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Land-use change is emerging as one of the most critical environmental issues. As one of the most economically developed coastal regions in China, Zhejiang province has undergone substantial changes in land use over the last 2 decades. With rapid urban expansion and modernisation, sustainable land use on limited land resources has become a critical issue for local environment and socioeconomic development. The objectives of this study were to quantify land use/cover (LULC) changes and to attempt to identify socioeconomic drivers. Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper Plus (ETM+) images taken in 1985, 1993 and 2001 were used to map land use/cover changes. A stratified unsupervised classification technique was implemented in conjunction with visual interpretation. Using a modified Anderson's l/ll/lll-level classification scheme, an overall classification accuracy of 90% in level I was achieved. A LULC conversion matrix was produced for 2 decades to explore and explain LULC changes, All kinds of land uses have undergone varying degrees of change, among which are a notable loss of cropland and urban growth is the outstanding land-use change type. Urban sprawl is the main reason for the decrease in cropland. Spatially, the cropland loss has been uneven in different parts of the costal region in Zhejiang province. Temporally, land-use development has not stabilised and the two study periods, 1985-93 and 1993-2001, have different transition styles. [ABSTRACT FROM AUTHOR]

The Mesozoic geology of SE China has been widely considered to relate to subduction of the Paleo-Pacific Plate beneath the Eurasia, accompanied with extensive felsic magmatism. However, the relationship between the origin of the voluminous crust-derived magmatism and the Paleo-Pacific slab subduction remains unclear. Here we present petrology, zircon U-Pb-Hf isotope data, and whole-rock geochemical and isotopic compositions of two episodes of Cretaceous silicic volcanic rocks (~114–113 Ma for Group 1 and ~ 100–93 Ma for Group 2) from southeastern Zhejiang Province in SE China, to provide new constraints on the geodynamic transition of the Paleo-Pacific slab subduction. Both volcanic groups show similarly unradiogenic whole-rock ε Nd (t) and zircon ε Hf (t) values (ε Nd (t) = −8.6 to −6.4 and ε Hf (t) = −8.5 to −0.7 for Group 1, and ε Nd (t) = −7.1 to −6.1 and ε Hf (t) = −7.8 to −2.2 for Group 2). The limited emplacement of coeval mafic magmas and absence of mafic microgranular enclave and intermediate lavas suggest an insignificant role of mantle-derived melt either as a parental magma for differentiation or a mafic component during magma mixing. Instead, the low MgO and high concentrations of SiO 2 and incompatible elements and the evolved Nd and Hf isotopic compositions indicate derivation of these two groups of silicic magmas from similar hybrid crustal sources containing the metasedimentary rocks of Cathaysia basement and the newly accreted arc crust. Group 1 rocks contain a higher proportion of hydrous minerals (e.g., biotite) and Sr/Y and La/Yb CN ratios but lower zircon saturation temperature than Group 2. Such variations in mineral and geochemical compositions could be mainly attributed to the change of melting conditions from a relatively deeper, colder and water-fluxed crust to a shallower, hotter and less hydrous state. By combining our new results and previous studies of the late Mesozoic volcanic rocks in SE China, we propose that a geodynamic transition from subduction to slab rollback of the Paleo-Pacific Plate was responsible for such P-T-H 2 O variations of the crustal source. • 1. Two episodes of Cretaceous felsic volcanic rocks were identified in SE China. • 2. Both of them were formed by crustal melting at different P-T-H 2 O conditions. • 3. Transition from subduction to slab rollback occurred during ca. 110–90 Ma. [ABSTRACT FROM AUTHOR]

• The Liucheng OIB-type dolerite sill in the coastal region of SE China was formed during early Cretaceous. • Crustal components from both the sediments and mafic oceanic crust have been identified in the mantle source. • Rollback and tearing of the subducting slab may contribute to OIB-type magmatism at an active continental margin. Both early Cretaceous ocean island basalt (OIB)-type and subduction-related arc-type mafic magmatism occurred in coastal region of SE China. However, whether there existed a genetic relationship between the OIB-type magmatism and contemporary subduction of the Paleo-Pacific Ocean remains unclear. Here we present a comprehensive geochemical dataset of the Liucheng dolerite sill (~108 Ma) from coastal SE China, with aims to investigate the possible genetic link between them. The dolerite displays OIB-like trace element features and contains moderately radiogenic Sr-Nd-Pb-Hf and light Ca isotopic compositions. The nearly identical Sr-Pb isotopes between plagioclase and bulk rock indicate a minor role of crustal assimilation during magmatic evolution. The remarkable positive Ba anomalies, similar Sr and Pb isotopic compositions to the contemporary arc-type mafic rocks and light Ca isotopes suggest a source modified by recycled sediments. Additionally, the low La/Nb and Zr/Nb ratios indicate the involvement of an oceanic crust component that experienced dehydration and metamorphism to retain rutile. Further element-isotopic modeling suggests derivation of the parental magma from the asthenospheric mantle source that had been metasomatized by melts from both sediments and mafic oceanic crust. Considering that SE China was mainly influenced by subduction of the Paleo-Pacific Ocean during late Mesozoic, the subducting Paleo-Pacific slab was therefore the most likely candidate for such recycled components. Interaction of the melts from the recycled oceanic slab with the asthenospheric mantle, possibly as a consequence of rollback and tearing of the subducting Paleo-Pacific slab, formed the OIB-type source of the Liucheng dolerite sill. [ABSTRACT FROM AUTHOR]