Revisiting Late Quaternary Slip-rate along the Maqu Segment of the Eastern Kunlun Fault, Northeast Tibet

The Late Quaternary slip rate along the Maqu segment of the eastern Kunlun Fault was estimated using a combination of high-resolution remote sensing imagery interpretation, field observations and differential Global Positioning System（GPS） measurements of offset river terraces, and 14 C dating of snail shells collected from offset risers. The results show that the left-slip rate along the segment is 3–5 mm/a, and that the vertical slip rate is 0.3–0.5 mm/a. Both the horizontal and vertical slips on the segment remain consistent over a distance of ~100 km. It means that no slip gradient as previously suggested occurred along the Maqu segment, and which thus might behave as an independent seismogenic fault. Judging from multiple relationships among young terrace offsets, we infer that co-seismic surface rupture produced by a characteristic earthquake with a magnitude of Ms7.0–7.5 on the Maqu fault could generate a horizontal slip of 4.5–5 m and a vertical slip of 0.45–0.5 m, with a corresponding ratio（Dh/Dv） of about 9. Two surface rupture events must have occurred over the past 3300 years, the latest one possibly between 1485 cal BP and 1730 cal BP.

Stratigraphy of late Quaternary deposits in the mid-western North Yellow Sea

The North Yellow Sea(NYS) is characterized by strong land-sea interaction and paleoenvironmental changes with sea-level fluctuations during the late Quaternary. However, large-time scale depositional stratigraphy in this area and its relationship with sea-level changes remain unresolved. Highresolution seismic profiles from NYS were subdivided into eleven seismic units(U1 to U11 in descending order). A 70.6-m-long borehole(DLC70-2) from localities on seismic profiles, analyzed for lithology, microfossil assemblages and geochronology, comprises eleven sedimentary units(D1 to D11 in descending order), which were clearly correlated with the eleven seismic units. These units constitute four distinctive sequences(SQ1 to SQ4 from top to bottom) bounded by three sequence boundaries(S3, S5 and S10) with obvious depositional hiatus, correlated with sea-level lowstands of MIS2, MIS4 and MIS6, respectively. The lowermost SQ4 below S10, has been identified only upper part of transgressive systems tract(TST)(D11, tidal flat facies in early MIS6). SQ3 overlying S10 consists of a set of lowstand systems tracts(LST)(D10, fluvial to incised-channel filling facies in late MIS6), TST and highstand systems tracts(HST)(D9 to D6, interactive deposits of neritic and littoral facies in MIS5 and early MIS4). SQ2 above S5 is composed of LST(D5, channel-filling facies in late MIS4) and TST(D4, littoral to estuary facies in early-middle MIS3), but lack of HST resulting from subaerial exposure and channel incising during the Last Glacial Maximum(LGM). The uppermost SQ1 overlying S3 comprises LST(D3, channel-filling to flooding plain or marsh facies in MIS2), Holocene TST(D2, littoral and tidal sand ridge facies) and HST(D1, neritic facies). The unusual depositional stratigraphy was largely dominated by sea-level fluctuations and the Bohai Strait topography. This study confirms that TSTs are relative continuous and widely distributed, while LSTs vary considerably in thickness and lateral extent since MIS6 in NYS.

A Late Quaternary Climate Record Based on Multi-Proxies Analysis from the Jiaochang Loess Section in the Eastern Tibetan Plateau,China

We compared the stable carbon isotopic records from a loess transect of the Jiaochang in the eastern Tibetan Plateau, spanning the last -21,000 years, with multiproxy data for pedogenesis, including magnetic susceptibility, clay fraction, Fed/Fet ratio, carbonate and total organic carbon content, in order to probe the mechanisms of δ^13C values of organic matter and Late Quaternary climate variations in the eastern Tibetan Plateau. Our results indicate that there is no simple relationship between δ^13C of organic matter and summer monsoon variations. The change in δ^13C values of organic matter （in accordance with the ratios of C3 to C4 plants） results from the interaction among temperature, aridity and atmospheric pCO2 level. Drier climate and lower atmospheric pCO2 level contribute to positive carbon isotopic excursion, while negative carbon isotopic excursion is the result of lower temperature and increased atmospheric pCO2 level. Additionally, our results imply that the Tibetan monsoon may play an important role in climate system in the eastern Tibet Plateau, which specifically reflects frequently changing climate in that area. The results provide new insights into the forcing mechanisms on both the δ^13C values of organic matter and the local climate system.

Characteristics and accumulation model of the late Quaternary shallow biogenic gas in the modern Changjiang delta area, eastern China

The Changjiang（Yangtze）is one of the largest rivers in the world.It formed a huge incised valley at its mouth during the Last Glacial Maximum;the incised-valley fill,approximately 80–110 m thick,supplies an important foundation for the generation of shallow biogenic-gas reservoirs.Two cores and 13 cone penetration tests were used to elaborate the characteristics,formation mechanism,and distribution of the shallow biogenic-gas reservoirs in the study area.The natural gas is mainly composed of CH4（generally[95%）with a δ^13CCH4 and δ^13CCO2 of-75.8 to-67.7% and -34.5 to-6.6%,respectively,and a δDCH4 of-215 to-185%,indicating a biogenic origin by the carbon dioxide reduction pathway.Commercial biogenic gas occurs primarily in the sand bodies of fluvial-channel,floodplain,and paleo-estuary facies with a burial depth of 50–80 m.Gas sources as well as cap beds are gray to yellowish-gray mud of floodplain,paleoestuary,and offshore shallow marine facies.The organic matter in gas sources is dominated by immature type Ⅲ kerogen（gas prone）.The difference in permeability（about4–6 orders of magnitude）between cap beds and reservoirs makes the cap beds effectively prevent the upward escape of gas in the reservoirs.This formation mechanism is consistent with that for the shallow biogenic gas in the late Quaternary Qiantang River incised valley to the south.Therefore,this study should provide further insight into understanding the formation and distribution of shallow biogenic gas in other similar postglacial incised-valley systems.

The sedimentation rates in the Okinawa Trough during the Late Quaternary

On the basis of accelerator mass spectrometer radiocarbon （AMS ^14C） dating, sedimentation rates of 11 cores collected from the northern to southern Okinawa Trough are discussed. The sedimentation rates in the Okinawa Trough roughly range from 11 to 39cm/ka, and the average is 23.0cm/ka. China＇s continental matter is the main sediment source of the middle Okinawa Trough and has important contribution to the northern and southern Okinawa Trough. The sedimentation rates during the marine oxygen isotope （MIS） 2 are uniformly higher than those during MIS 1 in the northern and middle Okinawa Trough while they are on the contrary in the southern Okinawa Trough. Sedimentation rates in the Okinawa Trough can be one of the proxies of sediment source and an indicator of cooling events.

Late Quaternary Activity of the Huashan Piedmont Fault and Associated Hazards in the Southeastern Weihe Graben,Central China

The Weihe Graben is not only an important Cenozoic fault basin in China but also a significant active seismic zone. The Huashan piedmont fault is an important active fault on the southeast side of the Weihe Graben and has been highly active since the Cenozoic. The well–known Great Huaxian County Earthquake of 1556 occurred on the Huashan piedmont fault. This earthquake, which claimed the lives of approximately 830000 people, is one of the few large earthquakes known to have occurred on a high–angle normal fault. The Huashan piedmont fault is a typical active normal fault that can be used to study tectonic activity and the associated hazards. In this study, the types and characteristics of late Quaternary deformation along this fault are discussed from geological investigations, historical research and comprehensive analysis. On the basis of its characteristics and activity, the fault can be divided into three sections, namely eastern, central and western. The eastern and western sections display normal slip. Intense deformation has occurred along the two sections during the Quaternary; however, no deformation has occurred during the Holocene. The central section has experienced significant high–angle normal fault activity during the Quaternary, including the Holocene. Holocene alluvial fans and loess cut by the fault have been identified at the mouths of many stream valleys of the Huashan Mountains along the central section of the Huashan piedmont fault zone. Of the three sections of the Huashan piedmont fault, the central section is the most active and was very active during the late Quaternary. The rate of normal dip–slip was 1.67–2.71±0.11 mm/a in the Holocene and 0.61±0.15 mm/a during the Mid–Late Pleistocene. As is typical of normal faults, the late Quaternary activity of the Huashan piedmont fault has produced a set of disasters, which include frequent earthquakes, collapses, landslides, mudslides and ground fissures. Ground fissures mainly occur on the hanging–wall of the Huashan piedmont fault, with landslides, collapses and mudslides occurring on the footwall.

Late Quaternary diatom and sea level changes in estuarine plain of the Jiulong River

Four units and twenty-four zones of diatom have been discerned in the Borehole ZK5 in the estuarine plain of the Jiulong River, Fujian Province. Comprehensive analysis of these, together with microbiological assemblages and age determinations in some other boreholes, shows that during the Late Wurm Glacial, sea level of the study area rose and fell frequently, but had principally been in the environments of estuary-bay. This mainly resulted from the tectonic subouction. In this period 3 low sea levels occurred. at 18, 16 and 12 kaBP respectively. During Holocene, sea weter intruded massively and the sea level over the transgnaion maximum had been 5-10 m higher than that of the present.

Late Quaternary Paleoclimatic Change in the Ulleung Basin,East Sea,Korea

Paleoclimatic changes in the late Quaternary sediments deposited in the East Sea were analyzed by studying diatoms. A total of 95 species belonging to 47 genera were identified from the Core02GHP-02 of the Ulleung Basin in the East Sea, Korea. In the Core 02GHP-02, U-Oki（169–181 cm; 9.3 ka）, AT（464–465.5 cm; 22 ka） and U–Ym（556–559 cm; 33 ka） tephra layers were recognized. The chronological divisions of 02GHP-02 may be correlated with the climatic changes from the glacial interval（730–620 cm; MIS3）, to interstadial（620–500 cm; MIS3）, to the last glacial maximum（500–390 cm; MIS 2）, to the deglaciation（390–290 cm; MIS 2）, to the late glacial（290–190 cm; MIS 1）, and to the Holocene（190–10 cm; MIS 1）. It is speculated that diatoms were rarely found during the glacial interval when the 02GHP-02 core was deposited; during the interstadial（MIS 3） and deglaciation, a mixture of warm-water and cold-water species were found. In particular, Fragilariopsis doliolus seems to have appeared in the East Sea after 8 ka BP. In the lower layers of the Holocene deposits, cold-water species such as Neodenticula seminae were frequently found, while in the upper layers, warm-water species such as Hemidiscus cuneiformis were found in relatively large abundance. Therefore, the findings indicate that the climate became warmer during the transition from the lower layer to the upper layer of the Holocene deposits.

Paleoenvironmental changes during the late Quaternary as inferred from foraminifera assemblages in the Laizhou Bay

Controlled by climate changes, there were three large-scale transgressions and regressions around the Bohai Sea during the late Quaternary, which were accepted by most geologists. However, a big controversy still exists about the time when the transgressions occurred separately. In order to find out the process of the paleoenvironmental changes around the Bohai Sea in the late Quaternary, the foraminifera assemblages from a new borehole Lz908 in the southern coast of the Laizhou Bay were studied, and then the transgressive strata were indentified. Combined with accelerator mass spectrometry radiocarbon 14C（AMS14C） and optically stimulated luminescence（OSL） ages, the occurrence time of these transgressions were re-determined. The result showed that three major large-scale transgressions occurred separately at the beginning of marine isotopic stage 7（MIS7）, the last interglacial period（MIS5） and the Holocene. In addition, a small-scale transgression occurred in the mid-MIS6, and the corresponding transgressive stratum was deposited. The transgressive deposition of MIS3 was also discovered in this study. However, the characteristics of the foraminifera indicated the environment during this period was colder than that in the MIS5. By comparison with the global sea-level changes, the paleoenvironmental changes around the Bohai Sea in the late Quaternary can be consistent with the global climate changes.

Paleoceanographic records in the Chukchi Basin, western Arctic Ocean during the late Quaternary

The late Quaternary paleoceanographic changes in the western Arctic Ocean are revealed by quan- titative studies of foraminiferal abundance, ice-rafted detritus （IRD） and its mineralogical and petrological compositions, planktonic Neogloboquadrina pachyderma （sin.） （Nps）-δ18O and -δ13C, biogenic and non-biogenic components in Core M03 token from the Chukchi Basin during the Sec- ond Chinese National Arctic Expedition cruise. Seven IRD events appeared at MIS 7, 5, 3 and 1. These IRD were carried in massive icebergs, which were exported to the Beaufort Sea through the M＇Clure Strait Ice Stream, Canadian Arctic Archipelago, and then transported into the Chukchi Basin by the Beaufort Gyre. Low IRD deposition occurred during the glacial times when more extended ice cover and weakened Beaufort Gyre, while the open water condition and the intensified Beaufort Gyre during interglacial periods favored the IRD deposition. Therefore, the IRD events not only indicate the provenance of coarser detritus and ice export events, but also reflect the evolutionary histories of the Beaufort Gyre and North American ice sheet. Seven light Nps-δ18O and -δ13C excursions could respond to enhanced rates of sea ice formation resulting in the pro- duction and sinking of isotopically light brines, but was irrelevant to the warm Atlantic water and freshwater inputs. Whereas, the heavy Nps-δ18O and -δ13C values separately reflect the lessened Arctic freshwater and Pacific water, and well-ventilated surface water from the continental shelf and halocline water. Variations of CaCO3 content and planktonic foraminiferal abundance during the interglacial and glacial periods can demonstrate the incremental or diminishing input of the Atlantic water, while the total organic carbon （TOC） and opal contents increased and decreased during the glacial and interglacial periods, respectively, which could be related to the TOC degradation, opal dissolution and redox conditions of interface between the bottom water and sediments.

The Late Quaternary Coastal Geo-Environment Evolution and Modern Process of Bohai Bay,China

Paleoenvironmental reconstruction is fundamental to understand the modern environmental changes and to predict future environment, which is especially critical to understand the evolution of land and sea during geological periods. However, the basic geological research on China＇s muddy coastal zone is not enough to provide quantitative data to compare with global changes. Therefore, in 2011, China Geological Survey deployed the ＂Late Quaternary geo-environmental evolution and modern process of China＂ project, and focused on the muddy coastal zones of the Liaodong Bay, Bohai Bay, the Yellow River Delta, Yangtze River Delta and Pearl River Delta （Fig. 1）. Next we will briefly introduce our latest results in the Bohai Bay.

Facies character and geochemical signature in the late Quaternary meteoric diagenetic carbonate succession at the Xisha Islands,South China Sea

The late Quaternary shallow-water carbonates have been altered by a variety of diagenetic processes,and further influenced by high-amplitude global and regional sea level changes.This study utilizes a new borehole drilled on the Yongxing Island,Xisha Islands to investigate meteoric diagenetic alteration in the late Quaternary shallowwater carbonates.Petrographic,mineralogical,stable isotopic and elemental data provide new insights into the meteoric diagenetic processes of the reef limestone.The results show the variation in the distribution of aragonite,high-Mg calcite(HMC)and low-Mg calcite(LMC)divides the shallow-water carbonates in Core SSZK1 into three intervals,which are UnitⅠ(31.20-55.92 m,LMC),UnitⅡ(18.39-31.20 m,aragonite and LMC)and UnitⅢ(upper 18.39 m of core,aragonite,LMC and HMC).Various degrees of meteoric diagenesis exist in the identified three units.The lowermost UnitⅠhas suffered almost complete freshwater diagenesis,whereas the overlying UnitsⅡandⅢhave undergone incompletely meteoric diagenesis.The amount of time that limestone has been in the freshwater diagenetic environment has the largest impact on the degree of meteoric diagenesis.Approximately four intact facies/water depth cycles are recognized.The cumulative depletion of elements such as strontium(Sr),sodium(Na)and sulphur(S)caused by duplicated meteoric diagenesis in the older reef sequences are distinguished from the younger reef sequences.This study provides a new record of meteoric diagenesis,which is well reflected by whole-rock mineralogy and geochemistry.

Characteristics of Late-Quaternary Activity and Seismic Risk of the Northeastern Section of the Longmenshan Fault Zone

Following the 2008 Wenchuan M8 earthquake,the seismic risk of the northeastern section of the Longmenshan fault zone and the adjacent Hanzhong basin has become an issue that receives much concern.It is facing,however,the problem of a lack of sufficient data because of little previous work in these regions.The northeastern section of the Longmenshan fault zone includes three major faults：the Qingchuan fault,Chaba-Lin＇ansi fault,and Liangshan south margin fault,with the Hanzhong basin at the northern end.This paper presents investigations of the geometry,motion nature,and activity ages of these three faults,and reveals that they are strike slip with normal faulting,with latest activity in the Late Pleistocene.It implies that this section of the Longmenshan fault zone has been in an extensional setting,probably associated with the influence of the Hanzhong basin.Through analysis of the tectonic relationship between the Longmenshan fault zone and the Hanzhong basin,this work verifies that the Qingchuan fault played an important role in the evolution of the Hanzhong basin,and further studies the evolution model of this basin.Finally,with consideration of the tectonic setting of the Longmenshan fault zone and the Hanzhong basin as well as seismicity of surrounding areas,this work suggests that this region has no tectonic conditions for great earthquakes and only potential strong events in the future.

The elemental geochemical characteristics of Late Quaternary rock core from Yanwo Lake in the Great Wall Station area， King George Island， Southwest Antarctica

This paper is manily to treat the change regularity of the contens,distributions, enrich coefficients and correlative coefficients of some trace and constant elements in the sediments of Late Quaternary rock core from Yanwo Lake in the Great Wall Station area, King George Island and to discuss the sedimentary sources in Yanwo Lake and the periodical changes of Late Quaternary climate and the environment in the area. It is concluded that the elastic sedimentary rocks, including volcanic sedimentary rocks, around Yanwo Lake are the major sources of Yanwo Lake sedimentsi the mantle material is also one of its sources and what is more, the continent-sourced materials are transported by the Antarctic glacier.

Late Quaternary Strata and Carbon Burial Records in the Yellow River Delta, China

Sediment carbon sequestration plays an essential role in mitigating atmospheric CO2 increases and the subsequently global greenhouse effect. To clarify the late Quaternary strata and carbon burial records in Yellow River delta(YRD), detailed analysis of benthic foraminifera, total carbon(TC), organic carbon(Corg), sedimentary characteristics and moisture contents of sediments, was performed on core ZK3, 30.3 m in length and obtained from YRD in 2007. Eight depositional units(designated U1-U8 in ascending order) were identified. A comprehensive analysis method of historical geography and sedimentary geology was used to determine the precise depositional ages of the modern Yellow River delta(MYRD), from which pre-MYRD ages were deduced. The results indicates that the maximum burial rates of TC, inorganic carbon(IC) and Corg occurred in the delta front(U5), and the minimum in the shallow sea(U3). Remarkable high sedimentation rates in the MYRD are responsible for burial efficiency of carbon, with an average rate of Corg burial reaching 2087±251 g(m2 yr)-1, and that of IC reaching 13741±808 g(m2 yr)-1, which are much higher than those of other regions with high contents of Corg. Therefore, YRD has a significant burial efficiency for carbon sequestration.

Was the enclosed Qaidam Basin of The Tibetan Plateau Accumulative or Erosive during the Late Quaternary?

A geological feature in the Qaidam Basin known as the"Shell Bar"contains millions of freshwater articulated clam shells buried in-situ.Since the 1980s this feature in the now hyper-arid basin has been interpreted to be lake deposits that provide evidence for a warmer and more humid climate than present during late Marine Isotope Stage 3(MIS 3)(Bowler et al.,1986).However,the global climate during

Planktonic Foraminiferal Assemblage Variations of Ontong-Java Plateau during Late Quaternary and Their Implications for Paleotemperature in the Western Pacific Warm Pool

Ocean Drilling Program (ODP) Site 807A was recovered from the Ontong-Java plateau, western equatorial Pacific. Quantitative analysis of planktonic foraminifera, combined with oxygen and carbon isotope data, reveals the glacial-interglacial variations of sea-surface temperature and the upper water vertical structure in this region during the late Quaternary. Our results indicate that since 530 ka sea-surface temperature (SST) and the depth of thermocline (DOT) have changed significantly in the western Pacific warm pool (WPWP). The average glacial-interglacial annual SST difference was up to 4.2 ℃, and the DOT fluctuations could exceed more than 100 m, further suggesting the instability of the WPWP. The spectral analyses of SST and DOT reveal two dominating cyclicities—the typical 100 ka cycle and the semi-precessional cycle, which is significant in the tropical spectrum, indicating that late Quaternary paleoceanographic changes in the study area were influenced not only by a high latitude forcing but also by tropic-driving factors.

Discussion of the Horizontal Intensity of Late Quaternary Fault Activity Along the Tianjingshan Fault Zone in Different Time Intervals and Fault Segments

By computing and classifying the data of gully offset obtained from field surveys along the Tianjingshan fault zone and estimating the ages of three types of gullies,the strike-slip rates along the fault zone are discussed in different time intervals and fault segments.The results suggest that the intensity of activity along the fault zone is not strong,but the differences between different time intervals and fault segments since the late Pleistocene have been obvious.The average rates range from 0.23 mm/a to 1.62 mm/a.The largest average rate is 1.40 mm/a,which occurred in the early and middle of late Pleistocene along the western segment of the fault zone.Since the late stage of the late Pleistocene,the center of faulting activity of the fault zone has shifted to the middle segment,and the average slip rates range have changed from 1.30 mm/a to 1.63 mm/a.

A New Species of Fossil <i>Mus</i>(Muridae, Mammalia) from the Late Quaternary Deposits of Narmada Valley, Central India

A new species of fossil Mus (Muridae, Rodentia) is described from the Pleistocene fluviatile deposits of the Narmada valley (Central India). The species, Mus narmadaensis sp. Nov., has a comparatively smaller lower molar which is characterized by a narrow molar with well connected cusps, small anterior expansion of lingual anteroconid, protoconid and metaconid, reduced posterior cingulum in addition to hypoconid and entoconid nearly at the same level. The large M3 has centrally placed bulbous hypoconid. Among the extant species, the present one is closest to M. shortridgei in having similarly placed protoconid and metaconid in M1 and a well developed hypoconid in M3.

Preliminary study on late Quaternary foraminiferal assemblage in the Bransfield Strait， West Antarctica and its significance of environment

species foraminifera including in 14 genera were encountered from 39samples of core PC10, which were drilled in the Bransfield Strait of Antarctic Peninsula. They are divided into 3 assemblages as follow: 1. Siliceous shell assemblage; 2.Calcareous shell assemblage; 3. Mixed shell assemblage. The Siliceous shell assemblageoccurred in normal deep-sea, with weaker water dynamic condition. The Calcareousshell assemblage was formed by turbidity now, while the Mixed shell assemblage represented intense to weaker water dynamic condition. It changed from warm to cold towarm during the late Quaternary.