• Economic and Environmental Geology
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• v.45 no.3
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• pp.317-333
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• 2012

The Yeongweol Group is a Lower Paleozoic mixed carbonate-siliciclastic sequence in the Taebaeksan Basin of Korea, and consists of five lithologic formations: Sambangsan, Machari, Wagok, Mungok, and Yeongheung in ascending order. Sequence stratigraphic interpretation of the group indicates that initial flooding in the Yeongweol area of the Taebaeksan Basin resulted in basal siliciclastic-dominated sequences of the Sambangsan Formation during the Middle Cambrian. The accelerated sea-level rise in the late Middle to early Late Cambrian generated a mixed carbonate-siliciclastic slope or deep ramp sequence of shale, grainstone and breccia intercalations, representing the lower part of the Machari Formation. The continued rise of sea level in the Late Cambrian made substantial accommodation space and activated subtidal carbonate factory, forming carbonate-dominated subtidal platform sequence in the middle and upper parts of the Machari Formation. The overlying Wagok Formation might originally be a ramp carbonate sequence of subtidal ribbon carbonates and marls with conglomerates, deposited during the normal rise of relative sea level in the late Late Cambrian. The formation was affected by unstable dolomitization shortly after the deposition during the relative sea-level fall in the latest Cambrian or earliest Ordovician. Subsequently, it was extensively dolomitized under the deep burial diagenetic condition. During the Early Ordovician (Tremadocian), global transgression (viz. Sauk) was continued, and subtidal ramp deposition was sustained in the Yeongweol platform, forming the Mungok Formation. The formation is overlain by the peritidal carbonates of the Yeongheung Formation, and is stacked by cyclic sedimentation during the Early to Middle Ordovician (Arenigian to Caradocian). The lithologic change from subtidal ramp to peritidal facies is preserved at the uppermost part of the Mungok Formation. The transition between Sauk and Tippecanoe sequences is recognized within the middle part of the Yeongheung Formation as a minimum accommodation zone. The global eustatic fall in the earliest Middle Ordovician and the ensuing rise of relative sea level during the Darrwillian to Caradocian produced broadly-prograding peritidal carbonates of shallowing-upward cyclic successions within the Yeongheung Formation. The reconstructed relative sea-level curve of the Yeongweol platform is very similar to that of the Taebaek platform. This reveals that the Yeongweol platform experienced same tectonic movements with the Taebaek platform, and consequently that both platform sequences might be located in a body or somewhere separately in the margin of the North China platform. The significant differences in lithologic and stratigraphic successions imply that the Yeongweol platform was much far from the Taebaek platform and not associated with the Taebaek platform as a single depositional system. The Yeongweol platform was probably located in relatively open shallow marine environments, whereas the Taebaek platform was a part of the restricted embayments. During the late Paleozoic to early Mesozoic amalgamations of the Korean massifs, the Yeongweol platform was probably pushed against the Taebaek platform by the complex movement, forming fragmented platform sequences of the Taebaeksan Basin.

• Journal of Wetlands Research
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• v.22 no.1
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• pp.24-30
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• 2020

To assess the wetland systems' capability to reduce fine dust, we used an artificial wetland module of small-sized greenhouse (70cm W × 70cm L × 60cm H) which creates a closed system. Experiment was performed twice using four species in each experiment. Non-plantation, one species, or two species condition was created in each mesocosm. We measured air quality, primarily PM2.5 and PM10 at the initial open mesocosms and 1hr later since mesocosms were closed. The dry weight of vegetation was measured at the 2nd experiment. The decreased amount of PM2.5 and PM10 was 13.7±1.3 and 13.2±1.3 ㎍·m^-3hr^-1 in wetland condition and 15.0±1.4 and 13.8±1.5 ㎍·m^-3hr^-1 in dryland condition, respectively. In 2^nd experiment, the decreased amount of PM 2.5 and PM 10 in wetland condition was 13.7±1.3 and 9.2±1.5 ㎍·m^-3hr^-1, 15.0±1.4 and 8.8±1.4 ㎍·m^-3hr^-1 in dryland condition, respectively. Wetland showed higher removal effect due to its high productivity leading to more effective absorption of particulate matter. Furthermore, the aquatic characteristics of wetland system and high humidity helped purifying the air quality. This can be seen as another value of wetlands, which can be presented as one of the solutions to the problem of fine dust.