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The EW trending Yanshan belt, an intraplate fold‐thrust belt located in the northern North China Craton that has experienced several episodes of deformation widely separated in time, is characterized by out‐of‐sequence thrusts. According to detailed mapping in the central Yanshan belt, five geometric and stratigraphic criteria used to aid in determining whether a thrust has an out‐of‐sequence geometry or not can be recognized. They are (1) unconformable relationships, (2) inclination of fault surfaces, (3) irregular changes in apparent offset along strike, (4) short fault length relative to apparent offset, and (5) in‐sequence geometry. With the help of these criteria, two generations of out‐of‐sequence thrusts that postdate the original in‐sequence thrusting in the central Yanshan belt are recognized. The ancestral southward verging fold‐and‐thrust belt that formed prior to 180 Ma was deformed and cut by two younger generations of faults that are probably more deeply rooted and are constrained to between 172–165 Ma and 152–135 Ma. A series of thrusts with opposite vergence formed during the last period, resulting in abundant abnormal field relationships such as younger‐on‐older thrust relations, fold truncation, and cutting down‐section. The nature and occurrence of faults in the Yanshan belt implies that superimposed deformation, a common feature in polycyclic orogenic belts, is a mechanism for the generation of out‐of‐sequence thrusting. This adds to mechanisms already described in the literature, such as maintaining constant critical taper at an orogenic scale, inhibition of the deformation front, and lateral changes in the nature of the décollement horizons.

The plate tectonic history of the hypothesized "proto-South China Sea" (PSCS) ocean basin and surrounding SE Asia since Cenozoic times is controversial. We implement four diverse proto-South China Sea plate reconstructions into global geodynamic models to constrain PSCS plate tectonics and possible slab locations. Our plate reconstructions consider the following: southward versus double-sided PSCS subduction models; earlier (Eocene) or later (late Oligocene) initiation of Borneo counterclockwise rotations; and larger or smaller reconstructed Philippine Sea plate sizes. We compare our modeling results against tomographic images by accounting for mineralogical effects and the finite resolution of seismic tomography. All geodynamic models reproduce the tomographically imaged Sunda slabs beneath Peninsular Malaysia, Sumatra, and Java. Southward PSCS subduction produces slabs beneath present Palawan, northern Borneo, and offshore Palawan. Double-sided PSCS subduction combined with earlier Borneo rotations uniquely reproduces subhorizontal slabs under the southern South China Sea (SCS) at 400 to 700 km depths; these models best fit seismic tomography. A smaller Philippine Sea (PS) plate with ã 1,000-km-long restored Ryukyu slab was superior to a very large PS plate. Considered together, our four end-member plate reconstructions predict that the PSCS slabs are now at <900 km depths under present-day Borneo, the SCS, the Sulu and Celebes seas, and the southern Philippines. Regardless of plate reconstruction, we predict (1) mid-Cenozoic passive return-flow upwellings under Indochina; and (2) late Cenozoic downwellings under the SCS that do not support a deep-origin "Hainan plume." Modeled Sundaland dynamic topography strongly depends on the imposed plate reconstructions, varying by almost 1 km. Plain Language Summary The past motion of tectonic plates (i.e., plate tectonic reconstructions) is the source of fundamental boundary conditions for many studies of Earth history. The South China Sea lies at a key junction between NE and SE Asia, which is one of the most tectonically complex regions in the world. A great diversity of plate reconstructions has been proposed for the South China Sea area. In this work we assimilate multiple SE Asia plate tectonic reconstructions into numerical models of mantle convection, in the form of time-dependent velocity boundary conditions at the Earth's surface. This technique leads to a prediction for the time evolution of mantle structure and its flow field that is consistent with the reconstructed plate motions. Each reconstruction produces a different prediction of where subducted, colder oceanic lithosphere (i.e., slabs) should exist within the Earth's mantle. These predictions are transformed into a "synthetic" seismic tomography using published tomographic resolution filters and compared against seismic tomographic images of the Earth's mantle with special emphasis on the present South China Sea area, and its past plate tectonic history. For each plate reconstruction we also computed t...

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[1] The rainwater-induced change in phytoplankton biomass (FE1) and community growth rate (U1) in surface oceans is examined based on the incubation data. The results indicate that new production (NP) stimulated by atmospheric wet deposition (AWD) (i.e., AWD-NP) is strongly dependent on the nutrient concentrations and in situ phytoplankton biomass of surface waters. A positive relationship of FE1 and U1 against the amount of seawater nutrients (i.e., CE1) is found over a wide range of trophic states, which allows for estimating AWD-NP relative to standing stock and recycled oceanic production. Application of a FE1 -CE1 model shows that AWD-NP is comparable to the new production estimated by the N-15 technique in the East China Sea.