the organic matter is dominated by input from higher land plants the pyrograms of asphaltenes and kerogens demonstrate that the hazad and cambay shale were deposited in different environments with the former being an overall regressive deltaic environment and the latter a marine transgressive sequence studies of toc values range from 1 to 2 6 rock eval hi values range from 70 to 183 pyrolysis gas chromatography vitrinite reflectance r o range from 0 4 to 0 8 bitumen extracts and isotopic ratios demonstrate that both hazad and upper cambay shale can act as effective source rocks wherever they are thermally mature

recent advances in petroleum geochemistry applied to hydrocarbon exploration this paper presents a critical review of recent advances in the study of generation maturation and migration of petroleum the different source potentials for generating hydrocarbons depend on the type of kerogen in addition to the classic types i ii and iii a residual oxidized organic matter is also observed which has no potential for hydrocarbon generation coal is widely considered as a potential source for gas but some coals may generate sizeable amounts of oil as well the development of routine analytical tools particularly pyrolysis makes possible the preparation of geochemical logs that are the basis for screening samples and for interpreting other analyses among optical techniques the major subjects of discussion concern the nature of amorphous organ c matter which may encompass different chemical types of kerogen and the applicability of vitrinite reflectance techniques to type i and ii kerogens following important advances in identification of biological markers in sediments and crude oils these markers are used for oil source rock correlation and proposed for reconstruction of depositional environment and subsequent thermal evolution migration of hydrocarbons is now better understood and the importance of a hydrocarbon phase migration is widely recognized overpressuring of pore fluids is mainly responsible for expulsion of petroleum geologic models of basin evolution subsidence compaction thermal history and geochemical models hydrocarbon generation and migration become progressively available their integration int a comprehensive model should be one of the major developments in future petroleum exploration

compound specific carbon isotope analysis of natural and artificially generated hydrocarbons in source rocks and petroleum fluids from offshore mid norway stable carbon isotope signatures of individual hydrocarbon components provide important information on the source rock facies of oils as well as their asphaltene fractions despite maturity variations and secondary processes such as phase fractionation and biodegradation our study is based upon petroleum fluids and source rock samples from offshore mid norway where the main source rock is the marine shales of the upper jurassic spekk formation an alternative source is provided by coals and coaly shales of the lower jurassic are formation in terms of maturity the source rock samples are distributed throughout the main phase of oil generation in this study compound specific carbon isotope analysis has been performed on thermal extracts and kerogen pyrolysates of the source rocks as well as on the oils and the pyrolysis products of their asphaltenes we demonstrate that trends of absolute isotope data and specific isotopic fingerprints after normalizing the data are useful for petroleum source rock correlations the carbon isotope ratios of the n alkanes separate the are from the spekk formation samples in both thermal extracts and kerogen pyrolysates becoming less negative with increasing terrestrial input the spekk samples also tend to become isotopically heavier with increasing maturity while the are samples do not show any systematic difference with increasing maturity the carbon isotope ratios of the n alkanes also discriminate between the oils as well as the asphaltenes from the fluids the individual components generated by pyrolysis of kerogens are isotopically heavier than those from the thermal extracts this is expected from models of kinetic isotope effects which predict that the isotopically lightest products are generally released at an earlier stage in the maturation process a similar isotopic difference is also observed between the pyrolysis products of asphaltenes and the original oils derived from the same source rock type however in a sample where the oil and its asphaltene fraction originate from two different source rocks the opposite relationship between the carbon isotope composition of the oil and its asphaltene fraction is observed bulk isotope data of kerogen concentrates pyrolysates and the residue after pyrolysis of the source rock samples as well as bulk isotope data of whole oils are also presented we show that besides separating are from spekk the bulk carbon isotope values of the spekk samples are considerably heavier than the n alkanes from the thermal extracts whereas those of the are samples are almost equal

microfacies and petroleum properties of coals as revealed by a study of north sea jurassic coals abstract the influence of the composition and microstructural aspects of coal microfacies on petroleum properties were investigated in light of petrographic and geochemical studies the first study concerns a collection of north sea jurassic coals of various maceral compositions the second study is a pyrolysis gas chromatography study on pure microlithotypes from a similar french jurassic coal the results show that hydrocarbon potential is logically increased by a high content in liptinite but more often in hydrogen rich vitrinite in the same way the hydrocarbon potential is reduced by a high inertinite content mainly due to pre sedimentary oxidation of the original biomass but also due to early diagenetic processes that lead especially to the formation of micrinite or to post sedimentary alterations these trends indicate that total hydrocarbon potential is increased by an autochthonous origin of the organic matter that was deposited in a relatively closed paleoenvironment and thus protected from detrital and organo detrital inputs finally the oil potential of humic coals as determined by open pyrolysis gas chromatographic studies as related to the weight of rock is similar to classical source rocks the structural aspects of the coal microfacies which probably play a role in the release of oil from coal seams in natural conditions are also discussed

sedimentology organic geochemistry and petroleum potential of jurassic coal measures tarim junggar and turpan basins northwest china lower and middle jurassic coal bearing strata occur widely throughout central asia and are well developed in northwestern china where their thicknesses in the southern junggar northern tarim and turpan basins exceed 2500 2300 and 1500 m respectively examination of these strata along 13 transects across basin margin outcrop belts indicates that they are entirely nonmarine meandering fluvial deposits with local development of braided fluvial and lacustrine deltaic facies chinese subsurface data suggest that regional jurassic lacustrine facies are present down depositional dip consistent with predictions from global circulation modeling of early and middle jurassic monsoonal precipitation laboratory analyses of coals and organic rich shales show a dominance of terrestrial higher plant components visual kerogen analysis indicates that vitrinite inertinite and exinite are the dominant macerals and elemental analysis characterizes most kerogens as type iii rock eval analyses yield moderate hydrogen index values 50 300 and very low oxygen index values 20 jurassic source rock extracts are characterized by odd over even normal alkane distributions high pristane phytane and high hopane sterane ratios dominance of c29 sterane homologs local abundance of diterpenoid compounds and low abundance of tricyclic terpanes geochemical correlation with four petroleums from the junggar tarim and turpan basins strongly suggests that the jurassic coaly deposits and their lacustrine equivalents downdip are petroleum source rocks sterane and hopane distributions of petroleums and extracts of their putative jurassic source rock are similar and can be easily distinguished from published distributions of these compounds in other source rock layers additional correlation parameters include high pristane phytane low abundance or lack of tricyclic terpanes but similar distributions where present and lack of gammacerane with one exception and carotanes compounds that characterize permian and ordovician source rocks and their respective petroleums pyrolysis gas chromatography of selected jurassic samples s ggests that they possess potential for liquid hydrocarbon generation expulsion of c15 hydrocarbons from jurassic source rocks appears likely despite the traditional view that bituminous coals are incapable of expelling long chain hydrocarbons end page 929

deformation across the western quetico subprovince and adjacent boundarl regions in minnesota north to northwest directed crustal shortening across the western quetico subprovince and its boundary regions produced a complex deformation sequence within the quetico belt and resulted in concentrated zones of dextral ductile shear in the boundary regions within the adjacent greenstone granite terranes in this paper we review and introduce new data on the regional deformation features and their geometries and discuss the history of generation of these features we attribute the deformation sequence to differential partitioning of shortening and shear strains during dextral transpression associated with oblique convergence and accretion along the southern margin of the superior province the turbiditic wacke in the western quetico subprovince now typically amphibolite facies schist and migmatite underwent an early deformation stage that included recumbent folding f1 and the generation of an s1 bedding parallel foliation this event is most evident along the northern and southern boundaries of the

kinetics of oil generation from brackish lacustrine source rocks in the southern bohai sea east china abstract oil generation c14 hydrocarbons of three type ii kerogen samples isolated from brackish lacustrine mudstones from palaeogene strata ed3 es1 es3 in the southern bohai sea was simulated by closed system gold tube experiments in addition a series of complementary analyses rock eval pyrolysis total organic carbon vitrinite reflectance trace element x ray diffraction and flash pyrolysis gas chromatography mass spectrometry were also performed to identify the bulk geochemistry palaeo environment and chemical composition of the kerogen the aim of this study was to achieve a better understanding of the kinetics of oil generation from lacustrine source rocks in the southern bohai sea the results show that the three samples are type ii source rocks deposited in similar palaeo environments hot and arid climates anoxic conditions and brackish water in shallow to semi deep lakes with consequent similarity in the chemical compositions of their kerogens the organic matter inputs are predominantly composed of lacustrine microalgae with a relatively small contribution from land plants the activation energies of oil generation from these samples show a range of 44 52 kcal mol with a frequency factor varying from 1 116 1014 to 1 274 1014 s 1 due to the similar palaeo environments and chemical composition samples in this study exhibit strong consistencies in kinetic parameters transformation ratio tr evolution curves of oil generation from the three samples calculated under a linear heating rate 3 k ma exhibit a slight difference which varies within 4 c at a given tr due to the great similarities of the three kinetic models an average kinetic model for the type ii brackish lacustrine source rocks in the southern bohai sea was established this model integrates the characteristics of the three kinetic models and is still dominated by activation energy of 52 kcal mol the geological temperature of the oil generation phase for the average model in the southern bohai sea is from 92 to 137 c

correlation of early recumbent and younger upright folding across the boundary between an archean gneiss belt and greenstone terrane northeastern minnesota correlation of an f 1 recumbent fold and an upright f 2 antiform across the boundary between an archean migmatite terrane and the adjacent volcanic plutonic belt indicates a common tectonic evolution for both terranes since the earliest stages of folding the local boundary between amphibolite facies schists and migmatites of the southern vermilion granitic complex vgc and low grade metagraywackes of the adjacent vermilion district is marked by nearly vertical dip slip faulting along the east trending axial trace of a regional f 2 antiform the migmatites in the southern vgc have been folded into s symmetry folds that mark the northern limb of the major antiform these folds are correlated with f 2 folds of z symmetry on the southern limb of the fold in adjacent downfaulted rocks of the vermilion district structural facing near the boundary between the two subprovinces is downward on both limbs of the major f 2 structure which is interpreted to be part of the lower overturned limb of a large scale f 1 recumbent fold a change to upright facing strata farther south indicates a crossing onto the upper limb of the structure the f 1 folding is tentatively attributed to gravitational spreading off the southern margin of the rising lac la croix granite of the east central vgc

flash pyrolysis of kerogens from algal rich oil shales from the eocene huadian formation ne china abstract the hydrocarbon composition of the kerogen fractions of two samples hd 20 and hd 21 from oil shale layer 4 in the eocene huadian formation ne china were investigated by analytical flash pyrolysis 650 c 10 s followed by gas chromatography mass spectrometry py gc ms organic petrography showed that the two kerogens were almost entirely derived from algal remains but contained very different algal maceral compositions with 40 of the macerals in hd 20 being of macroalgal origin that were not present in hd 21 py gc ms yielded high concentrations of n alkanes from both kerogens but with different molecular weight profiles due to the different algal contributors to the two kerogen samples the hydrocarbon pyrolysates generated at 650 c from hd 21 in which the green microalga botryococcus braunii was identified showed a higher proportion of longer chain alkanes and alkenes presumably from cracking of the botryococcus algaenan we also identified a c40 monoaromatic lycopane derivative which was absent in the hd 20 the high hydrocarbon potential of both kerogens can be attributed to common microalgal sources whereas the macroalgae which is abundant in hd 20 makes only a minor contribution to the hydrocarbon products

variations in geochemical character of asphaltenes from a source rock in contact with an oil reservoir abstract asphaltenes are suspected to be essentially small solubilized less condensed kerogen moities these materials should then be excellent for use in evaluation of source environments and as source rock oil correlation parameters this study compares chemical and isotopic compositions of asphaltenes extracted from a 100 m continuous core through the kimmeridge shale of the north sea with associated resins nos as well as with both resins and asphaltenes from the oil of the adjacent sandstone reservoir which is in contact with the shale through gel permeation chromatography two distinct classifications of molecular weight mw distributions for the asphaltenes of the source rock extracts are observed 1 a high mw range 5000 30000 daltons which is associated with enriched carbon isotopic signatures 25 to 26 and 2 a lower mw range 1500 5000 daltons which correlates with more common samples having depleted isotopic compositions 28 to 30 in similar fashion the high mw asphaltenes show increased concentrations of longer chain length alkyl groups nc22 and greater which are released through pyrolysis gas chromatography resins associated with the high mw asphaltenes have a greater high mw content than resins from the more common kerogens coincidences of high carbonate are also noted in most isotopically anomolous samples these data indicate a changing depositional environment probably associated with an increasing bacterial component and recycling an increase in mw of asphaltenes in the reservoir oil was observed and suggests further condensation of these structures may occur in the reservoir following migration or increased level of maturity carbon isotopic compositions of specific mw fractions of resins and asphaltenese support the hypothesis that high mw asphaltenes and resins are precursors in low mw asphaltene and resin generation

transpression in slates along the margin of an archean gneiss belt northern ontario magnetic fabrics and petrofabrics archean slates along the northern boundary of the quetico subprovince of the superior province show marked variations of the structural facing direction within coplanar primary cleavage surfaces these are interpreted as being due to sheath folds near the faulted east west boundary of the slates with the metavolcanic wabigoon belt sheath folds with axial traces nearly parallel to the belt boundary are macroscopic primary and isoclinal and are believed to result from pervasive dextral transpression of the northern margin of the quetico subprovince magnetic fabrics confirm the presence of a single penetrative flattening tectonic microfabric and considerable north south shortening on the scale of hand specimens and outcrops the magnetic fabric is due to the alignment of metamorphic sheet silicates with a subordinate contribution due to the preferred dimensional orientation of detrital magnetite grains in some low strain environments at the hinges of sheath folds and at the sandy bases of graded beds r

an organic geochemical study of bitumens and their potential source rocks from the south pennine orefield central england abstract bitumens associated with pb zn mineralisation hosted by upper dinantian limestones in the south pennine orefield derbyshire central england were characterised in terms of maturity as well as source correlation parameters and compared with hydrocarbons from the east midlands oilfield and bitumens from the cheshire basin potential source rocks from within the dinantian sequence and from the lower namurian mudstones of adjacent carboniferous sedimentary basins were characterised in a similar fashion the bitumens from both derbyshire and cheshire show a range of effects due to biodegradation and water washing from partial to complete removal of n alkanes isoprenoids and polyaromatic hydrocarbons the bitumen oil suite derbyshire bitumens cheshire bitumens and east midlands oils show mature biological marker distributions whilst the derbyshire bitumens and east midlands oils generally correlate well with each other bitumens from cheshire show distinct differences on the grounds of maturity and source correlation biological marker characteristics it is possible to suggest likely source rocks for the derbyshire bitumens and east midlands oils using a multiparameter approach lower namurian mudstones from the widmerpool gulf along with those from the gainsborough and goyt troughs are not regarded as source rocks the lower namurian mudstones from the edale gulf correlated with the east midlands oils and derbyshire bitumens on the basis of a restricted number of biological marker compound classes bulk and molecular maturity parameters also indicate that these particular formations could have generated hydrocarbons more local contributions to the derbyshire bitumens may have been made by some of the organic rich mudstones within the dinantian succession

evolution of an archean subprovince boundary a sedimentological and structural study of part of the wabigoon quetico boundary in northern ontario a prograded clastic wedge represented by formation to group scale units of metasedimentary strata in the beardmore geraldton terrane developed in a transitional zone at the southern margin of a