Revised stratigraphy of the Blanchetown Clay, Murray Basin: age constraints on the evolution of paleo Lake Bungunnia

Paleo Lake Bungunnia covered more than 40 000 km2 of southern Australia during the Plio-Pleistocene, although the age and origin of the lake remain controversial. The Blanchetown Clay is the main depositional unit and outcrop at Nampoo Station in far-western New South Wales provides the most continuous lacustrine section preserved in the basin. Here the Blanchetown Clay represents the maximum lake fill and comprises: (i) a basal well-sorted sand with interbedded clay (Chowilla Sand), representing initial flooding at the time of lake formation; (ii) a thick sequence of green-grey clay comprised dominantly of kaolinite and illite, with the apparently cyclic occurrence of illite interpreted to represent cool and dry glacial climatic intervals; and (iii) a 2.6 m-thick sequence of finely laminated silt and silty clay, here defined as the Nampoo Member of the Blanchetown Clay. New magnetostratigraphic data constrain the age of the oldest lake sediments to be younger than 2.581 Ma (Matuyama-Gauss boundary) and probably as young as 2.4 Ma. This age is significantly younger than the age of 3.2 Ma previously suggested for lake formation. The youngest Blanchetown Clay is older than 0.781 Ma (Brunhes-Matuyama boundary) and probably as old as 1.2 Ma. The Nampoo Station section provides a framework for the construction of a regional Plio-Pleistocene stratigraphy in the Murray Basin.

Late Paleozoic depositional history of the Tarim basin, northwest China: an integration of biostratigraphic and lithostratigraphic constraints

This study provides the first detailed lithostratigraphic and biostratigraphic constraints for improving stratigraphic resolution for hydrocarbon prospecting and exploration in the Tarim basin. A total of 49 stratigraphic units (38 formations and 11 members), ranging in age from the latest Devonian to Permian, are reviewed or redefined in terms of nomenclatures, lithology, age constraints, and lateral distributions based on the detailed field works or newly published data. Of these, the Piqiang Formation (new formation) is proposed to include the reefal carbonates of Asselian-Sakmarian age from the northern Tarim. The subsurface upper Paleozoic stratigraphic framework of the desert areas of the basin is also established for the first time. The high-resolution, basinwide stratigraphic correlations reveal that the sedimentation of the basin in the late Paleozoic was extremely uneven. Of these, the Famennian to Changhsingian successions are completely recorded in the south-western margin areas of the basin. Here, five eustatic sedimentary cycles are well recognizable, suggesting the sedimentation was more eustatically controlled and little affected by local tectonism. The late Paleozoic successions of both Kalpin and Taklimakan regions are commonly interrupted by major hiatuses at various horizons, suggesting that the sedimentation was apparently modified by local tectonism. Of these, the northward movement of the Tarim block and its subsequent collision with the Yili microcontinent (part of the Kazakhstan plate) may be principally accountable for the discrepancy in the sedimentation of the various regions in the basin in the late Paleozoic.

A late Changhsingian (latest Permian) deep-water brachiopod fauna from Guizhou, South China

A deep-water brachiopod fauna (20 species in 19 genera) is described from the Late Permian Shaiwa Group of Ziyun, Guizhou, South China. New species include Pygmochonetes? shaiwaensis and Martinia ziyunensis. This fauna is associated with deep-water assemblages of pelagic radiolarians, foraminifers, bivalves and ammonoids. The brachiopod faunal correlations and age constraints of the associated fossil groups suggest that the Shaiwa fauna is late Changhsingian (latest Permian) in age. The Shaiwa fauna superficially resembles the coeval deep-water assemblage from Guangxi, South China; both are characterized by a mixture of deep-water brachiopods and shallow-water elements.

Socio-demographic constraints to travel behavior

Purpose – This study aims to ascertain the effect of socio-demographic constraints on dimension of travel choice. This study also seeks to derive personal ecological explanations for variation in travel preference, travel intention and travel choice behavior of a wide range of destinations.

Design/methodology/approach – A large representative sample of 49,105 Australian respondents is utilized. Binary logistic regression is used to determine the impact of constraint variables.

Findings – Age, income and life stage have significant differential and interactive effects on travel behavior. Socio-demographic variables act in different ways to constrain/free different types of travel behavior. However there are significant levels of travel by even the most constrained groups as well as significant amounts of non-travel by the least constrained sectors of our society. These impacts are country specific.

Research limitations/implications – The travel motivations of constraint groups need to be considered to order better understand travel behavior. Investigation of psychological and ecological facilitators and constraints to travel is needed.

Practical implications – This information is most useful for market segmentation and the development of constraint group destination marketing plans. Managers can use utilize such results to minimize the barriers to travel by particular groups.

Originality/value – This paper utilizes a large database to provide insights into the personal ecological constraints to travel.

Understanding travel behavior using demographic and socioeconomic variables as travel constraints

Samdahl and Jekubovich (1997) view constraints as a subset of reasons for not engaging in a particular behavior. There is limited empirical research on the role of demographic and socioeconomic variables as travel constraints. This study investigates the relationships between a wide range of short and long trip planning and travel behaviors and sociodemographic constraints comprised of age, income and life cycle.

This research uses data generated from a cross-sectional, self-completed survey on travel and tourism which was collected during 2003 and 2004 from 49,105 Australian respondents. This paper utilizes binomial regression to find that age, income and life stage have significant differential and interactive effects on travel behavior. The results show that sociodemographic variables act in different ways to constrain/free different types of travel behavior. Implications are provided for national and state based tourism authorities. There is a need to understand these phenomena. Current research is addressing these issues.

Constraints to park visitation: a meta-analysis of North American studies

The constraints that curb visitation to parks have received considerable research attention and remain an important issue. Constraints to outdoor leisure in parks include structural barriers, such as cost of entry, interpersonal barriers, for example, lack of a partner to visit with, or intrapersonal barriers, including lack of interest. Using a meta-analysis approach, this article integrates the findings of 22 North American studies with 541 estimates, conducted over a 30-year period, to determine the key constraints to park visitation based on various socio-demographic factors. The findings highlight the varying roles that constraints play in limiting the visitation of people according to race, age, gender, education and income. Gaps in the literature are identified, with implications for encouraging visitation for more constrained groups discussed. An agenda for future research is presented.