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Euler deconvolution of potential field data is widely applied to obtain the location of concealed sources automatically. A lot of improvements have been proposed to eliminate the dependence of Euler deconvolution on the structural index that are based on the use of high‐order derivatives of the potential field and, therefore, sensitive to data noise. We describe the elimination of the dependence on the Ratio‐Euler method, which is based on the original Euler deconvolution function. The proposed method does not involve high‐order derivatives. Testing on simulated and field data indicates that the proposed method has better noise resistance than the existing Tilt‐Euler method, which is based on high‐order derivatives. The proposed method is first applied to the ground magnetic data from Weigang iron deposit, Eastern China. It reveals that the ore body could be approximated by a horizontal prism with a considerable vertical extent with a top depth of 55 m, which are very close to the information obtained from drill holes. In addition, the proposed method works well in estimating the depth to a cavity centre from the ground gravity anomaly. [ABSTRACT FROM AUTHOR]

This work integrates processing and interpretation of the combined geomagnetic anomaly model of NGDC-720-V3.1 to better constrain thermal structures of the Northeast China lithosphere, which shows intensive extension and active volcanism during the Mesozoic and Cenozoic. Numerical tests demonstrate that magnetic anomalies calculated at 20 km altitude can be used for accurate Curie depth estimation. Averaged Curie depths using a 3D fractal exponent of 3.0 vary from ∼ 13 ± 2.0 to 33 ± 4.1  km with a mean of ∼ 22 ± 2.4  km in Northeast China. With temperature-dependent thermal conductivity models constrained by incorporated surface heat flow and Curie depths in different geological blocks, the thermal lithospheric thicknesses are estimated mostly between 45 and 90 km based on 1D steady-state thermal conduction equation. Beneath the Songliao Basin, the Moho temperatures are abnormally high, ranging from ca. 700 to 1000 °C, and the mantle contributes about 65% of the total surface heat flow. The shallow Curie points and thermal lithosphere-asthenosphere boundary, together with high Moho temperatures and mantle heat flow, support abnormally high geotherms in the Songliao Basin, originated from hot upper mantle upwelling triggered likely by lithospheric delamination. [ABSTRACT FROM AUTHOR]

The Wunugetushan porphyry Cu-Mo deposit is located in northeastern China. The deposit lies within the Mongolia-Erguna metallogenic belt, which is associated with the evolution of the Mongol-Okhotsk Ocean. The multiple episodes of magmatism in the ore district, occurred from 206 to 173 Ma, can be divided into pre-mineralization stage (biotite granite), mineralization stage (monzogranitic porphyry and rhyolitic porphyry), and post-mineralization stage (andesitic porphyry). The biotite granite has (87Sr/86Sr)i values of 0.704105-0.704706, εNd(t) values of -0.67 to -0.07, and εHf(t) values of -0.4 to 2.8, yielding Hf two-stage model ages (TDM2) 1250-1067 Ma, and Nd model ages of 1.04-0.96 Ga, indicating that the pre-mineralization magmas were generated by the remelting of Neoproterozoic juvenile crustal material. The monzogranitic porphyry has (87Sr/86Sr)i values of 0.704707-0.706134, εNd(t) values of 0.29-1.33, and εHf(t) values of 1.0-2.9, yielding TDM2 model ages of 1173-1047 Ma. The rhyolitic porphyry has (87Sr/86Sr)i ratio of 0.702129, εNd(t) value of -0.21, and εHf(t) values of -0.5 to 7.1, TDM2 model ages from 1269 to 782 Ma. These results show that the magmas of mineralization stage were generated by the partial melting of juvenile crust mixed with mantle-derived components. The andesitic porphyry has (87Sr/86Sr)i ratio of 0.705284, εNd(t) value of 0.82, and εHf(t) values from 4.1 to 7.4, indicating that the post-mineralization magma source contained more mantle-derived material. The Mesozoic Cu-Mo deposits which genetically related to Mongol-Okhotsk Ocean were temporally distributed in Middle to Late Triassic (240- 230 Ma), Early Jurassic (200-180 Ma), and Later Jurassic (160-150 Ma) period. The Middle Triassic to Early Jurassic Cu-Mo mineralization was dominated by Mongol-Okhotsk oceanic plate southeastdirected subducted beneath the Erguna massif. The Later Jurassic Cu-Mo mineralization was controlled by the continent-continent collision between Siberia plate and Erguna massif. [ABSTRACT FROM AUTHOR]

The article discusses a workshop entitled "Unlocking the Opening Processes of the South China Sea" sponsored by Integrated Ocean Drilling Program, the National Natural Science Foundation of China and Tongji University, China that was held in Shanghai, China from January 31, 2012 to February 1, 2012. The workshop featured sixty-five participants from 15 countries and regions around South China Sea. Its main aim was to develop efficient research and drilling strategy for geological projects.

Cenozoic igneous rocks dominated by basalts are exposed sporadically onshore East China, and they provide important information about the Cenozoic evolution of the region. Importantly, their geometries and distribution are still not well constrained in the 200–600 km wide offshore continental shelf region. Based on seismic profiles, this study presents the geometric characteristics of 133 igneous sills that are widely distributed in the central and southern regions of the East China Sea Shelf Basin (ECSSB). Sills in high-amplitude, continuous seismic reflections mostly occur in a time interval of 1.1–3.3 s in multiple seismic profiles, corresponding to a depth range of 1.1–4.8 km. They can be classified into five types: saucer-shaped sills, strata-concordant sills, laccoliths, inclined sheets, and hybrid sills. Of these, the saucer-shaped sills predominate. Strata deformation associated with these igneous sills indicate that sill intrusion has become intense since the Miocene, and it potentially affected petroleum systems in the ECSSB. Forced folds induced by the sills are prospective petroleum traps. We infer that sill intrusion in the ECSSB was due to magma upwelling caused by dehydration and/or small-scale convection in a large mantle wedge above the stagnant Pacific slab. The subduction of the Philippine Sea plate resulted in tectonic inversion in the ECSSB and extension in the Okinawa Trough since the Early Miocene triggered more magmatism in the tectonically thinned ECSSB. Thick sedimentary strata over a thin crust in the ECSSB may have induced more intrusive than extrusive Cenozoic magmatism. • Sill geometry and distribution in the central and southern ECSSB are presented for the first time. • Igneous sills are common in the ECSSB and can be classified into five geometric types. • Sill intrusion in the ECSSB became intense since the Miocene. [ABSTRACT FROM AUTHOR]