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- Can, Yang, et al.
(författare)
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Amplitude Variation with Offset Responses Modeling Study of Walkaway Vertical Seismic Profile Data at CO(2) Geological Storage Site, Ketzin, Germany
- 2011
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Ingår i: Acta Geologica Sinica. - 1000-9515 .- 1755-6724. ; 85:5, s. 1118-1126
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Tidskriftsartikel (refereegranskat)abstract
- An important component of any CO(2) sequestration project is seismic monitoring for tracking changes in subsurface physical properties, such as velocity and density. Different reservoirs have different amplitude variation with offset (AVO) responses, which can define underground conditions. In the present paper we investigate walkaway vertical seismic profile (VSP) AVO response to CO(2) injection at the Ketzin site, the first European onshore CO(2) sequestration pilot study dealing with research on geological storage of CO(2). First, we performed rock physics analysis to evaluate the effect of injected CO(2) on seismic velocity using the Biot-Gassmann equation. On the basis of this model, the seismic response for different CO(2) injection saturation was studied using ray tracing modeling. We then created synthetic walkaway VSP data, which we then processed. In contrast, synthetic seismic traces were created from borehole data. Finally, we found that the amplitude of CO(2) injected sand layer with different gas saturations were increased with the offset when compared with the original brine target layer. This is the typical class III AVO anomaly for gas sand layer. The AVO responses matched the synthetic seismic traces very well. Therefore, walkaway VSP AVO response can monitor CO(2) distribution in the Ketzin area.
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- Dalsätt, Johan, et al.
(författare)
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A New Enantiornithes (Aves) from the Early Cretaceous of China
- 2014
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Ingår i: Acta Geologica Sinica. - : Wiley. - 1000-9515 .- 1755-6724. ; 88:4, s. 1034-1040
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Tidskriftsartikel (refereegranskat)abstract
- A new bird from the early Cretaceous Yixian Formation of Liaoning, China is described. This new species, Grabauornis lingyuanensis, shares several synapomorphies with the Enantiornithes. The specimen is relatively well preserved. The skeletal morphology of Grabauornis bears close resemblance to that of other Chinese members of this clade. The brachial index (the ratio between the lengths of humerus and ulna) is 0.95, which is close to the average for enantiornithine birds. It indicates that Grabauornis was a rather good flyer, and the presence of an alula in the wing further testifies to this.
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- Sha, Jingeng, et al.
(författare)
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Stratigraphy of the Triassic-Jurassic Boundary Successions of the Southern Margin of the Junggar Basin, Northwestern China
- 2011
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Ingår i: Acta Geologica Sinica. - : Wiley. - 1000-9515. ; 85:2, s. 421-436
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Tidskriftsartikel (refereegranskat)abstract
- The Triassic-Jurassic (Tr-J) boundary marks a major extinction event, which (similar to 200 Ma) resulted in global extinctions of fauna and flora both in the marine and terrestrial realms. There prevail great challenges in determining the exact location of the terrestrial Tr-J boundary, because of endemism of. : and the scarcity of fossils in terrestrial settings leading to difficulties in linking marine and terrestrial sedimentary successions. Investigation based on palynology and bivalves has been carried out over a 1113 m thick section, which is subdivided into 132 beds, along the Haojiagou valley on the southern margin of the Junggar Basin of the northern Xinjiang, northwestern China. The terrestrial Lower Jurassic is conformably resting on the Upper Triassic strata. The Upper Triassic covers the Huangshanjie Formation overlaid by the Haojiagou Formation, while the Lower Jurassic comprises the Badaowan Formation followed by the Sangonghe Formation. Fifty six pollen and spore and one algal on were identified from the sediments. Based on the key-species and abundance of spores and pollen, three zones were erected: the Late Triassic (Rhaetian) Aratrisporites-Alisporites Assemblage, the Early Jurassic (Hettangian) Perinopollenites-Pinuspollenites Assemblage, and the Sinemurian Perinopollenites-Cycadopites Assemblage. The Tr-J boundary is placed between bed 44 and 45 coincident with the boundary between the Haojiagou and Badaowan formations. Beds with Ferganoconcha (?), Unio-Ferganoconcha id Waagenoperna-Yananoconcha bivalve assemblages are recognized. The Ferganoconcha (?) bed is limited to the upper Haojiagou Formation, Unio-Ferganoconcha and Waagenoperna-Yananoconcha assemblages are present in the middle and upper members of the Badaowan Formation. The sedimentary succession is interpreted as terrestrial with two mainly lake deposit intervals within Haojiagou and Badaowan formations, yielding fresh water algae and bivalves. However, the presence of brackish water algae Tasmanites and the marine-littoral facies bivalve Waagenoperna from the Badaowan Formation indicate that the Junggar Basin was influenced by sea water caused by transgressions from the northern Tethys, during the Sinemurian.
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- Söderlund, Ulf
(författare)
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Geochronology of Mafic Intrusions
- 2016
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Ingår i: Acta Geologica Sinica. - : Wiley. - 1000-9515. ; 90, s. 83-83
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Tidskriftsartikel (refereegranskat)
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