Ultraviolet ion chamber measurements of the solar minimum brightness temperature     

J. H. Carver  B. H. Horton  G. W. A. Lockey  Bryan Rofe 《Solar physics》1972,27(2):347-353

The solar ultraviolet flux in the wavelength bands 1580–1640 Å and 1430–1470 Å (FWHM) has been measured using photon ion chambers carried on the satellite WRESAT I (1967-118A). These observations of the integrated ultraviolet flux from the entire disk indicate a value of (4570 ± 50) K for the solar temperature minimum. The results are compared with other estimates of the minimum value of the solar brightness temperature.Died August, 1971.  相似文献   

PALEOGENE(?) DEPOSYSTEMS AND BASIN EVOLUTION IN THE EASTERN TIBETAN PLATEAU: NANGQIAN AND XIALAXIU BASINS   总被引：1，自引：0，他引：1  

Brian K. Horton    Zhou Jiangyu  Matt S. Spurlin  An Yin  Wang Jianghai 《地学前缘》2000,(Z1)

PALEOGENE(?) DEPOSYSTEMS AND BASIN EVOLUTION IN THE EASTERN TIBETAN PLATEAU: NANGQIAN AND XIALAXIU BASINS  相似文献   

Insights into environmental drivers of acoustic angular response using a self-organising map and hierarchical clustering     

James Daniell  Justy Siwabessy  Scott Nichol  Brendan Brooke 《Geo-Marine Letters》2015,35(5):387-403

  相似文献   

Shelf habitat distribution as a legacy of Late Quaternary marine transgressions: A case study from a tropical carbonate province     

Scott L. Nichol  Brendan P. Brooke 《Continental Shelf Research》2011,31(17):1845-1857

The legacy of multiple marine transgressions is preserved in a complex morphology of ridges, mounds and reefs on the Carnarvon continental shelf, Western Australia. High-resolution multibeam sonar mapping, underwater photography and sampling across a 280 km² area seaward of the Ningaloo Coast World Heritage Area shows that these raised features provide hardground habitat for modern coral and sponge communities. Prominent among these features is a 20 m high and 15 km long shore-parallel ridge at 60 m water depth. This ridge preserves the largely unaltered form of a fringing reef and is interpreted as the predecessor to modern Ningaloo Reef. Landward of the drowned reef, the inner shelf is covered by hundreds of mounds (bommies) up to 5 m high and linear ridges up to 1.5 km long and 16 m high. The ridges are uniformly oriented to the north-northeast and several converge at their landward limit. On the basis of their shape and alignment, these ridges are interpreted as relict long-walled parabolic dunes. Their preservation is attributed to cementation of calcareous sands to form aeolianite, prior to the post-glacial marine transgression. Some dune ridges abut areas of reef that rise to sea level and are highly irregular in outline but maintain a broad shore-parallel trend. These are tentatively interpreted as Last Interglacial in age. The mid-shelf and outer shelf are mostly sediment covered with relatively low densities of epibenthic biota and have patches of low-profile ridges that may also be relict reef shorelines. An evolutionary model for the Carnarvon shelf is proposed that relates the formation of drowned fringing reefs and aeolian dunes to Late Quaternary eustatic sea level.  相似文献   

The application of foraminifera to reconstruct the rate of 20th century sea level rise, Morbihan Golfe, Brittany, France     

Veronica Rossi  Benjamin P. Horton  Eduardo Leorri  Bruce C. Douglas 《Quaternary Research》2011,75(1):24-35

Foraminiferal assemblages preserved within salt-marsh sediment can provide an accurate and precise means to reconstruct relative sea level due to a strong relationship with elevation, which can be quantified using a transfer function. We collected a set of surface samples from two salt marshes in the Morbihan Golfe, France to determine foraminiferal distribution patterns. Dominant taxa included Jadammina macrescens, Trochammina inflata, Haplophragmoides spp. and Miliammina fusca. We developed a foraminifera-based transfer function using a modern training set of 36 samples and 23 species. The strong relationship between observed and predicted values (r²_jack = 0.7) indicated that foraminiferal distribution is primarily controlled by elevation with respect to the tidal frame and precise reconstructions of former sea level are possible (RMSEP_jack = 0.07 m). The application of the transfer function to a short salt-marsh core (0.32 m) allowed the reconstruction of former sea levels, which were placed in a chronological framework using short-lived radionuclides (²¹⁰Pb and ¹³⁷Cs). The agreement between the foraminifera-based sea level curve and the Brest tide-gauge record confirms the reliability of transfer function estimates and the validity of this methodology to extend sea level reconstructions back into the pre-instrumental period. Both instrumental and microfossil records suggest an acceleration of sea level rise during the 20th century.  相似文献   

Chlorins in mid-Cretaceous black shales of the Demerara Rise: The oldest known occurrence     

Christopher K. Junium  Brendan J. KeelyKatherine H. Freeman  Michael A. Arthur 《Organic Geochemistry》2011,42(7):856-859

Liquid chromatography, multi-stage mass spectrometry (LC-MSⁿ) of acetone extracts confirms the presence of mesochlorophyllone in the mid-Cretaceous black shales of Demerara Rise. This finding represents molecular confirmation of the oldest primary chlorins in the geologic record and is evidence for a chlorophyll a source for bicycloalkanoporphyrins in the Demerara Rise black shales.  相似文献   

Bait-attending fauna of the Kermadec Trench, SW Pacific Ocean: Evidence for an ecotone across the abyssal-hadal transition zone   总被引：1，自引：0，他引：1  

A.J. Jamieson  N.M. KilgallenA.A. Rowden  T. FujiiT. Horton  A.-N. LörzK. Kitazawa  I.G. Priede 《Deep Sea Research Part I: Oceanographic Research Papers》2011,58(1):49-62

The bait-attending fauna of the abyssal-hadal transition zone of the Kermadec Trench, SW Pacific Ocean (4329-7966 m), was investigated using a baited camera and a trap lander. The abyssal stations (4329-6007 m) revealed a typical scavenging fish community comprising macrourids and synaphobranchid eels, as well as natantian decapods. At the hadal depths of 7199 and 7561 m, the endemic liparid Notoliparis kermadecensis was observed aggregating at the bait reaching surprisingly high numbers of 5 and 13, respectively. A total of 3183 invertebrate samples were collected (mean deployment time=16 h) of which 97.8% were of the order Amphipoda (nine families, 16 species). Ten of the amphipod species represent new distributional records for the Kermadec Trench and the New Zealand Exclusive Economic Zone; this includes the shallowest known record of the endemic hadal amphipod Hirondellea dubia (6000, 6007 m). Using amphipods to statistically examine the compositional change across the abyssal-hadal boundary, an ecotone between depths <6007 and >6890 m was found, indicating that there is an ecologically distinct bait-attending fauna in this trench.  相似文献   

Assessing changes in nutrient status in the Richmond River estuary,Australia, using paleolimnological methods   总被引：1，自引：0，他引：1  

Brendan Logan  Kathryn H. Taffs  Bradley D. Eyre  Atun Zawadski 《Journal of Paleolimnology》2011,46(4):597-611

Eutrophication from nutrient over-enrichment is a serious problem for the coastal zone and the estuarine environment globally. Australian estuaries are generally oligotrophic, but assessing whether they are becoming more eutrophic over time is inhibited by a lack of long-term monitoring data. The Richmond River, Australia, provided an ideal example of an estuary under anthropogenic pressure where the use of paleoecological techniques may potentially be used to reconstruct changes in nutrient status over time. Five cores were extracted from depositional areas in the Richmond River, and subjected to paleo-magnetic profiling and loss-on-ignition testing to ensure the core of greatest integrity was selected for further analytical work. Results from diatom and stable isotope analyses combined with ²¹⁰Pb and AMS ¹⁴C dating show a strong indication that the total phosphorus levels in the Richmond River have fluctuated since 1940. Evidence also suggests that these fluctuations are most likely a function of climate. This study has successfully applied paleolimnological techniques to the estuarine environment to produce information that can be used by environmental managers to aid decision making in relation to nutrient control for the Richmond River. Further work using paleolimnological techniques should be aimed at the extraction of a core containing diatoms that pre-date European settlement and include analyses of specific lipids and fatty acid biomarkers.  相似文献   

Thermal behavior of ferric selenite hydrates (Fe₂(SeO₃)₃·3H₂O,Fe₂(SeO₃)₃·5H₂O) and the water content in the natural ferric selenite mandarinoite     

Astrid Holzheid  Marina V. Charykova  Vladimir G. Krivovichev  Brendan Ledwig  Elena L. Fokina  Ksenia L. Poroshina  Natalia V. Platonova  Vladislav V. Gurzhiy 《Chemie der Erde / Geochemistry》2018,78(2):228-240

Any progress in our understanding of low-temperature mineral assemblages and of quantitative physico-chemical modeling of stability conditions of mineral phases, especially those containing toxic elements like selenium, strongly depends on the knowledge of structural and thermodynamic properties of coexisting mineral phases. Interrelation of crystal chemistry/structure and thermodynamic properties of selenium-containing minerals is not systematically studied so far and thus any essential generalization might be difficult, inaccurate or even impossible and erroneous. Disagreement even exists regarding the crystal chemistry of some natural and synthetic selenium-containing phases. Hence, a systematic study was performed by synthesizing ferric selenite hydrates and subsequent thermal analysis to examine the thermal stability of synthetic analogues of the natural hydrous ferric selenite mandarinoite and its dehydration and dissociation to unravel controversial issues regarding the crystal chemistry. Dehydration of synthesized analogues of mandarinoite starts at 56–87?°C and ends at 226–237?°C. The dehydration happens in two stages and two possible schemes of dehydration exist: (a) mandarinoite loses three molecules of water in the first stage of the dehydration (up to 180?°C) and the remaining two molecules of water will be lost in the second stage (>180?°C) or (b) four molecules of water will be lost in the first stage up to 180?°C and the last molecule of water will be lost at a temperature above 180?°C. Based on XRD measurements and thermal analyses we were able to deduce Fe₂(SeO₃)₃·(6-x)H₂O (x?=?0.0–1.0) as formula of the hydrous ferric selenite mandarinoite. The total amount of water apparently affects the crystallinity, and possibly the stability of crystals: the less the x value, the higher crystallinity could be expected.  相似文献   

Evidence for temporally coherent increases in the abundance of small Discostella (Bacillariophyceae) species over the past 200 years among boreal lakes from the Experimental Lakes Area (Canada)     

Wiltse  Brendan  Mushet  Graham R.  Paterson  Andrew M.  Cumming  Brian F. 《Journal of Paleolimnology》2022,67(3):273-287

Journal of Paleolimnology - Increased relative abundances and accumulation rates of the small, centric diatom Discostella have been recorded in numerous paleolimnological investigations of north...  相似文献