The Ancestral South Sandwich Arc (ASSA) has a short life-span of c.20 m.y. (Early Oligocene to Middle-Upper Miocene) before slab retreat and subsequent ‘resurrection’ as the active South Sandwich Island Arc (SSIA). The ASSA is, however, significant because it straddled the eastern margin of the Drake Passage Gateway where it formed a potential barrier to deep ocean water and mantle flow from the Pacific to Atlantic. The ASSA may be divided into three parts, from north to south: the Central Scotia Sea (CSS), the Discovery segment, and the Jane segment. Published age data coupled with new geochemical data (major elements, trace elements, Hf-Nd-Sr-Pb isotopes) from the three ASSA segments place constraints on models for the evolution of the arc and hence gateway development. The CSS segment has two known periods of activity. The older, Oligocene, period produced basic-acid, mostly calc-alkaline rocks, best explained in terms of subduction initiation volcanism of Andean-type (no slab rollback). The younger, Middle-Late Miocene period produced basic-acid, high-K calc-alkaline rocks (lavas and pyroclastic rocks with abundant volcanigenic sediments) which, despite being erupted on oceanic crust, have continental arc characteristics best explained in terms of a large, hot subduction flux most typical of a syn- or post-collision arc setting. Early-Middle Miocene volcanism in the Discovery and Jane arc segments is geochemically quite different, being typically tholeiitic and compositionally similar to many lavas from the active South Sandwich island arc front. There is indirect evidence for Western Pacific-type (slab rollback) subduction initiation in the southern part of the ASSA and for the back-arc basins (the Jane and Scan Basins) to have been active at the time of arc volcanism. Models for the death of the ASSA in the south following a series of ridge-trench collisions, are not positively supported by any geochemical evidence of hot subduction, but cessation of subduction by approach of progressively more buoyant oceanic lithosphere is consistent with both geochemistry and geodynamics. In terms of deep ocean water flow the early stages of spreading at the East Scotia Ridge (starting at 17-15 Ma) may have been important in breaking up the ASSA barrier while the subsequent establishment of a STEP (Subduction-Transform Edge Propagator) fault east of the South Georgia microcontinent (< 11 Ma) led to formation of the South Georgia Passage used by the Antarctic Circumpolar Current today. In terms of mantle flow, the subduction zone and arc root likely acted as a barrier to mantle flow in the CSS arc segment such that the ASSA itself became the Pacific-South Atlantic mantle domain boundary. This was not the case in the Discovery and Jane arc segments, however, because northwards flow of South Atlantic mantle behind the southern part of the ASSA gave an Atlantic provenance to the whole southern ASSA.
e-commerce usually refers to the commercial and trade activities, in the network environment, based on Browser / server applications, both buyers and sellers are not met for various business activities, realize consumers online shopping, merchants online transactions and online electronic payment and a variety of business / trade / finance activities such as a business operation mode.
e-commerce in the application of mobile Internet, mobile e-commerce. Mobile e-commerce is based on mobile communication network, mobile phones, personal digital assistants, handheld computers and other mobile intelligent terminals, e-commerce activities.
2012, e-commerce is both an opportunity and a challenge. The development of the Internet, the optimization of the environment, growth in the number of Internet users has brought great opportunities to the development of electronic commerce; however, it is this market with unlimited potential, attracted all walks of life to segmentation, which will undoubtedly bring fierce competition to the development of the industry.
related data show that as of June 2011, China’s Internet users reached 485 million, an increase of more than 27 million 700 thousand people by the end of 2010, Internet penetration rate rose to 36.2%, compared with 2010 increased by 1.9 percentage points. Meanwhile, the scale of China’s mobile phone users was 318 million, an increase of more than 14 million 940 thousand people by the end of 2010. Mobile phone users in the proportion of the total Internet users reached 65.5%, becoming an important part of China’s Internet users.
can see that the emergence of mobile e-commerce will be a challenge to traditional e-commerce. At the same time, the development of communication technology, the reduction of network tariff, the improvement of the hardware performance and the improvement of the application service provide a good precondition for mobile phone users to access the Internet through the mobile terminal.
huge mobile phone user groups, personalized business services, so that traditional e-commerce service providers to see the huge market potential of mobile e-commerce. Taobao, Dangdang and other companies have set up their own mobile e-commerce platform. It can be said that mobile e-commerce will be a new focus in the future of e-commerce enterprises.
operators, and how in this new field, while the development of mobile e-commerce West to a share? HC research next will from the operators in the field of mobile e-commerce development status and problems, on how to share the rapid development in the era of electronic commerce.
operators in the field of mobile e-commerce development in the following aspects:
1, the rapid development of mobile payment. Mobile payment anytime and anywhere and personalized service and a good platform for technology and other advantages, enough to meet the needs of people anywhere shopping, stocks, payment, travel and other business activities. Mobile payment can not only attract. The development of new users, expand the user base, broaden the scope of business, increase user stickiness, and can also improve the average customer spending, master the user’s mobile communications consumer other consumer behavior data, while