Xiangyang Xie

Plate tectonics and basin subsidence history

Tectonic setting exerts fi rst-order control on basin formation as refl ected in basin subsidence history. While our approach ignores the effects of fl exural loading and eustatic sea-level change, consistency of backstripped subsidence histories (i.e., with local loading effects of sediment removed) suggests consistent tectonic driving mechanisms in each tectonic setting, with the possible exception of forearc basins. Based on published subsidence curves and open-fi le stratigraphic data, we show the subsidence characteristics of passive margins, strike-slip basins, intracontinental basins, foreland basins, and forearc basins. Passive margin subsidence is characterized by two stages, rapid initial, synrift subsidence and slow post-rift thermal subsidence, with increasing subsidence rates toward the adjacent ocean basin. Subsidence of intracontinental basins is similar in magnitude to that seen in passive margin settings, but the former is generally slower, longer lived, and lacks initial subsidence. Long-lived subsidence for many intracontinental basins is consistent with cooling following thermal perturbation of thick lithosphere found beneath old parts of continents. Basins associated with strike-slip faults are usually short lived with very rapid subsidence. Changes in local stress regimes as strike-slip faults evolve, and migrate over time, coupled with three-dimensional heat loss in these small basins likely explain this subsidence pattern. Foreland basin subsidence rates refl ect the fl exural response to episodic thrust loading. Resultant subsidence curves are punctuated by convex-up (accelerating) segments. Forearc basins have the least consistent subsidence patterns. Subsidence histories of these basins are complex and may refl ect multiple driving mechanisms of subsidence in forearc settings. Second-order deviations in subsidence suggest reactivation or superimposed tectonic events in many basin settings. The effects of eustatic sea-level change may also explain some deviations in curves. For many of these settings, subsidence histories are suffi ciently distinctive to be used to help determine tectonic setting of ancient basin deposits.

U–Pb detrital zircon evidence of transcontinental sediment dispersal: provenance of Late Mississippian Wedington Sandstone member, NW Arkansas

ABSTRACT U–Pb ages of detrital zircons from the Wedington Sandstone member in northwest Arkansas provide evidence for Late Mississippian westward transcontinental sediment transport from the Appalachian foreland. The Late Mississippian Wedington Sandstone member of the Fayetteville Shale is a fine- to medium-grained quartzarenite. It separates the Fayetteville Shale into informal lower and upper intervals, and was deposited as a small constructive delta complex that prograded towards the south and southeast during the Late Mississippian. As a major influx of clastic sediments, the Wedington Sandstone member records the sediment source and dispersal in the mid-continent during the Late Mississippian. A total of 559 detrital zircon grains from six Wedington samples were recovered for U–Pb detrital zircon geochronological analysis. Results show that age distributions can be subdivided into six groups: ~350–500, ~900–1350, ~1360–1500, ~1600–1800, ~1800–2300, and > ~2500 Ma, and are characterized by a prominent peak for the age group of ~900–1350 Ma, a major peak at ~1600–1800 Ma, and a few other minor age clusters. Regional correlation and geological evidence from surrounding areas suggest that the transcontinental sediment dispersal started as early as the Late Mississippian. U–Pb detrital zircon age distribution suggests that the Wedington Sandstone member was likely derived from the Appalachian foreland with contributions from the Nemaha Ridge to the west where the Yavapai–Mazatzal sources were exposed during the Late Mississippian. Sediment was likely transported westward through or around the Illinois Basin, merged with mid-continent sediment, and then entered into its current location in northwest Arkansas. Transportation of this sediment from mixed sources continued along its course to the south, forming a delta on the Northern Arkansas Structural Platform.

Paleozoic sediment dispersal before and during the collision between Laurentia and Gondwana in the Fort Worth Basin, USA

We report detrital zircon U-Pb ages in the Fort Worth Basin (southern USA) aimed at understanding sediment dispersal patterns on the southern margin of Laurentia before and during the Laurentia-Gondwana collision. The ages from two Cambrian fluvial-marginal marine sandstone and six Pennsylvanian deltaic-fluvial sandstone samples span from Archean to early Paleozoic time. In the Cambrian sandstones, 80% of zircons are of Mesoproterozoic age (1.451– 1.325 Ga) and 18% are of Grenvillian age. The high abundance of the Mesoprotero zoic population suggests that the grains were dispersed by a local river draining the midcontinent granite-rhyolite province located in the Texas Arch to the northwest of the Fort Worth Basin. In the Pennsylvanian sandstones, 26% of zircons are of Archean–early Mesoproterozoic age, 47% are of Grenvillian age, 15% are of Neoproterozoic–earliest Paleozoic age (800–500 Ma), and 10% are of early Paleozoic age (500–318 Ma), indicating a different dispersal pattern during the Pennsylvanian relative to the Cambrian. Compared to other early Paleozoic detrital zircon records on the southern margin of Laurentia, our Pennsylvanian sandstones have a distinct age peak at ca. 650–550 Ma, which we interpreted to be a result of transport by local rivers draining a peri-Gondwana terrane, most likely the Sabine terrane in the Ouachita orogen. The high abundance of Grenvillian zircons reflects either direct transport from the Appa lachians by an axial river or recycling from Mississippian–Pennsylvanian sedimentary rocks incorporated in the Ouachita orogenic front. The similarity of detrital zircon age distributions in the Fort Worth Basin, the Arkoma Basin, and the southern Appalachian forelands seems to favor sediment dispersal by a major river with headwaters in the southern Appalachians.

Late Paleozoic Subsidence and Burial History of the Fort Worth Basin

ABSTRACT The Fort Worth basin in northcentral Texas is a major shale-gas producer, yet its subsidence history and relationship to the Ouachita fold-thrust belt have not been well understood. We studied the depositional patterns of the basin during the late Paleozoic by correlating well logs and constructing structure and isopach maps. We then modeled the one-dimensional (1-D) and two-dimensional subsidence history of the basin and constrained its relationship to the Ouachita orogen. Because the super-Middle Pennsylvanian strata were largely eroded in the region, adding uncertainty to the subsidence reconstruction, we used PetroMod 1-D to conduct thermal-maturation modeling to constrain the post-Middle Pennsylvanian burial and exhumation history by matching the modeled vitrinite reflectance with measured vitrinite reflectance along five depth profiles. Our results of depositional patterns show that the tectonic uplift of the Muenster uplift to the northeast of the basin influenced subsidence as early as the Middle Mississippian, and the Ouachita orogen became the primary tectonic load by the late Middle Pennsylvanian when the depocenter shifted to the east. Our results show that the basin experienced 3.7–5.2 km (12,100–17,100 ft) of burial during the Pennsylvanian, and the burial depth deepens toward the east. We attributed the causes of deep Pennsylvanian burial and its spatial variation to flexural subsidence that continued into the Late Pennsylvanian in response to the growth of the Ouachita orogen and southeastward suturing of Laurentia and Gondwana. The modeling results also suggest that the Mississippian Barnett Shale reached the gas maturation window during the Middle–Late Pennsylvanian.

Provenance of Permian Delaware Mountain Group, central and southern Delaware Basin, and implications of sediment dispersal pathway near the southwestern terminus of Pangea

ABSTRACT The Delaware Basin is located near the southwestern end of the Alleghanian–Ouachita–Marathon orogenic belt. The basin is mostly filled by Permian clastic rocks of the Delaware Mountain Group with ramp- to shelf-carbonate rimming basin edges. The Delaware Mountain Group has been well-documented as a deep-water clastic reservoir unit in the prolific Permian Basin, but its sources and related sediment dispersal pathways remain inconclusive. In this study, a total of 55 samples of the Delaware Mountain Group were collected from whole core and sidewall core from the central and southern Delaware Basin, and sandstone modal analyses and U-Pb detrital zircon geochronology were applied to constrain their potential sources. Sandstone modal analyses show that the majority of samples fall within the transitional continental source field. Age spectra of detrital zircon from five selected samples include a prominent middle Palaeozoic age cluster (~490–275 Ma), a major Neoproterozoic to early Palaeozoic age cluster (~790–510 Ma), and a series of minor age clusters of the middle to late Mesoproterozoic (~1300–920 Ma), early Mesoproterozoic (~1600–1300 Ma), late Palaeoproterozoic (~1825–1600 Ma), and Archaean and Palaeoproterozoic (> ~1825 Ma). Integrating detrital zircon data from all potential sources and coeval sandstones from the northern Delaware Basin suggests that the majority of sediment was derived from the Appalachian foreland, the Ouachita orogenic system, and the peri-Gondwanan terranes. Variation in the abundance of the different age groups reveals a provenance shift between deposition of the Brushy Canyon Formation and the Cherry and Bell Canyon Formations. To accommodate the composition, and the stratigraphic and spatial age spectral variations, we proposed that the sediment dispersal pathway includes a transcontinental fluvial system from the Appalachian orogenic belt to the east, a regional scale fluvial system from the Ouachita orogenic belt to the north and northeast, and a local, proximal fluvial system from the peri-Gondwanan terranes to the south and southeast.

U–Pb detrital zircon geochronology and Hf isotopic composition of Permian clastic rocks, Zhen’an basin, South Qinling belt: implications for the Paleozoic tectonic evolution of the Qinling orogenic belt

ABSTRACT Detrital zircon U–Pb geochronology, and Hf isotope compositional data for Permian strata near Xikou, Zhen’an in the South Qinling belt help constrain the tectonic evolutionary history of the Qinling Orogenic Belt. Results show that detrital zircons recovered from three sandstone samples share similar age-probabilities, including four age groups comprising 2100–1760 Ma (55.8%), 2750–2300 Ma (16.1%), 1200–770 Ma (12.3%), and 512–256 Ma (10.1%). By comparison with potential source areas, we conclude that Permian detrital zircons mainly originated from the southern margin of the North China Block, and probably the North Qinling belt as well, while the northern margin of the Yangtze Block did not supply detrital sediment. This distribution implies the South Qinling belt lay adjacent to the North Qinling belt and the North China Block by the Permian, but was separated from the Yangtze Block by the Mianlue Ocean, and support the Late Triassic collision between the Yangtze and North China Blocks.

U-Pb Detrital Zircon Geochronology of Late Triassic to Early Jurassic Sandstones in the Northwestern Junggar Basin and its Implications

The Junggar Basin is a Late Carboniferous foreland basin in northwestern China surrounded by different mountain belts. The west Junggar Basin has a complicated tectonic history with multiple subduction and collision events that controlled sedimentation and basin development. In this study, absolute dating of igneous rocks, rock geochemistry, and U-Pb detrital zircon geochronology were used to document the provenance of the Triassic-Jurassic clastic rocks in the northwest margin of Junggar Basin and determine local sources and tectonic setting. Granitic zircons with the youngest concordia age reveal the north Karamay pluton was formed at 292.6 ± 0.7 Ma, suggesting that they are postcollision granites. Late Triassic-Lower Early Jurassic strata were derived from Zhayier Mountain south of the Darbute fault. Starting with the Upper Early Jurassic Sangonghe Formation-Lower Middle Jurassic Xishanyao Formation, the strata changed from a single source to mix multiple sources. Sediment sources are widespread, including the northern Karamay granitic plutons, the area north of the Darbute fault, with potentially minor contributions from the southern margin of the Junggar Basin.