The paleomagnetism and magnetic polarity stratigraphy of the mammal-bearing section of Anza Borrego State Park, California

We sampled 150 sites in fine-grained Plio-Pleistocene sediments of the Palm Springs and Imperial Formations. Sampling was confined to 3000 m of stratigraphically continuous section containing abundant vertebrate fossil remains of the Vallecito Creek, Arroyo Seco, and Layer Cake local faunas of the Irvingtonian and Blancan Land Mammal Ages. The magnetic stability of these sediments was sufficient to delineate the magnetic stratigraphy, which ranges from below the Cochiti event at the base, to the Matuyama reversed magnetic epoch at the top of the section. Eight faunal events are placed relative to the magnetic polarity sequence. They are cf. Pliohippus extinction, Geomys appearance, cf. Equus appearance, Tremarctos appearance, Hypolagus extinction, cf. Odocoileus appearance, Smilodon and ? Euceratherium appearance. The latter two faunal events characterize Irvingtonian Land Mammal Age. The transition from the Blancan to Irvingtonian Land Mammal Age occurs in the lower Matuyama magnetic epoch close to the Pliocene-Pleistocene boundary. The appearance of European migrants during the lower Matuyama magnetic epoch indicates that the Bering land bridge was exposed for animal migration between Europe and North America at this time.     

Origin of the Willaumez-Manus Rise,Papua New Guinea

The aseismic Willaumez-Manus Rise on the Bismarck Sea floor separates the Manus Basin from the New Guinea Basin. The rise does not appear to be an extinct spreading axis, or a remnant arc, but may be the result of excess magmatism possibly related to an inferred mantle hot spot beneath St. Andrew Strait. A preferred interpretation is that the rise is the raised edge of the New Guinea Basin, formed in response to a thermal anomaly beneath the extensional Manus Basin which formed later than the New Guinea Basin.     

Late-glacial and postglacial sedimentation in Lake Superior based on seismic-reflection profiles

Seismic reflection profiles (3.5 kHz) were obtained along more than 3500 km of shiptrack in Lake Superior within the last 2 yr. The acoustic character of profiles is categorized as: (I) a single, strong reflector at the lake floor, (II) a thick, acoustically transparent layer overlying a strong reflector, and (III) relatively thick sediment with internal acoustic reflectors. These profiles, in conjunction with sediment cores from the area, reveal that varved glacial-lacustrine sediment settled out preferentially in a trough between Isle Royale and the north shore, and to a lesser extent in other topographic depressions; bottom currents generated by storm waves prevent clay accumulation on till or bedrock in the open lake wherever the bottom is shallower than 100 m; bottom currents prevent deposition or erode bottom sediment in certain deep-water (> 200 m) valleys; and lacustrine sediment is disturbed by creep or slumping off Grand Portage, Minnesota, and by other processes such as dewatering in many other areas. These factors complicate sedimentation in Lake Superior, and must be considered when investigating any aspect of the lake sediment.     

Neighborhood covenants and restrictions: an examination of fit

Covenants and restrictions (C&Rs) have increased in popularity in recent decades, being commonly applied in new residential developments. Despite the fact that developers are more commonly writing C&Rs for their developments, little research has investigated how well C&Rs actually fit the preferences of residents. Recognizing this gap in the literature, this paper examines the fit of neighborhood C&Rs with resident preferences in Porter County, Indiana, a growing suburban/exurban place in the Chicago Metropolitan Statistical Area. The researcher conducted in-depth interviews with 51 residents to ascertain how well C&Rs fit resident preferences. The majority of interviewees stated that C&Rs match resident preferences because they believed that C&Rs promoted subdivision tidiness and worked to support property values. The minority view was that C&Rs do not fit because they are too strict and residents do not obey C&Rs. Interviewees who perceived a fit were more likely to have a lower level of engagement with C&Rs and were more likely to live in developments with no C&R enforcement attempts by the homeowners’ association (HOA). The results suggest the particular content of C&Rs does not seem to fit resident preference; rather the fact that C&Rs are not enforced fits resident preference. Seemingly, residents are content being unaware of the C&Rs, then they do not know if someone is breaking the rules or not. This may imply that residents would not want to have C&Rs in the first place.     

Financing rapid community reconstruction after catastrophic disaster: lessons from the 2008 Wenchuan earthquake in China

Catastrophic disasters can change the course of urban development and challenge the long-run sustainability of cities and regions. How to rapidly reconstruct communities impaired by catastrophic disaster is a world-wide challenge. The reconstruction after the 2008 Wenchuan earthquake in China was an unusual case of very rapid reconstruction after a catastrophic disaster. Over US$147 billion was invested to rebuild the damaged areas within 3 years. The reconstruction was not simply building back what was destroyed, but was used as an opportunity to advance national goals for urbanization, rural transformation, and poverty reduction. In this article, we review how the reconstruction was planned, budgeted, and financed in the sociopolitical context of 2008 China. Particularly, we discuss two innovative programs, namely pair assistance and land-based financing. Despite the unique circumstances of China, lessons can be learned to speed up post-disaster reconstruction and urban development in other countries. Conversely, this case illustrates that a narrow focus on physical reconstruction may overlook broader economic and social issues.

     

Euro-politics of scale: competing visions of the region in eastern Germany

As John Agnew (Political geography: a reader, 1997) has argued, political and economic change often occasions competing visions of the scales that are appropriate for organizing particular political and economic activities. Nowhere is this more evident than in the European Union, and eastern Germany offers compelling evidence of the contested nature of contemporary scalar politics. Yet a recent debate in human geography (see, e.g. Marston et al., Transactions of the Institute of British Geographers 30:416–432, 2005) calls into question the very concept of scale and rejects its hierarchical conceptualization. In light of this debate, it is appropriate to draw on real-world case studies to examine the ways in which geography figures into policy. Drawing on field work in Saxony, evidence is offered in the form of competing visions of regionalism in the EU context. The evidence presented complicates both hierarchical and flat notions of scale. The current process of querying space to identify those scales that are best-suited for the globalized economy offers insights into both the socially constructed nature of scale as well as the ways in which scalar lenses help to illuminate the geographical aspects (and consequences) of strategies for coping with structural changes.     

Hydraulic characteristics of the Maastrichtian sedimentary rocks of the southeastern Bida Basin, central Nigeria

A set of outcrop samples from the Lokoja and Patti Formations of the southern Bida Basin (Nigeria) was examined for grain size distribution, sedimentary and hydraulic characteristics. Most of the samples are well-sorted with an uniformity coefficient (U) ranging between 1.3 and 6.3. The mean effective grain diameter (d₁₀) is in the order of 0.11 mm, the mean value of d₉₀ was determined as 0.66 mm (both geometric mean) and the median grain size (d₅₀) as 0.23 mm. Based on these values, the sedimentary sequence can be described as ‘fine to medium sized sand’, having minor amounts of either silt, or coarse sand and some gravel. The total porosity of the samples was determined by laboratory methods to be in the range of 9–29%. The hydraulic conductivity (K) was determined according to Hazen.and Beyer, and by Shepherd's formula, the last resulting in a geometric mean of 3.3 m d⁻¹ or 3.3 darcy. The results are used to estimate local groundwater potential. The entire pore space (potential groundwater reservoir) for the area under study is estimated to be in the order of 290–430 km³. Because of higher hydraulic conductivities, it is recommended that the Lokoja Formation is concentrated on as a target for groundwater exploration.     

贵州遵义牛蹄塘组黑色岩系的硒同位素变化及其环境指示初探

西南早寒武世牛蹄塘组是分布在中国南方扬子地台的一套黑色岩系,区域上发育有典型富集多金属元素的硫化物矿化层.选取遵义松林小竹牛蹄塘组下部富硒、钼、镍等元素的黑色岩系剖面,利用Se同位素初步探讨了该剖面岩石的沉积环境和硒的可能来源.结果表明,小竹牛蹄塘组下部剖面黑色岩系的δ82/76SeSRM3149比值变化较大,下部底层含碳斑脱岩与磷块岩的变化范围在-4.35‰～ 4.11‰之间;中间镍钼层及碳质页岩、碳质碳酸盐岩的δ82/76SeSRM3149变化范围窄,平均值为0.9‰±0.23‰(n=4);上层碳质页岩为-1.24‰.结合已发表的钼同位素数据,认为中间岩石沉积于缺氧/无氧环境,但存在盆地海水与热液或充氧水团的混合;下层的岩石曾一度位于充氧与贫氧环境的边界面,局部岩石曾暴露地表经历了较强的风化和蚀变作用,海水中硒有可能来自底部富硒斑脱岩的氧化淋滤或海底热液.据此推测遵义松林小竹牛蹄塘组下部岩石的沉积环境极可能处在局限盆地靠近陆地的边缘部分,经历了充氧→贫氧→缺氧/无氧→贫氧的演化阶段.     

Isotopic and trace-element profiles across the New Britain island arc,Papua New Guinea

New Pb-, Sr-, and Nd-isotopic data have been obtained for the rocks of volcanoes overlying a wide range of depths (100–580 km) to the Wadati-Benioff Zone (WBZ) in the New Britain island arc, Papua New Guinea. Well-defined trends consistent with two-component mixing are observed in combined Pb-isotope/trace-element plots. One of the components is believed to represent a slab contribution whose isotopic signature, unlike those noted for several other arcs, appears to be dominated by subducted, altered, oceanic crust rather than by sediment. This conclusion is consistent with the results of a recent Be–B study of New Britain rocks. The influence of the slab component is considered to decrease as depth to the WBZ increases. Higher abundances of high-field-strength elements correlate with increasing depths to the WBZ, and may be indicative of smaller degrees of partial melting of the mantle wedge as WBZ depths increase. Abundances of other incompatible elements appear to reflect a complex interplay between the slab-derived flux and melting process.