东南沿海地震带地震序列特征与迁移规律

研究了中国大陆东南沿海地震带地震的迁移规律和序列特征，以及与台湾地区Ｍｓ≥７．０级地震的关系。所得结果对该带的地震趋势估计有一定的参考意义。     

Holocene alluviation in Southeast England and some implications for palaeohydrological studies

Implicit in models of palaeohydrological reconstruction is the assumption that a close relationship exists between climate, hydrological regime, and fluvial systems. Unfortunately, there can be a number of complicating factors involved, some of which are becoming increasingly well known. Research into Holocene alluviation in southeast England has demonstrated some associated difficulties which range from the problem of relating anthropogenically modified drainage networks to an understanding of contemporary rates of floodplain development to the impact of prehistoric societies on valley sedimentation. A theoretical model is presented whereby varying geomorphic domains contributing to floodplain and valley fill construction can be recognized. It is suggested that attempts to apply this framework to palaeohydrological studies may assist in the realization of a more accurate reconstruction in which former hydrological responses are integrated within a broader palaeoenvironmental context.     

A conjugate strike-slip fault system within the extensional tectonics of Western Turkey

Three main shocks M-1, M-2 and M-3 (17 October 2005 at 05:45 UTC, M _w 5.4; 17 October at 09:46 UTC, M _w 5.8 and 20 October at 21:40 UTC, M _w 5.9) and their associated aftershocks within the Gulf of S i ğac i k, 50 km southwest of Izmir, Turkey were studied in detail. A temporary seismic network deployed during the activity allowed the hypocentre of M-3 and subsequent aftershocks to be determined with high accuracy. A relative relocation technique was used to improve the epicentres of M-1 and M-2. All three main shocks have strike-slip mechanisms which agree with the linear trends of the aftershock locations. Two distinct zones were illuminated by the aftershock locations. The zones contain clear echelon patterns with slightly different orientations from the trend of the aftershock distribution. M-2 and M-3 ruptured along of the eastern rupture zone which aligns N45°E. However the strike direction of M-1 is not clearly identified. The alignment of the two rupture zones intersect at their southern terminus at an angle of 90°. The fault zones form conjugate pair system and static triggering is considered as a probable mechanism for the sequential west to east occurrence of M-1, M-2 and M-3. This earthquake sequence provides seismological evidence for conjugate strike-slip faulting co-existing within a region dominated by north–south extension and well-developed east–west trending normal faults.     

中国东南沿海地震带大震重复性和大震减震作用

本文从物质分异的角度出发并利用现代小震活动资料,讨论了东南沿海地震带历史大震震源区及其附近,今后一段历史时期内是否有大震(M≥0)震源区大震重复性和大震减震作用问题。结果表明,这些历史震源区目前还处在减震阶段,今后一段时间只能以小震或中强地震的活动特点来显示这一弱化区。     

Long-term drainage evolution in the shoalhaven catchment,southeast highlands,Australia

The long-term evolution of streams in the Shoalhaven catchment of southeast New South Wales has been a contentious issue for decades. Several authors have suggested that the Shoalhaven River was captured at the sharp eastward bend near Tallong: this has been used as evidence for the westward migration of the east Australian divide in this area. Other workers, however, have argued that capture did not occur and that the location of the divide has been stable throughout the Tertiary. A vast sheet of sediments which spread across and infill a palaeovalley network cut into a broad undulating plain in the middle Shoalhaven catchment provides a record of stream behaviour since at least the start of the Tertiary. This record shows that the Shoalhaven River and many of its tributaries have maintained almost the same courses since at least the very Early Tertiary. This provides strong evidence against the capture hypothesis. The record further suggests that during the Paleogene these streams were graded to a level within the southeast Australian highlands; their depths of incision thus cannot be used as evidence for the extent of uplift of the southeast Australian highlands during this time.     

东南沿海地震区东部中强震活动特征

研究了1500年以来东南沿海地震区东部中强地震的活动特征。通过对其时序演变进程的分析,长乐-诏安地震带和邵武-河源地震带地震活动参数的对比,以及对第二活跃期中强地震迁移特点的研究,对该区今后的地震活动趋势作出了估计。     

Physico-chemical seasonal variability of a tropical estuary: major and minor elements in water and air

The lower reaches of the Coatzacoalcos River in southeast Mexico is an area of intense industrial development. The physico-chemical characteristics of the area have exhibited differences over the years. Apparently from the associated outcroppings of limestone in the Uxpanapa River Basin, the major elements that are dissolved show higher concentrations of Ca, Mg and HCO₃^– in the waters supplied by this river. The water in the Calzadas River contains high concentrations of Ca, SO₄ and HCO₃^– that are associated with the saline domes crossed by this river. Due to industrial discharges, the sulfate concentration is very high in the water and air during April. Nitrate concentration diminishes with salinity. Higher nitrate as well as nitrite and ammonia levels are present during flood season. Phosphate concentration, associated with high oxygen levels, is higher in January. Zn, Cu and Cr are higher during the dry season (April) when dilution is minimal and low levels of TOC are present. The smaller concentrations of Zn and Cu observed in January are associated with high TOC values in water. The lower levels of Cr present in August are associated with high amounts of suspended matter. Pajaritos Lagoon and Teapa-L, with large industrial discharges, have the highest nutrient and dissolved metal concentrations in the area. Air particles smaller than 2.5 m contain Fe, V, Ti, Cu, Zn, and high amounts of S. These anomalous concentrations of sulfates and metals are attributed to anthropogenic sources.     

Impact of El Nio on Large-scale Circulation of Southeast Asian Summer Monsoon

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滇东南芦柴冲大型银多金属矿床的海底喷流成矿作用沉积旋回划分

芦柴冲矿床位于滇东南砚山县境内,属南岭地区西南端－－滇东南早泥盆世的层控矿带。经野外调研和室内系统研究,发现矿床为典型非火山成因的、严格受沉积相（台盆相区）控制的海底喷流沉积成因矿床。矿床中发育的南北向同生扩张断裂是重要的控盆和控矿构造,是海底喷流成矿的含矿流体运移的通道,它具周期性的振荡运动的特点,导致海底喷流成矿具周期性的沉积旋回。     

Geochemical approach to magmatic evolution of Mt. Erciyes stratovolcano Central Anatolia, Turkey

Erciyes stratovolcano, culminating at 3917 m, is located in the Cappadocian region of central Anatolia. During its evolution, this Quaternary volcano produced pyroclastic deposits and lava flows. The great majority of these products are calc-alkaline in character and they constitute Kocdag and Erciyes sequences by repeated activities. Alkaline activity is mainly observed in the first stages of Kocdag and approximately first-middle stages of Erciyes sequences. Generally, Kocdag and Erciyes stages terminate by pyroclastic activities. The composition of lavas ranges from basalt to rhyolite (48.4–70.5 wt.% SiO₂). Calc-alkaline rocks are represented mostly by andesites and dacites. Some compositional differences between alkaline basaltic, basaltic and andesitic rocks were found; while the composition of dacites remain unchanged. All these volcanics are generally enriched in LIL and HFS elements relative to the orogenic values except Rb, Ba, Nb depleted alkaline basalt. ⁸⁷Sr/⁸⁶Sr and ¹⁴³Nd/¹⁴⁴Nd isotopic composition of the volcanics range between 0.703344–0.703964, 0.512920–0.512780 for alkaline basalts and change between 0.704322–0.705088, 0.512731–0.512630 for alkaline basaltic rocks whereas calc-alkaline rocks have relatively high Sr and Nd isotopic ratios (0.703434–0.705468, 0.512942–0.512600). Low Rb, Ba, Nb content with high Zr/Nb, low Ba/Nb, La/Yb ratio and low Sr isotopic composition suggest an depleted source component, while high Ba, Rb, Nb content with high La/Yb, Ba/Nb, low Zr/Nb and low ⁸⁷Sr/⁸⁶Sr ratios indicate an OIB-like mantle source for the generation of Erciyes alkaline magma. These elemental and ratio variations also indicate that the different mantle sources have undergone different degree of partial melting episodes. The depletion in Ba, Rb, Nb content may be explained by the removal of these elements from the source by slab-derived fluids which were released from pre-collisional subduction, modified the asthenospheric mantle. The chemically different mantle sources interacted with crustal materials to produce calc-alkaline magma. The Ba/Nb increase of calc-alkaline samples indicates the increasing input of crustal components to Erciyes volcanics. Sr and Nd isotopic compositions and elevated LIL and HFS element content imply that calc-alkaline magma may be derived from mixing of an OIB-like mantle melts with a subduction-modified asthenospheric mantle and involvement of crustal materials in intraplate environments.