Diverse protolith ages for the Mindoro and Romblon Metamorphics (Philippines): Evidence from single zircon U–Pb dating          下载免费PDF全文

Ulrich Knittel  Monika Walia  Shigeyuki Suzuki  Carla B. Dimalanta  Graciano P. Yumul Jr. 《Island Arc》2017,26(1)

Within the north‐eastern part of the Palawan Continental Terrane, which forms the south‐western part of the Philippine archipelago, several metamorphic complexes are exposed that are considered to be rifted parts of the Asian margin in South‐East China. The protolith age(s) and correlations of these complexes are contentious. The largest metamorphic complex of the Palawan Continental Terrane comprises the Mindoro Metamorphics. The north‐eastern part of this metamorphic complex has recently been found to be composed of protoliths of Late Carboniferous to Late Permian protolith age. However, meta‐sediments exposed at the westernmost tip and close to the southern boundary of the exposure of the Mindoro Metamorphics contain detrital zircons and with U–Pb ages, determined by LA–ICP–MS, in the range 22–56 Ma. In addition, zircons as young as 112 Ma were found in a sample of the Romblon Metamorphics in Tablas. As the youngest detrital zircons provide an upper age limit for the time of deposition in meta‐sediments, these results suggest that the Mindoro and Romblon Metamorphics comprise protoliths of variable age: Late Carboniferous to Late Permian in NE Mindoro; Eocene or later in NW Mindoro; Miocene at the southern margin of the Mindoro metamorphics; and Cretaceous or later on Tablas. The presence of non‐metamorphic sediments of Late Eocene to Early Oligocene age in Mindoro (Lasala Formation), which are older than the youngest metasediments, suggests that metamorphism of the young meta‐sediments of Mindoro is the result of the collision of the Palawan Continental terrane with the Philippine Mobile Belt in Late Miocene. Similarities of the age spectra of zircons from the Eocene to Miocene metamorphics with the Eocene to Early Miocene Lasala Formation suggest that the protoliths of the young metamorphics may be equivalents of the Lasala Formation or were recycled from the Lasala Formation.  相似文献   

The first post‐injection seismic monitor survey at the Ketzin pilot CO2 storage site: results from time‐lapse analysis          下载免费PDF全文

Fei Huang  Peter Bergmann  Christopher Juhlin  Monika Ivandic  Stefan Lüth  Alexandra Ivanova  Thomas Kempka  Jan Henninges  Daniel Sopher  Fengjiao Zhang 《Geophysical Prospecting》2018,66(1):62-84

The injection of CO₂ at the Ketzin pilot CO₂ storage site started in June 2008 and ended in August 2013. During the 62 months of injection, a total amount of about 67 kt of CO₂ was injected into a saline aquifer. A third repeat three‐dimensional seismic survey, serving as the first post‐injection survey, was acquired in 2015, aiming to investigate the recent movement of the injected CO₂. Consistent with the previous two time‐lapse surveys, a predominantly west–northwest migration of the gaseous CO₂ plume in the up‐dip direction within the reservoir is inferred in this first post‐injection survey. No systematic anomalies are detected through the reservoir overburden. The extent of the CO₂ plume west of the injection site is almost identical to that found in the 2012 second repeat survey (after injection of 61 kt); however, there is a significant decrease in its size east of the injection site. Assessment of the CO₂ plume distribution suggests that the decrease in the size of the anomaly may be due to multiple factors, such as limited vertical resolution, CO₂ dissolution, and CO₂ migration into thin layers, in addition to the effects of ambient noise. Four‐dimensional seismic modelling based on dynamic flow simulations indicates that a dynamic balance between the newly injected CO₂ after the second repeat survey and the CO₂ migrating into thin layers and being dissolved was reached by the time of the first post‐injection survey. In view of the significant uncertainties in CO₂ mass estimation, both patchy and non‐patchy saturation models for the Ketzin site were taken into consideration.  相似文献   

Grappling with Growth: Perceptions of Development and Preservation in Faster- and Slower-Growing Amenity Communities*     

Minkyung Park  Monika Derrien  Emilian Geczi 《社会与自然资源》2019,32(1):73-92

Amenity-rich rural communities attract tourists, retirees, second-home owners, and others whose values are often assumed to conflict with those of longtime residents. While prior research has examined attitudinal differences across types of residents, questions about the effects of community growth on residents’ attitudes remain unanswered. This study examines whether and how seasonal and permanent residents differ within and across towns experiencing different rates of growth, and the implications of differences for attitudes toward community development and preservation. Results showed that permanent residents (both short- and long-term) perceived community development initiatives as more important to maintaining future quality of life than did seasonal homeowners. Further, community growth rates had statistically significant effects: residents of slower-growth towns attributed higher importance to both development and preservation initiatives than did residents of faster-growing towns. Growth rate was thus a stronger predictor of attitudes toward both development and preservation than resident type.  相似文献