The contamination of cuttings and side wall core (SWC) samples in the Bambra 2 well by drilling mud additives and natural hydrocarbons may cause Rock Eval T max (℃) data to be suspect, and affect its uti...The contamination of cuttings and side wall core (SWC) samples in the Bambra 2 well by drilling mud additives and natural hydrocarbons may cause Rock Eval T max (℃) data to be suspect, and affect its utility in the assessment of thermal maturity. The Rock Eval results of 284 cuttings samples, 31 side wall core samples and conventional core samples from the Jurassic Cretaceous sedimentary sequences in the Bambra 2 well are presented in this paper. Significantly lower T max values from cuttings samples compared with T max values from conventional core samples and solvent extracted SWC samples, from the deeper and higher maturity interval, are thought to have been caused by contamination by diesel and other drilling mud additives. The cuttings samples in the Barrow Group of Cretaceous may be contaminated by natural hydrocarbons, resulting their T max values to be 2-10 ℃ lower than a regularly increased T max trend from core samples. This study indicates that more reliable Rock Eval T max data are obtained from the conventional core samples and solvent extracted SWC samples. This study also indicates that the T max values from some SWC samples were also affected by free hydrocarbons, due to the use of diesel as a mud additive as well.展开更多
Precipitation samples collected at Point Barrow, Alaska in the August and September of 1994 was analyzed for pH, conductivity and all major ions. A mean pH value of 5.53 was gained, and the samples' conductiv...Precipitation samples collected at Point Barrow, Alaska in the August and September of 1994 was analyzed for pH, conductivity and all major ions. A mean pH value of 5.53 was gained, and the samples' conductivity showed no linear correlation with its acidity, which did not agree to the similar work results on the Qinghai Tibet Plateau. Cl - and Na + were found to originate mainly with seasalt. The concentrations of SO 2- 4 varied from event to event. But the exSO 2- 4 concentrations remained small, which indicated less anthropogenic effect on the environment at the site.展开更多
This paper deals with the features and distribution of chemical elements in the Borecore AB 67 (60 cm long, it covered a time span of past 450 a) from Elson Lagoon in Barrow,Arctic Alaska. The analysing data show ...This paper deals with the features and distribution of chemical elements in the Borecore AB 67 (60 cm long, it covered a time span of past 450 a) from Elson Lagoon in Barrow,Arctic Alaska. The analysing data show that concentration of major elements,trace elements,rare and rare earth elements are quite different between the upper part (0 20 cm) and the lower part (20 60 cm). And the correlation between contents of clay and organic material and concentration of chemical elements are discussed. Based on the characters of sediment geochemistry of Borecore AB 67,the history of climatic and environmental changes in Barrow in the past 450 a can be reconstracted as follows: 1) Relatively cold and dry with low sea level stage occurred prior to 1740 A.D.; 2) It was becoming warm accompanied by transgression from 1740 A.D. to 1827 A.D.; 3) From 1827 A.D. to 1994 A.D.(0 20 cm),it was fluctuated warming accompanied by continuous transgression,in this period relatively cold appeared around 1935 A.D. and 1969 A.D..展开更多
A total of 48 samples from the core AB 67 at Barrow are analyzed for 25 grain size items and 44 geochemical items. Q mode factor analysis applied to these data yielded 4 factors. Mapping of there factor showed their...A total of 48 samples from the core AB 67 at Barrow are analyzed for 25 grain size items and 44 geochemical items. Q mode factor analysis applied to these data yielded 4 factors. Mapping of there factor showed their close affinity to sedimentary environment; these core sedimentary rate, precipitation, sea level change, annual temperature. Paleoenvironmentary transfer functions were defined to estimate mean annual temperature and annual precipitation from corelationship between 5 samples at core top and observation record from Barrow Meteorology Observatory. Sedimentary rate was determinated from dating by 210 Pb and several environment events, and sea level from changes of sedimentary phase. The reconstructed temperature and precipitation curves show that Barrow climate is colder and drier in the 16th and the 17th century, temperature rose up and precipitation fluctuated sharply in the 18th and the 19th century, these two changes are greater in the 20th century. The reconstructed temperature curves agree with the variation of assemblages of micropaleontology.展开更多
A temperature record from a lake core reveals that it becomes warming at average rate of 0 4 ℃ per century in the past 400 a at Barrow, but it turns cold in the past 200 a. Maximum entropy spectra analysis shows tha...A temperature record from a lake core reveals that it becomes warming at average rate of 0 4 ℃ per century in the past 400 a at Barrow, but it turns cold in the past 200 a. Maximum entropy spectra analysis shows that in the temperature fluctuations there are cycles of 33, 40, 29 a and about 90 a at Barrow. According to statistics and entropy analysis of monthly mean temperature from Barrow Meteorological Observatory in 1921 1994, there are cycles of 4, 6, 14, 16 months and 3, 4, 7, 10 a in the recent temperature change.展开更多
Based on the field measurements in Barrow, Alaska within the period of April-May 2015, we investigate the sources and variations of elemental carbon(EC) and organic carbon(OC) in the surface layer of snowpack on sea i...Based on the field measurements in Barrow, Alaska within the period of April-May 2015, we investigate the sources and variations of elemental carbon(EC) and organic carbon(OC) in the surface layer of snowpack on sea ice, and estimate their effects on the sea ice albedo. Results show that the snow OC in Barrow are from natural sources(e.g. terrestrial higher plants and micro-organisms) mainly, as well as biomass burning(e.g. forest fires and straw combustion) as an important part. Both EC and OC can accumulate at the snow surface with snow melt. The variations in EC and OC and liquid water content in the snow layer are well consistent during the snow-melting period. A higher rate of snow melt implied a more efficient enrichment of EC and OC. In the last phase of snow melt, the concentration increased to a maximum of 16.2 ng/g for EC and 128 ng/g for OC, which is ~10 times larger than those before snow melt onset. Except for the dominant influence of melt amplification mechanism, the variation in concentrations of EC and OC could be disturbed by the air temperature fluctuation and snowfall. Our study indicates that the lightabsorbing impurities contributed 1.6%-5.1% to the reduction in sea ice albedo with melt during the measurement period. The significant period oflight-absorbing impurities influencing on sea ice albedo begins with the rapid melting of overlying snow and ends before the melt ponds formed widely, which lasted for about 10 days in Barrow, 2015.展开更多
Investigation of plant morphological features, pollen, and habitat have been made for two shrub species from Barrow, Alaska, namely Dryas integrifoila M. Vahl and Salix rotundifolia Trautv., both of which are endemic ...Investigation of plant morphological features, pollen, and habitat have been made for two shrub species from Barrow, Alaska, namely Dryas integrifoila M. Vahl and Salix rotundifolia Trautv., both of which are endemic to the Arctic floristic area. The former species has small lanceolate or plate leaves, whereas the latter has rounded leaves with distinct veins, rich in vitamin C. Both have dwarf and sprawling habits. Pollen studies showed that the pollen grains of the two species are spheroidal to sub-spheroidal or prolate. The type of aperture was tricolporate; pollen size 26.3-31.3 μm; ornamentation finely reticulate under a light microscope （LM） and strlate-reticulate under a scanning electron microscope （SEM） for D. integrafoila and finely reticulate under the LM and SEM for S. rotundifolia. Comparisons were made between the pollen from the same species from Arctic collections with those from China and Japan. Investigation of pollen morphology of tundra plants can provide significant data for comparative studies of fossil pollen and for the reconstruction of paleovegetation and paleoclimate in the Barrow area.展开更多
文摘The contamination of cuttings and side wall core (SWC) samples in the Bambra 2 well by drilling mud additives and natural hydrocarbons may cause Rock Eval T max (℃) data to be suspect, and affect its utility in the assessment of thermal maturity. The Rock Eval results of 284 cuttings samples, 31 side wall core samples and conventional core samples from the Jurassic Cretaceous sedimentary sequences in the Bambra 2 well are presented in this paper. Significantly lower T max values from cuttings samples compared with T max values from conventional core samples and solvent extracted SWC samples, from the deeper and higher maturity interval, are thought to have been caused by contamination by diesel and other drilling mud additives. The cuttings samples in the Barrow Group of Cretaceous may be contaminated by natural hydrocarbons, resulting their T max values to be 2-10 ℃ lower than a regularly increased T max trend from core samples. This study indicates that more reliable Rock Eval T max data are obtained from the conventional core samples and solvent extracted SWC samples. This study also indicates that the T max values from some SWC samples were also affected by free hydrocarbons, due to the use of diesel as a mud additive as well.
文摘Precipitation samples collected at Point Barrow, Alaska in the August and September of 1994 was analyzed for pH, conductivity and all major ions. A mean pH value of 5.53 was gained, and the samples' conductivity showed no linear correlation with its acidity, which did not agree to the similar work results on the Qinghai Tibet Plateau. Cl - and Na + were found to originate mainly with seasalt. The concentrations of SO 2- 4 varied from event to event. But the exSO 2- 4 concentrations remained small, which indicated less anthropogenic effect on the environment at the site.
文摘This paper deals with the features and distribution of chemical elements in the Borecore AB 67 (60 cm long, it covered a time span of past 450 a) from Elson Lagoon in Barrow,Arctic Alaska. The analysing data show that concentration of major elements,trace elements,rare and rare earth elements are quite different between the upper part (0 20 cm) and the lower part (20 60 cm). And the correlation between contents of clay and organic material and concentration of chemical elements are discussed. Based on the characters of sediment geochemistry of Borecore AB 67,the history of climatic and environmental changes in Barrow in the past 450 a can be reconstracted as follows: 1) Relatively cold and dry with low sea level stage occurred prior to 1740 A.D.; 2) It was becoming warm accompanied by transgression from 1740 A.D. to 1827 A.D.; 3) From 1827 A.D. to 1994 A.D.(0 20 cm),it was fluctuated warming accompanied by continuous transgression,in this period relatively cold appeared around 1935 A.D. and 1969 A.D..
文摘A total of 48 samples from the core AB 67 at Barrow are analyzed for 25 grain size items and 44 geochemical items. Q mode factor analysis applied to these data yielded 4 factors. Mapping of there factor showed their close affinity to sedimentary environment; these core sedimentary rate, precipitation, sea level change, annual temperature. Paleoenvironmentary transfer functions were defined to estimate mean annual temperature and annual precipitation from corelationship between 5 samples at core top and observation record from Barrow Meteorology Observatory. Sedimentary rate was determinated from dating by 210 Pb and several environment events, and sea level from changes of sedimentary phase. The reconstructed temperature and precipitation curves show that Barrow climate is colder and drier in the 16th and the 17th century, temperature rose up and precipitation fluctuated sharply in the 18th and the 19th century, these two changes are greater in the 20th century. The reconstructed temperature curves agree with the variation of assemblages of micropaleontology.
文摘A temperature record from a lake core reveals that it becomes warming at average rate of 0 4 ℃ per century in the past 400 a at Barrow, but it turns cold in the past 200 a. Maximum entropy spectra analysis shows that in the temperature fluctuations there are cycles of 33, 40, 29 a and about 90 a at Barrow. According to statistics and entropy analysis of monthly mean temperature from Barrow Meteorological Observatory in 1921 1994, there are cycles of 4, 6, 14, 16 months and 3, 4, 7, 10 a in the recent temperature change.
基金supported by the Ministry of Science and Technology of China(MOST, 2013CBA01804)the National Nature Science Foundation of China (41425003,41401079, 41476164 and 41625014)+2 种基金the key project of CAMS:Research on the Key Processes of Cryospheric Rapid Changes (KJZD-EW-G03)the Opening Founding of State Key Laboratory of Cryospheric Sciences(SKLCSOP-2016-03)the State Key Laboratory of Cryospheric Sciences (SKLCS-ZZ-2017)
文摘Based on the field measurements in Barrow, Alaska within the period of April-May 2015, we investigate the sources and variations of elemental carbon(EC) and organic carbon(OC) in the surface layer of snowpack on sea ice, and estimate their effects on the sea ice albedo. Results show that the snow OC in Barrow are from natural sources(e.g. terrestrial higher plants and micro-organisms) mainly, as well as biomass burning(e.g. forest fires and straw combustion) as an important part. Both EC and OC can accumulate at the snow surface with snow melt. The variations in EC and OC and liquid water content in the snow layer are well consistent during the snow-melting period. A higher rate of snow melt implied a more efficient enrichment of EC and OC. In the last phase of snow melt, the concentration increased to a maximum of 16.2 ng/g for EC and 128 ng/g for OC, which is ~10 times larger than those before snow melt onset. Except for the dominant influence of melt amplification mechanism, the variation in concentrations of EC and OC could be disturbed by the air temperature fluctuation and snowfall. Our study indicates that the lightabsorbing impurities contributed 1.6%-5.1% to the reduction in sea ice albedo with melt during the measurement period. The significant period oflight-absorbing impurities influencing on sea ice albedo begins with the rapid melting of overlying snow and ends before the melt ponds formed widely, which lasted for about 10 days in Barrow, 2015.
文摘Investigation of plant morphological features, pollen, and habitat have been made for two shrub species from Barrow, Alaska, namely Dryas integrifoila M. Vahl and Salix rotundifolia Trautv., both of which are endemic to the Arctic floristic area. The former species has small lanceolate or plate leaves, whereas the latter has rounded leaves with distinct veins, rich in vitamin C. Both have dwarf and sprawling habits. Pollen studies showed that the pollen grains of the two species are spheroidal to sub-spheroidal or prolate. The type of aperture was tricolporate; pollen size 26.3-31.3 μm; ornamentation finely reticulate under a light microscope （LM） and strlate-reticulate under a scanning electron microscope （SEM） for D. integrafoila and finely reticulate under the LM and SEM for S. rotundifolia. Comparisons were made between the pollen from the same species from Arctic collections with those from China and Japan. Investigation of pollen morphology of tundra plants can provide significant data for comparative studies of fossil pollen and for the reconstruction of paleovegetation and paleoclimate in the Barrow area.
