Second-order Sequences Research Articles

Sequence hierarchy in a Mesoproterozoic interior sag basin: from basin fill to reservoir scale, the Tombador Formation, Chapada Diamantina Basin, Brazil

AbstractThe Tombador Formation exhibits depositional sequence boundaries placed at the base of extensive amalgamated fluvial sand sheets or at the base of alluvial fan conglomeratic successions that indicate basinward shifts of facies. The hierarchy system that applies to the Tombador Formation includes sequences of different orders, which are defined as follows: sequences associated with a particular tectonic setting are designated as ‘first order’ and are separated by first‐order sequence boundaries where changes in the tectonic setting are recorded; second‐order sequences represent the major subdivisions of a first‐order sequence and reflect cycles of change in stratal stacking pattern observed at 102 m scales (i.e., 200–300 m); changes in stratal stacking pattern at 101 m scales indicate third‐order sequences (i.e., 40–70 m); and changes in stratal stacking pattern at 100 m scales are assigned to the fourth order (i.e., 8–12 m). Changes in palaeogeography due to relative sea level changes are recorded at all hierarchical levels, with a magnitude that increases with the hierarchical rank. Thus, the Tombador Formation corresponds to one‐first‐order sequence, representing a distinct intracratonic sag basin fill in the polycyclic history of the Espinhaço Supergroup in Chapada Diamantina Basin. An angular unconformity separates fluvial‐estuarine to alluvial fan deposits and marks the second‐order boundary. Below the angular unconformity the third‐order sequences record fluvial to estuarine deposition. In contrast, above the angular unconformity these sequences exhibit continental alluvial successions composed conglomerates overlain by fluvial and eolian strata. Fourth‐order sequences are recognized within third‐order transgressive systems tract, and they exhibit distinct facies associations depending on their occurrence at estuarine or fluvial domains. At the estuarine domain, they are composed of tidal channel, tidal bar and overlying shoreface heterolithic strata. At the fluvial domain the sequences are formed of fluvial deposits bounded by fine‐grained or tidal influenced intervals. Fine grained intervals are the most reliable to map in fourth‐order sequences because of their broad laterally extensive sheet‐like external geometry. Therefore, they constitute fourth‐order sequence boundaries that, at the reservoir approach, constitute the most important horizontal heterogeneity and, hence, the preferable boundaries of production zones. The criteria applied to assign sequence hierarchies in the Tombador Formation are based on rock attributes, are easy to apply, and can be used as a baseline for the study of sequence stratigraphy in Precambrian and Phanerozoic basins placed in similar tectonic settings.

Joint transmitter and receiver optimization for improper-complex second-order stationary data sequence

In this paper, the transmission of an improper-complex second-order stationary data sequence is considered over a strictly band-limited frequency-selective channel. It is assumed that the transmitter employs linear modulation and that the channel output is corrupted by additive proper-complex cyclostationary noise. Under the average transmit power constraint, the problem of minimizing the mean-squared error at the output of a widely linear receiver is formulated in the time domain to find the optimal transmit and receive waveforms. The optimization problem is converted into a frequency-domain problem by using the vectorized Fourier transform technique and put into the form of a double minimization. First, the widely linear receiver is optimized that requires, unlike the linear receiver design with only one waveform, the design of two receive waveforms. Then, the optimal transmit waveform for the linear modulator is derived by introducing the notion of the impropriety frequency function of a discrete-time random process and by performing a line search combined with an iterative algorithm. The optimal solution shows that both the periodic spectral correlation due to the cyclostationarity and the symmetric spectral correlation about the origin due to the impropriety are well exploited.

A Matching Method for Establishing Correspondence Between Satellite Radar Altimeter Data and Transponder Data Generated During Calibration

This letter presents a method for matching satellite radar altimeter data and transponder data generated during in situ calibration. The transponder generates a measurement error when it measures the arrival time of the altimeter's transmitted signal and embeds the error in both the transponder's recorded data and the altimeter's recorded data. The second-order finite difference sequence of this error sequence can be extracted from the raw data; thus, the correspondence between two identical but mismatched second-order difference sequences can be uniquely established. The measurement error is utilized, and a data matching method that can uniquely establish the correspondence between the altimeter's recorded data sequence and the transponder's recorded data sequence is presented. This postprocessing method does not increase the real-time signal processing workload of the transponder. Furthermore, the principles underlying this method can be used for any transponder that can adjust the response signal delay during calibration.

A pedagogical example of second-order arithmetic sequences applied to the construction of computer passwords by upper elementary grade students

The purpose of this paper is (1) to present how general education elementary school age students constructed computer passwords using digital root sums and second-order arithmetic sequences, (2) argue that computer password construction can be used as an engaging introduction to generate interest in elementary school students to study mathematics related to computer science, and (3) share additional mathematical ideas accessible to elementary school students that can be used to create computer passwords. This paper serves to fill a current gap in the literature regarding the integration of mathematical content accessible to upper elementary school students and aspects of computer science in general, and computer password construction in particular. In addition, the protocols presented here can serve as a hook to generate further interest in mathematics and computer science. Students learned to create a random-looking computer password by using biometric measurements of their shoe size, height, and age in months and to create a second-order arithmetic sequence, then converted the resulting numbers into characters that become their computer passwords. This password protocol can be used to introduce students to good computer password habits that can serve a foundation for a life-long awareness of data security. A refinement of the password protocol is also presented.

Sequence stratigraphic analyses of Naokelekan Formation (Late Jurassic), Barsarin area, Kurdistan region—Northeast Iraq

A sequence stratigraphic analysis of Naokelekan Formation (Late Jurassic succession) in Barsarin area, Kurdistan region, NE Iraq was constructed based on surface lithologic and thin section analyses. The formation consists of thin- to medium-bedded, black, bituminous limestones, and dolomitic limestone, intercalated with thin, black, calcareous shale in lower and upper parts. The petrographic study shows that the limestones are dominated by mudstones. The skeletal grains include ammonites, thin planktonic gastropods, forams (planktonics and benthonics), pelecypods, and ostracods. Non-skeletal grains include peloids. Facies analysis demonstrated an array of facies associations, which suggest deposition in subtidal (lagoon) environment in the lower and upper parts of the formation, and shallow open marine in its middle part. One second-order sequence can be identified, which comprises Middle and Upper Jurassic rock units. This sequence consists of two third order sequences. Third-order sequence 1 is represented by whole succession of underlying Sargelu Formation and lower part of Naokelekan Formation. While third order sequence two corresponds to middle and upper part of Naokelekan Formation. Each of the third-order sequences is comprised of transgressive and highstand system tracts. These system tracts in turn, consist of vertically stacked parasequences of shallowing upward packages.

Facies analysis and depositional environment study of the mixed carbonate–evaporite Asmari Formation (Oligo-Miocene) in the sequence stratigraphic framework, NW Zagros, Iran

The carbonate–evaporite mixed Asmari Formation was investigated on the three representative outcrops (these of Zarrin-abad, Abhar, and Darreh-shahr, corresponding to three sections) of the Lurestan Zone in NW Zagros, where the sedimentary facies of the Asmari Formation shows significant differences to those in other parts of Zagros. In the light of study results from the field observation and laboratory measurements, 16 facies have been recognized and differentiated, which are grouped into 5 facies associations, representing 6 sub-environments on a carbonate ramp. The sub-environments include peritidal area, lagoon, platform margin high-energy belts, middle ramp, outer ramp and evaporitic saltern. The evaporitic saltern points to such a condition, during which there occurred periodic change from carbonate to evaporitic settings. The alternation of carbonate with evaporitic settings appeared on a carbonate ramp connected with a hydrographically isolated intrashelf basin. The development of evaporite-dominated deposits of the Kalhur Member of Asmari Formation is related to the restriction of the basin during sea-level falls. This restriction led to succeeding evaporation of seawater and precipitation of evaporites. In times of sea-level rising, the basin was well reconnected to open ocean and thus the carbonate factory was reestablished over the basin. From sequence stratigraphic points of view, the formation is composed of two second-order regressive sequences, representing transitional conditions from deep-marine facies underlying Pabdeh Formation to shallow evaporitic facies overlying Gachsaran Formation. Each sequence is composed of a unit of evaporites at bottom displaying a falling-stage systems tract followed by thick carbonate strata, representing transgressive and highstand systems tracts. It is obvious that the major relative sea-level fall of the first second-order sequence was recorded by the facies development of the upper Kalhur gypsum of the Asmari Formation in the Zarrin-abad section, and there developed the paleokarst facies located at the sequence boundary in the Abhar, and Darreh-shahr sections.

Depositional model and evolution for a deep-water sublacustrine fan system from the syn-rift Lower Cretaceous Nantun Formation of the Tanan Depression (Tamtsag Basin, Mongolia)

Tanan Depression is a Cretaceous sub-basin in the Tamtsag Basin of eastern Mongolia. The early Cretaceous strata contain three second-order sequences and six third-order sequences deposited during the syn-rift phase. The primary target for petroleum exploration in the Lower Cretaceous Nantun Formation is a sublacustrine fan system deposited in a deep-water setting during the rift-climax stage corresponding to sequences SQ3 and SQ4. Based on drill cores, well logs, and seismic data, we identify two types of sublacustrine fans, nearshore and offshore fans, developed along the footwall scarp of this fault-bounded basin. A sediment feeder channel connects nearshore fans to offshore fans, which is supported by their similar provenance. We establish a model for a linked nearshore and offshore sublacustrine fan system in a deep-water setting for the Nantun Formation.The morphology of the sublacustrine fan system is revealed by recent advances in seismic data manipulation. The ascending cycle of sequence SQ4 in the upper Nantun Formation represents the most widespread development of sublacustrine fans among the deep lacustrine units of the sub-basin. Chronostratigraphic slices within the ascending cycle of sequence SQ4 reconstruct the depositional evolution of the sublacustrine fan system. These slices show that the deposition of the sublacustrine fan system increased during the lowstand period and then decreased during the transgressive period. Tectonics and sediment supply played a crucial role in the development of the sublacustrine fan system and its stacking patterns. In particular, during the lowstand period, a feeder channel carried sediments through nearshore sublacustrine fans into the deep basin. This led to the formation of offshore sublacustrine fans. We show that a combination of chronostratigraphic slices and a sequence stratigraphic framework is a good tool to reveal the high-resolution evolution of the sublacustrine fan system in response to systems tracts. Although middle fan zones of both nearshore and offshore sublacustrine fans have petroleum potential because of the high porosity and permeability of sedimentary rocks, the presence of a large-scale reservoir is unlikely.

Re-examining the role of context in implicit sequence learning.

Implicit sequence learning typically develops gradually, is often expressed quite rigidly, and is heavily reliant on contextual features. Recently we reported results pointing to the role of context-specific processes in the acquisition and expression of implicit sequence knowledge (D'Angelo, Milliken, Jiménez, & Lupiáñez, 2013). Here we examined further the role of context in learning of first-order conditional sequences, and whether context also plays a role in learning second-order conditional structures. Across five experiments we show that the role of context in first-order conditional sequences may not be as clear as we had previously reported, while at the same time we find evidence for the role of context in learning second-order conditional sequences. Together the results suggest that temporal context may be sufficient to learn complementary first-order conditional sequences, but that additional contextual information is necessary to concurrently learn higher-order sequential structures.

Paleogene tectonic evolution controls on sequence stratigraphic patterns in the central part of deepwater area of Qiongdongnan basin, northern South China Sea

In active rift basins, tectonism is extremely important for sequence stratigraphic patterns, affecting both the sequence architecture and internal makeup. Sequence stratigraphic framework of a Paleogene rift succession in Qiongdongnan Basin, northern South China Sea, was built using seismic profiles, complemented by well logs and cores. One first-order and three second-order sequences were identified on the basis of basin-scale unconformities, and seven third-order sequences are defined by unconformities along the basin margins and correlative conformities within the central basin. Through unconformity analysis and backstripping procedure, the Paleogene synrift tectonic evolution of deepwater area of Qiongdongnan Basin was proved to be episodic, which can be divided into rifting stage-I, rifting stage-II and rifting stage-III. Episodic rifting resulted in the formation of various types of structural slope break belts, which controlled different architectures and internal makeup of sequences. This study enhances the understanding of the control of tectonic evolution on sequence stratigraphic patterns and establishes relevant patterns in a typical rift basin, and further proposes the favorable sandstone reservoirs developing in different sequence stratigraphic patterns, which will be pretty helpful for subtle pool exploration in deepwater area of petroliferous basins.

Mapping sediment-dispersal characteristics using seismic geomorphology: Late Paleogene to Neogene, Qinan Sag, Huanghua Depression, China

The main objective of this article has been to demonstrate the utility of stratal slice images for exploring the sequence stratigraphy and sedimentology of complex depositional systems. The seismic-geomorphology study and sedimentary interpretation were performed to map sediment-dispersal characteristics from late Paleogene to Neogene in Qinan Sag, located in Huanghua Depression of China. The Qinan Sag is underlain by a non-marine Mesozoic and Cenozoic-age stratigraphic section. Main data types in this study area are lithology, wire-line logs and 3D seismic. The main study strata, Member one of Shahejie Formation to Minghuazhen Formation, divided into two second-order sequences and four third-order sequences. The older of the two second-order sequences, SE, corresponds to the formations from Kongdian to Dongying. The younger of the two second-order sequences, SN, correspond to Guantao and Minghuazhen formations. Guided by third-order sequence-stratigraphic correlations from seismic and wireline-log data, we prepared stratal slices from a three-dimensional seismic volume to reveal high-resolution (10-m) sediment dispersal characteristics in a relative geologic-time domain. Using techniques of 3-D seismic geomorphology, we defined four types of depositional systems: braided deltas, deltas, braided rivers and meandering rivers. Stratal slices indicated that the depositional evolution of these interest sequences was from braided-delta front to delta front, braided river and finally meandering river system. Many factors related to the structural evolution history controlled the sediment-dispersal characteristics, such as the basin type, dynamic mechanism, faulting activity, subsidence rate and paleo-high.

Sedimentary Facies of the First Member of Qingshankou-Formation in Late Cretaceous Songliao Basin of Daqing Oilfield China

According to core, logging and seismic data, using tectonic-stratigraphic and sequence stratigraphic analysise theories in Qingshankou Formation of division and comparison, and the sequence boundary and sequence unit to be optimized, in order to carry out seismic deposition. By determining the levels of sequence interface on seismic, logging and faces reflecting characteristics of the study area to build sequence interface identifier. In the course of practical work, identified the continental basin of the more common of the one to three levels of sequence interface, system interface and the parasequence set interface. In Songliao Basin, second-order sequences often corresponding to the tectonic evolution of the basin episodic stage, and in each period of prototype basin internal episodic tectonic extension or episodic of tectonic inversion is consistent, in Qingshankou Formation in the development of one second-order sequence boundary SB11 (T11), three third-order sequence boundary, there are SB12 (T12), SB13 (T13) and SB2 (T2), seven forth-order sequence boundary. In the plane, using the data of 256 wells, analysis of the distribution characteristics of the sedimentary facies of the first member of Qingshankou-Formation.

A Hierarchy of Responses to Auditory Regularities in the Macaque Brain

Can monkeys learn simple auditory sequences and detect when a new sequence deviates from the stored pattern? Here we tested the predictive-coding hypothesis, which postulates that cortical areas encode internal models of sensory sequences at multiple hierarchical levels, and use these predictive models to detect deviant stimuli. In humans, hierarchical predictive coding has been supported by studies of auditory sequence processing, but it is unclear whether internal hierarchical models of auditory sequences are also available to nonhuman animals. Using fMRI, we evaluated the encoding of auditory regularities in awake monkeys listening to first- and second-order sequence violations. We observed distinct fMRI responses to first-order violations in auditory cortex and to second-order violations in a frontoparietal network, a distinction only demonstrated in conscious humans so far. The results indicate that the capacity to represent and predict the structure of auditory sequences is shared by humans and nonhuman primates.

Tectono-sedimentary evolution and source rock distribution of the mid to Late Cretaceous succession in the Great South Basin, New Zealand

The Great South Basin, off New Zealand’s southeast coast, has attracted renewed exploration interest from major petroleum companies since 2005. The distribution of the mid Cretaceous to Paleocene source rocks (coals and coaly mudstones) is a critical component in evaluating basin prospectivity. This paper delineates source rock distribution from seismic facies characterisation, and presents a series of updated paleogeographic maps over the initial (Cretaceous) phases of basin evolution. Basin evolution has been analysed from mapped sequence stratigraphic boundaries and isochron maps. Seismic facies were characterised based on the amplitude, continuity, and stacking pattern of the reflection packages. The identified facies were calibrated with well data for age, gross lithology, and gross depositional environment. Areas of source rock deposition were demarcated using seismic attribute interval maps, from which a series of updated paleogeographic maps was prepared. Four second-order sequences have been identified within the Cretaceous succession. The lower two sequences are mainly fault bounded and were deposited in a syn-rift phase. In contrast, the upper two sequences reflect a change in basin character from rifting to a post-rift thermal sag phase. Source facies within both the syn- and post-rift sequences were deposited in mainly non-marine to marginal marine settings, although there is also the possibility of lacustrine source rocks in isolated syn-rift depocentres. The wide geographic spread of source rock intervals within the Cretaceous sequences allows for a variety of petroleum generation and exploration play scenarios.

Recognizing products of palaeoclimate fluctuation in the fluvial stratigraphic record: An example from the Pennsylvanian to Lower Permian of Cape Breton Island, Nova Scotia

Tectonics and climate are the major extrinsic upstream controls on both the external and internal architectures of fluvial channels. While the role of tectonics has been well-documented, the role of climate has received less attention. Because both tectonics and climate can produce similar stratigraphic architectures, the ability to recognize and differentiate these has major ramifications for the interpretation of fluvial stratigraphy. The Pennsylvanian to Permian succession of the Maritimes Basin complex on Cape Breton Island is ca 5 km thick, and is composed of predominantly non-marine strata deposited within a series of depocentres characterized by different subsidence regimes. Basins in the west are transtensional depocentres characterized by episodic fault movement. In contrast, basins in the east were formed during prolonged periods of passive thermal subsidence. The stratigraphy is composed of four second-order sequences (A to D), each 5 to 10 Myr in duration. These sequences are composed of amalgamated fluvial channel deposits that fine upwards into extensive mud-dominated floodplain deposits with isolated fluvial channel bodies. A spectrum of fluvial styles is recorded within the study area including perennial, perennial/intermittent and ephemeral. Four stratigraphic intervals (E1 to E4) are recognized in which the deposits of strongly seasonal perennial/intermittent fluvial deposits are predominant. These intervals, 2 to 6 Myr in duration, are correlated across the study area between basins with differing tectonic regimes and do not correlate with a particular position in second-order sequences. This suggests that climate exerted the dominant influence on the formation of these intervals and can be differentiated from tectonic imprints. While the tectonic regime of a particular basin exerted a fundamental control on the external architecture, a coherent record of climate change is recognized in the internal architecture of fluvial units. This study demonstrates that tectonic and climatic controls can be recognized and differentiated in vertical successions by evaluating the changes in fluvial architecture.

Three-dimensional facies architecture analysis using sequence stratigraphy and seismic sedimentology: Example from the Paleogene Dongying Formation in the BZ3-1 block of the Bozhong Sag, Bohai Bay Basin, China

The Bohai Bay Basin is a classic non-marine rift basin in eastern China. The Paleogene Dongying sequences are the main hydrocarbon-bearing stratigraphic unit in the basin. Using three-dimensional (3-D) seismic data and one well control in the BZ3-1 Block in the western slope of the Bozhong Sag, we analyzed 3-D facies architectures of the Dongying sequences. The Dongying Formation, a second-order sequence, can be subdivided into four third-order sequences (from base to top: SQ1, SQ2, SQ3, and SQ4). The facies architecture was analyzed by using the seismic sedimentology approach based on 3-D seismic data. Sediment of the Dongying sequences was derived from the northern Shijiutuo Uplift via four major configurations of incised valleys, namely “V”, “U”, “W”, and composite shaped incised valleys. Seismic stratal slices reveal branching and converging characteristics of the channels from upstream to downstream. On the basis of an integrated analysis of well log, core data, seismic facies based on multi-seismic attributes, three sedimentary facies (e.g., “delta”, “fan-delta”, and “shore” or “shallow lacustrine” facies) have been recognized. The four types of incised valleys and their evolution control the sedimentary systems in the sedimentation area. The numbers and sizes of the fans are controlled by the sedimentary systems at various scales. Incised valley-fill and deltaic sand bodies are excellent hydrocarbon reservoirs and potentially good exploration targets for the study area. The reservoir quality of sequences SQ1, SQ2, and SQ3 become better gradually from base to top. The proposed sediment dispersal patterns may aid in the prediction of potential reservoir distribution. This study also demonstrates that facies architecture analysis using sequence stratigraphy and seismic sedimentology may serve as an effective approach for constructing 3D facies models for petroleum exploration in areas lacking of well or outcrop data.

Tectonic Evolution and Sequence Filling of Paleocene in Lishui Sag, East China Sea Shelf Basin

The Lishui sag located at Southwest of the East China Sea Shelf Basin. It had undergone the four stages of syn-rift processes in Late Cretaceous to Paleocene: initial rift stage, main rift stage, stable rift stage and decline stage. The tectonic evolution has control effect on the development of sequence stratigraphy and the sediments distribution. Three second-order sequences, five third-order sequences and twelve system tracts are distinguished. Different sedimentary facies recognized in the Lishui sag.

Sequence-stratigraphic architectures and sand-body distribution in Cenozoic rifted lacustrine basins, east China

Cenozoic rifted lacustrine basins in east China display three main basin types: (1) basins with steeply dipping boundary fault, whose hanging walls tilt along pivot points; (2) basins with listric boundary faults, whose hanging walls bend along flexural bending points; and (3) basins formed by earlier extensional rifting with later strike-slip movement superimposed. The sequence development is intimately linked to the tectonic movements in the area, where second-order sequences are regionally correlatable from basin to basin and relate to the large-scale tectonic movements in the region. Third-order sequences are related to local tectonic activity and are correlatable within basins, between subbasins, and sometimes, between neighboring basins. Detailed sequence-stratigraphic analysis and mapping of depositional systems demonstrate that sand-body distribution patterns are related to sequence-stratigraphic frameworks. For the three kinds of basins, the positions of pivot point zones, flexural bend zones, and strike-slip faults plus the syndepositional faults all control the distribution of depositional systems, systems tract, and sand bodies. These controlling factors can be attributed to different structural and stratigraphic features that change the accommodation. Structural elements include boundary faults, syndepositional faults, and abrupt changes in dip. Stratigraphic controls include preexisting surfaces with local channelization, paleobathymetric lows, and onlap onto clinoform slopes. The lowstand sand bodies deposited at the downdip end of these controlling factors constitute the current and future exploration targets for conventional reservoirs.

Remarks on sequence stratigraphy and taphonomy of the Malvinokaffric shelly fauna during the KAČÁK Event in the Apucarana Sub-basin (Paraná Basin), Brazil

The Eifelian–Givetian (Middle Devonian) transition constituted an important paleoenvironmental event for the Malvinokaffric Realm in the Apucarana Sub-basin (Parana Basin). This study highlights integration between taphonomy and sequence stratigraphy, and four depositional sequences are identified during the transition. In Sequence 1, the presence of a typical normal-sized Malvinokaffric fauna is recorded. In the transgressive systems tract (TST) of Sequence 2, no benthic fossils are present, and this is interpreted as a stratigraphic marker of an event of significant paleoenvironmental change (KACAK Event). In Sequence 3, the TST has abundant bioclasts, which become rarer toward the top of the section, i.e., within the transgressive systems tract. The original habitat of this autochthonous to parautochthonous fauna was a low-energy environment between the fair weather wave base and the storm wave base of the Devonian epicontinental sea. In the highstand systems tract of this sequence, the presence of normal-sized Pennaia paulianna and lingulids demonstrates the return of more ambient conditions. Sequence 4 is of Carboniferous age. Its limit is a second-order sequence boundary recording a lowstand systems tract formed by a fluvial depositional system. The low diversity and the disappearance of taxa are not the result of a taphonomic bias, but reflect the post-KACAK Event.

On the Smarandache-Pascal derived sequences and some of their conjectures

For any sequence , the Smarandache-Pascal derived sequence of is defined as , , , generally, for all , where is the combination number. In reference (Murthy and Ashbacher in Generalized Partitions and New Ideas on Number Theory and Smarandache Sequences, 2005), authors proposed a series of conjectures related to Fibonacci numbers and its Smarandache-Pascal derived sequence, one of them is that if , then we have the recurrence formula , . The main purpose of this paper is using the elementary method and the properties of the second-order linear recurrence sequence to study these problems and to prove a generalized conclusion.

Controls on forearc basin architecture from seismic and sequence stratigraphy of the Upper Cretaceous Great Valley Group, central Sacramento Basin, California

Seismic and sequence stratigraphic analysis of deep-marine forearc basin fill (Great Valley Group) in the central Sacramento Basin, California, reveals eight third-order sequence boundaries within the Cenomanian to mid-Campanian second-order sequences. The third-order sequence boundaries are of two types: Bevelling Type, a relationship between underlying strata and onlapping high-density turbidites; and Entrenching Type, a significantly incised surface marked by deep channels and canyons carved during sediment bypass down-slope. Condensed sections of hemipelagic strata draping bathymetric highs and onlapped by turbidites form a third important type of sequence-bounding element, Onlapped Drapes. Five tectonic and sedimentary processes explain this stratigraphic architecture: (1) subduction-related tectonic tilting and deformation of the basin; (2) avulsion of principal loci of submarine fan sedimentation in response to basin tilting; (3) deep incision and sediment bypass; (4) erosive grading and bevelling of tectonically modified topography by sand-rich, high-density turbidite systems; and (5) background hemipelagic sedimentation. The basin-fill architecture supports a model of subduction-related flexure as the principal driver of forearc subsidence and uplift during the Late Cretaceous. Subduction-related tilting of the forearc and growth of the accretionary wedge largely controlled whether and where the Great Valley turbiditic sediments accumulated in the basin. Deeply incised surfaces of erosion, including submarine canyons and channels, indicate periods of turbidity current bypass to deeper parts of the forearc basin or the trench. Fluctuations in sediment supply likely also played an important role in evolution of basin fill, but effects of eustatic fluctuations were overwhelmed by the impact of basin tectonics and sediment supply and capture. Eventual filling and shoaling of the Great Valley forearc during early Campanian time, coupled with dramatically reduced subsidence, correlate with a change in plate convergence, presumed flat-slab subduction, cessation of Sierran arc volcanism, and onset of Laramide orogeny in the retroarc.