江陵地区东周墓葬日用陶器年代序列

本通过大量已发表的资料,运用考古类型学方法,对学界中存在争议的江陵地区东周墓葬出土的日用陶器进行了年代排序。由于该地区东周墓葬中铜礼器和仿铜陶礼器的年代序列较为清楚且多取得共识,章选取铜礼器、仿铜陶礼器和日用陶器共存的墓葬为典型墓例和讨论的基础。作为一项基础性工作,本的研究成果将有助于楚化的深入探索。     

Emergence,collapse and continuity of the first political system in the Guadalquivir Basin from the fourth to the second millennium BC: The long-term sequence of Úbeda (Spain)

Over the last decade, a long-running archaeological project in the Guadalquivir Basin (Spain) has identified the emergence (c. 3000 BC) and collapse (between c. 2500 and c. 2300 BC) of a regional inter-settlement hierarchical system centred on the south-western Pyrite Belt and the Lower Guadalquivir Basin.     

ON THE RESOLUTION OF H/V MEASUREMENTS TO DETERMINE SEDIMENT THICKNESS,A CASE STUDY ACROSS A NORMAL FAULT IN THE LOWER RHINE EMBAYMENT,GERMANY

In recent years, H/V measurements have been increasingly used to map the thickness of sediment fill in sedimentary basins in the context of seismic hazard assessment. This parameter is believed to be an important proxy for the site effects in sedimentary basins (e.g. in the Los Angeles basin). Here we present the results of a test using this approach across an active normal fault in a structurally well known situation. Measurements on a 50 km long profile with 1 km station spacing clearly show a change in the frequency of the fundamental peak of H/V ratios with increasing thickness of the sediment layer in the eastern part of the Lower Rhine Embayment. Subsequently, a section of 10 km length across the Erft-Sprung system, a normal fault with ca. 750 m vertical offset, was measured with a station distance of 100 m. Frequencies of the first and second peaks and the first trough in the H/V spectra are used in a simple resonance model to estimate depths of the bedrock. While the frequency of the first peak shows a large scatter for sediment depths larger than ca. 500 m, the frequency of the first trough follows the changing thickness of the sediments across the fault. The lateral resolution is in the range of the station distance of 100 m. A power law for the depth dependence of the S-wave velocity derived from down hole measurements in an earlier study [Budny, 1984] and power laws inverted from dispersion analysis of micro array measurements [Scherbaum et aL, 2002] agree with the results from the H/V ratios of this study.     

Seashore Settlement Patterns in the Koné and Naïa Periods: Case Studies from Southwestern New Caledonia

As part of a geological survey in southwest mainland New Caledonia, potsherds were recorded in the profiles at four coastal sites. Subsequent archaeological investigations at two of these sites have allowed us to diversify the ceramic data and show them to be local variants of Podtanean, Puen, and Plum ceramic types. These are characteristic of production in the southern part of the archipelago during the first millennium BC and first millennium AD. The presence of fishing sites showing no indication of permanent settlements on these seashores, and the clear absence of second millennium AD occupations related to the “Traditional Kanak Cultural Complex”, characterized by large sedentary hamlets, illustrate a significant shift in settlement patterns between the first and second millennium AD.     

Potential of palaeofluid analysis for understanding oil charge history

Fluid inclusion data, particularly the distribution of hydrocarbon fluid inclusions and their chemistry, can provide insights into oil charge in a petroleum-prospective region. Examples from the UK Atlantic margin show how we can understand thermal regime, timing and chemistry of oil charge. Data from the UK Atlantic margin based on fluid inclusion temperature profiles shows anomalously high temperatures which are highest at the top of the Triassic–Eocene sequence. This is interpreted as a product of hot fluid flow, probably reflecting hydrothermal activity related to intrusion of sills at depth. The preservation of high temperatures also implies rapid migration from depth through fracture systems. Ar–Ar analysis of oil-bearing K-feldspar cements, and petrographic studies of oil inclusion distribution help delimit timing and migration pathways for the hot fluid charge and later fluid migration events. Coupled with compositional data for oils measured destructively (organic geochemistry) or non-destructively (fluorescence), these approaches allow the development of oil charge histories based on real data rather than theoretical modelling.     

Palaeolithic engravings and sedimentary environments in the Côa River Valley (Portugal): implications for the detection,interpretation and dating of open-air rock art

The pre-Magdalenian phase of the Côa River Valley open-air rock art is mostly distributed at the boundary between the rocky valley slopes and the floodplain that correspond to the most favourable geomorphological setting for the preservation of pecked and deeply superposed engravings of the most famous artistic phase of the area. The natural vertical panels of the engraved art located at this geomorphological interface have suffered weathering during two cold events of the Lateglacial. They were buried by several colluvial and alluvial deposits. The reconstruction of the sedimentary and archaeological context of the CôaRiver Valley engraving permits a better assessment of the preservation processes and interpretation of Palaeolithic open-air rock art.     

Ultrastructure and DNA sequence analysis of single Concentricystis cells from Alta Val Tiberina Holocene sediment

We successfully combined ultrastructure and chloroplast DNA analysis for single specimens of Concentricystis isolated from Holocene sediment by a palynology method based on filtration, progressive sieving and percoll-gradient sedimentation to concentrate fossil cells. We compared our method with the traditional harsh chemical treatment commonly used to isolate fossil pollen and spores. With our method, the cytoplasm of Concentricystis was sufficiently preserved to distinguish several cell structures by light and electron microscopy. DNA analysis of Concentricystis involved PCR amplification using specific primers for a spacer region of the chloroplast genome. Significant homologies were found with the Angiosperm chloroplast genome by BLAST DNA search for PCR product sequences.     

Effects of episodic fluid flow on hydrocarbon migration in the Newport‐Inglewood Fault Zone,Southern California

Fault permeability may vary through time due to tectonic deformations, transients in pore pressure and effective stress, and mineralization associated with water‐rock reactions. Time‐varying permeability will affect subsurface fluid migration rates and patterns of petroleum accumulation in densely faulted sedimentary basins such as those associated with the borderland basins of Southern California. This study explores the petroleum fluid dynamics of this migration. As a multiphase flow and petroleum migration case study on the role of faults, computational models for both episodic and continuous hydrocarbon migration are constructed to investigate large‐scale fluid flow and petroleum accumulation along a northern section of the Newport‐Inglewood fault zone in the Los Angeles basin, Southern California. The numerical code solves the governing equations for oil, water, and heat transport in heterogeneous and anisotropic geologic cross sections but neglects flow in the third dimension for practical applications. Our numerical results suggest that fault permeability and fluid pressure fluctuations are crucial factors for distributing hydrocarbon accumulations associated with fault zones, and they also play important roles in controlling the geologic timing for reservoir filling. Episodic flow appears to enhance hydrocarbon accumulation more strongly by enabling stepwise build‐up in oil saturation in adjacent sedimentary formations due to temporally high pore pressure and high permeability caused by periodic fault rupture. Under assumptions that fault permeability fluctuate within the range of 1–1000 millidarcys (10^?15–10^?12 m²) and fault pressures fluctuate within 10–80% of overpressure ratio, the estimated oil volume in the Inglewood oil field (approximately 450 million barrels oil equivalent) can be accumulated in about 24 000 years, assuming a seismically induced fluid flow event occurs every 2000 years. This episodic petroleum migration model could be more geologically important than a continuous‐flow model, when considering the observed patterns of hydrocarbons and seismically active tectonic setting of the Los Angeles basin.     

The stress regime of the Western Canadian Sedimentary Basin

All available information relevant to in situ stress orientations and magnitudes in the Western Canadian Sedimentary Basin (WCSB) were examined to provide a better understanding of how regional stress fields may affect geothermal development. The smallest principal stress is horizontal over most of the Western Canadian Sedimentary Basin, and it varies in magnitude across the region. Horizontal stress trajectories show that S_Hmax axes are generally aligned SW–NE. A total of 1643 measurements of microfracture and minifracture closure pressures, leak‐off pressures and fracture breakdown pressures have been harnessed to map S_Hmin gradients across the basin at depths of 156–500, 500–1000, 1000–4185 and 2000–4185 m. Vertical stress magnitudes, calculated in 91 wells, showed that at constant depth, S_V increases towards the Canadian Rocky Mountains. Resultant regional stress maps show consistent trends in orientation of stress axes. As a result, predictions can be made that propagation axes of subsurface hydraulic fractures will be dominantly SW–NE, except over the Peace River Arch area, where they will trend more towards SSW–NNE. Engineered geothermal systems in the WCSB can be optimised by drilling horizontal wells parallel to S_Hmin.     

Maintaining high fluid pressures in older sedimentary basins

High fluid pressures in old geologic basins, where the mechanisms that generate high fluid pressure have ceased to operate, pose the problem of how high fluid pressures are maintained through geologic time. Recent oil and gas exploration reveals that low permeability shales, the source beds for oil and gas, contain large quantities of gas that are now being exploited in many sedimentary basins in North America. No earlier analyses of how to maintain high fluid pressure in older sedimentary basins included a shale bed as a source of adsorbed gas; this is a new conceptual element that will fundamentally change the analysis. Such a large fluid source can compensate for a low rate of bleed off in a dynamic system. If the fluid source is large enough, as the gas within these shale source beds appears to be, there will no appreciable drop in pressure accompanying a low rate of leakage from the basin for long periods. For the dynamic school of basin analysts this may provide the missing piece in the puzzle, explaining how high fluid pressures are maintained for long periods of geologic time in a crust with finite, non-zero permeability. This is a hypothesis which needs to be tested by new basin analyses.