Authorship,Collaboration, and Gender: Fifteen Years of Publication Productivity in Selected Geography Journals

In academia, publication productivity, defined as the number of peer-reviewed articles published and the frequency of citations, is a primary factor in the assessment of tenure and promotion. One of the most cited gender differences in academia is the “productivity puzzle,” which suggests that women publish less than men, thereby affecting every aspect of a woman's academic career. Peer-reviewed articles published in the Annals of the Association of American Geographers (Annals) and The Professional Geographer (PG) between 1995 and 2006, and in four subdisciplinary journals between 2005 and 2009, as well as citation reports, were used to explore whether gender differences are present in publication productivity. Gender differences were evident in the proportion of women authors, the frequency of collaboration, and the number of citations across a broad range of prestigious geographic journals. For all journals studied, women were underrepresented, especially in the authorship positions that equate to notions of respect and merit. Although the number of collaborative articles increased during the study period, single-authored papers are the dominant mode of publication for both men and women for most geographic journals. The authorship patterns for frequently cited articles generally mirror those for all articles. Because the frequency of collaborative publication was high for women, the dual trends of a general increase in publication collaboration and increasing participation of women in academic geography bodes well for increased female productivity as it relates to publishing. Nevertheless, it is important to note that, currently, males as lead or single authors represent the predominant voice of geography within the journals examined in this study.     

SUMMER MEASUREMENTS OF DISSOLVED ION CONCENTRATIONS IN ALPINE STREAMS,BLANCA PEAK REGION,COLORADO*

Chemical weathering is commonly assumed to be negligible in the denudation of alpine landscapes. Spot samples of dissolved ions from alpine streams on the Blanca Massif had minimum average concentrations in 1978 of 35.53 ppm (range: 14.9–75.6 ppm) and in 1979, 20.23 ppm (range: 7.35–35.0 ppm). Correlations between the variation in the concentration of dissolved ions (silica, pH, and minimum ion concentration) and the elevations and drainage-basin areas of sample sites were significant at the 0.05 level.     

3D seismic imaging of a Tertiary Dyke Swarm in the Southern North Sea,UK

We use three‐dimensional (3D) seismic reflection and magnetic data to interpret and describe the 3D geometry of igneous dykes in the southern North Sea. The dykes were emplaced into Paleozoic and Mesozoic sediments and have a common upper termination in Early Tertiary sediments. We interpret the dykes to be part of the British Tertiary volcanic province and estimate the age of the dykes to be 58 Ma. The dykes are characterized by a narrow 0.5–2 km wide vertical disturbance of seismic reflections that have linear plan view geometry. Negative magnetic anomalies directly align with the vertical seismic disturbance zones and indicate the presence of igneous material. Linear coalesced collapse craters are found above the dykes. The collapse craters have been defined and visualized in 3D. Collapse craters have formed above the dyke due to the release of volatiles at the dyke tip and resulting volume loss. Larger craters have potentially formed due to explosive phreatomagmatic interaction between magma and pore water. The collapse craters are a new Earth analogue to Martian pit chain craters.     

The nation-state and the city: introduction to a debate

In recent years, the urban political landscape has become infused with a potent and incendiary mixture of popular-democratic, anti-globalisation, and separatist rhetoric. One central process driving this has been the problematic relations between the nation-state and the city. This Debates and Interventions forum aims to prompt a debate about where the city should be situated intellectually in respect of the nation-state. Four questions are addressed: (1) How do contemporary processes of urban development reflect changing national geopolitical priorities? (2) To what extent are struggles around immigration, citizenship and recognition conducted within cities rather than around the nation-state? (3) To what degree does the city (as e.g. a physical form, social environment or discourse) help to mobilise, propel and/or contest this new urban politics? And (4) Is the concept of a “post-national” global order appropriate for understanding the city and urban politics today?     

Uranium and Thorium Concentration and Isotopic Composition in Five Glass (BHVO‐2G,BCR‐2G,NKT‐1G,T1‐G,ATHO‐G) and Two Powder (BHVO‐2, BCR‐2) Reference Materials

Here we report uranium and thorium isotopic ratios and elemental concentrations measured in solid reference materials from the USGS (BHVO‐2G, BCR‐2G, NKT‐1G), as well as those from the MPI‐DING series (T1‐G, ATHO‐G). Specifically created for microanalysis, these naturally‐sourced glasses were fused from rock powders. They cover a range of compositions, elemental concentrations and expected isotopic ratios. The U‐Th isotopic ratios of two powdered source materials (BCR‐2, BHVO‐2) were also characterised. These new measurements via multi‐collector thermal ionisation mass spectrometry and multi‐collector inductively coupled plasma‐mass spectrometry can now be used to assess the relative performance of techniques and facilitate comparison of U‐Th data amongst laboratories in the geoscience community for in situ and bulk analyses.     

Early Devensian sediments and palaeovenvironmental evidence from the excavations at the Royal Oak Portal Paddington,West London,UK

This paper discusses the results of the investigation of Pleistocene sediments at the Royal Oak Portal (ROP) site on the new Crossrail scheme near Paddington Station, London. The site was sampled and recorded in May 2011 by archaeologists from Oxford Archaeology commissioned by Crossrail Ltd. The investigation revealed a sedimentary sequence associated with cool climate waterlain deposition towards the edge of the River Westbourne floodplain. During excavation an assemblage of around 100 identifiable large mammal bones was recovered, dating to the Late Pleistocene. The major concentration of bones, from bison and reindeer, was located and excavated from a shallow sequence of sediments. Analysis of the bones indicates that they represent a natural death assemblage, scavenged and subsequently disarticulated, transported by water, exposed and further dispersed and broken by trampling. The site is of regional and national importance because the assemblage derives from a well-constrained geological context, with associated dating evidence suggesting accumulation during the later parts of Marine Isotope Stage (MIS) 5 and continuing within MIS 4. The site is also of significance because it is one of a growing number of recently discovered sites away from the main fluvial archive for the British Middle and Upper Pleistocene. These sites have the potential to add significantly to our understanding of parts of the Pleistocene record that remain difficult to document through the investigation of the more active systems associated with major rivers such as the Thames, Severn or Trent.     

Gold ore-forming fluids of the Tanami region, Northern Australia

Fluid inclusion studies have been carried out on major gold deposits and prospects in the Tanami region to determine the compositions of the associated fluids and the processes responsible for gold mineralization. Pre-ore, milky quartz veins contain only two-phase aqueous inclusions with salinities ≤19 wt% NaCl eq. and homogenization temperatures that range from 110 to 410°C. In contrast, the ore-bearing veins typically contain low to moderate salinity (<14 wt% NaCl eq.), H₂O + CO₂ ± CH₄ ± N₂-bearing fluids. The CO₂-bearing inclusions coexist with two-phase aqueous inclusions that exhibit a wider range of salinities (≤21 wt% NaCl eq.). Post-ore quartz and carbonate veins contain mainly two-phase aqueous inclusions, with a last generation of aqueous inclusions being very CaCl₂-rich. Salinities range from 7 to 33 wt% NaCl eq. and homogenization temperatures vary from 62 to 312°C. Gold deposits in the Tanami region are hosted by carbonaceous or iron-rich sedimentary rocks and/or mafic rocks. They formed over a range of depths at temperatures from 200 to 430°C. The Groundrush deposit formed at the greatest temperatures and depths (260–430°C and ≤11 km), whereas deposits in the Tanami goldfield formed at the lowest temperatures (≥200°C) and at the shallowest depths (1.5–5.6 km). There is also evidence in the Tanami goldfield for late-stage isothermal mixing with higher salinity (≤21 wt% NaCl eq.) fluids at temperatures between 100 and 200°C. Other deposits (e.g., The Granites, Callie, and Coyote) formed at intermediate depths and at temperatures ranging from 240 to 360°C. All ore fluids contained CO₂ ± N₂ ± CH₄, with the more deeply formed deposits being enriched in CH₄ and higher level deposits being enriched in CO₂. Fluids from deposits hosted mainly by sedimentary rocks generally contained appreciable quantities of N₂. The one exception is the Tanami goldfield, where the quartz veins were dominated by aqueous inclusions with rare CO₂-bearing inclusions. Calculated δ ¹⁸O values for the ore fluids range from 3.8 to 8.5‰ and the corresponding δD values range from −89 to −37‰. Measured δ ¹³C values from CO₂ extracted from fluid inclusions ranged from −5.1 to −8.4‰. These data indicate a magmatic or mixed magmatic/metamorphic source for the ore fluids in the Tanami region. Interpretation of the fluid inclusion, alteration, and structural data suggests that mineralization may have occurred via a number of processes. Gold occurs in veins associated with brittle fracturing and other dilational structures, but in the larger deposits, there is also an association with iron-rich rocks or carbonaceous sediments, suggesting that both structural and chemical controls are important. The major mineralization process appears to be boiling/effervescence of a gas-rich fluid, which leads to partitioning of H₂S into the vapor phase resulting in gold precipitation. However, some deposits also show evidence of desulfidation by fluid–rock interaction and/or reduction of the ore-fluid by fluid mixing. These latter processes are generally more prevalent in the higher crustal-level deposits.     

Geographic and temporal trends in proboscidean and human radiocarbon histories during the late Pleistocene

The causes of large animal extinctions at the end of the Pleistocene remain a hotly debated topic focused primarily on the effects of human over hunting and climate change. Here we examine multiple, large radiocarbon data sets for humans and extinct proboscideans and explore how variation in their temporal and geographic distributions were related prior to proboscidean extinction. These data include 4532 archaeological determinations from Europe and Siberia and 1177 mammoth and mastodont determinations from Europe, Siberia, and North America. All span the period from 45,000 to 12,000 calendar years BP. We show that while the geographic ranges of dated human occupations and proboscidean remains overlap across the terminal Pleistocene of the Old World, the two groups remain largely segregated and increases in the frequency of human occupations do not coincide with declines in proboscidean remains. Prior to the Last Glacial Maximum (LGM; ca 21,000 years BP), archaeological ¹⁴C determinations increase slightly in frequency worldwide while the frequency of dated proboscidean remains varies depending on taxon and location. After the LGM, both sympatric and allopatric groups of humans and proboscideans increase sharply as climatic conditions ameliorate. Post-LGM radiocarbon frequencies among proboscideans peak at different times, also depending upon taxon and location. Woolly mammoths in Beringia reach a maximum and then decline beginning between 16,000 and 15,500 years BP, woolly mammoths in Europe and Siberia ca 14,500 and 13,500 BP, and Columbian mammoth and American mastodont only after 13,000 BP. Declines among woolly mammoths appear to coincide with the restructuring of biotic communities following the Pleistocene–Holocene transition.