2nd Order Sequence Research Articles

Estratigrafia dos depósitos iniciais do rifte no Campo de Furado, região de São Miguel dos Campos, Bacia de Sergipe-Alagoas

Based on well logs, cuttings, cores and 3D seismic this work presents the 3rd order stratigraphic framework of the Feliz Deserto, Barra de Itiúba and Penedo formations and its relationship with the Furado Oilfield reservoir zones (Sergipe-Alagoas Basin). It also discusses the impact of tectonics on sedimentation during the early rifting stages. The J20-K5 Sequence (Candeeiro, Bananeiras and Serraria formations of the Dom João / Rio da Serra stages) comprise mostly shallow lacustrine and fluvial deposits that conformably change upwards to the K10-K20 Sequence (Feliz Deserto Formation of the Rio da Serra Stage), both making up a single 2nd order sequence. The K10-K20 sequences encompass shallow lacustrine facies that record a gradual growth on tectonic activity, as pointed by the upward change from parallel to divergent strata. The Pre-Aratu Unconformity bounds the K10-K20 and K34-K36 sequences and represents an important regional uplift event. A new subsidence pulse resulted in the deposition of the K34-K36 Sequence (Aratú to Buracica stages). Its lower 3rd order sequences encompass lacustrine and deltaic deposits and show evidence of higher-scale lake-level fluctuations relative to the K10-K20 Sequence. The upper 3rd order sequences represent the last stages of basin filling (coarse-grained fluvial deposits), the uppermost being equivalent to the Penedo Formation (Jiquiá Stage). Later, in the Alagoas Stage, a huge number of large, post-depositional normal faults deformed the entire succession although a gentle tectonic activity, related to fault propagation folding, a typical feature of early rifting, is identifiable since the late Rio da Serra Stage.

Depositional architecture of the late Ordovician drowned carbonate platform margin and its responses to sea-level fluctuation in the northern slope of the Tazhong region, Tarim Basin

The Tazhong Uplift of the late Ordovician is a drowned rimmed carbonate platform. the carbonate rock of the late Ordovician Lianglitage Formation in the northern slope of the Tazhong region is one of the significant petroliferous intervals. Based on petrofacies, depositional cycles, natural gammaray spectrometry and carbon/oxygen isotope data from the Lianglitage Formation, one 2nd-order, three 3rd-order and several 4th-order sequences have been recognized, and the late Ordovician relative sealevel fluctuation curve has been established. The sequences O3l-1 and O3l-2 on the platform are composed of highstand and transgressive systems tracts, but lack the lowstand systems tract. The sequence O3l-3 is a drowning sequence. The sequence O3l-1 overlapped the eroded slope and pinched out to the northwest and landward. The highstand systems tract in the sequence O3l-2 consists of low-angle sigmoid and high-angle shingled progradation configuration. Major sedimentary facies of the Lianglitage Formation include reef and shoal in the platform margin and lagoon, which can be subdivided into coral-sponge-stromatoporoid reef complex, sand shoal, lime mud mound, and intershoal sea. Reefs, sand shoals and their complex are potential reservoir facies. The reefs and sand shoals in the sequence O3l-1 developed in the upper of its highstand systems tract. In the sequence O3l-2, the highstand systems tract with an internal prograding configuration is a response to the lateral shifting of the complex of reef and sand shoal. The transgressive systems tract, in particular the sand shoals, developed widely on the slope of the platform margin and interior. The reefs in the sequence O3l-3 migrated towards high positions and formed retrograding reefs in the western platform and low relief in the platform interior. Basinward lateral migration of the reefs and pure carbonate rock both characterize highstand systems tract and show that the rise of the relative sea-level was very slow. Shingled prograding stacking pattern of the 4th-order sequences and reefs grow horizontally, which represents the late stage of highstand systems tract and implies relative sealevel stillstand. Reefs migrating towards high land and impure carbonate rock both indicate transgressive systems tract and suggest that the relative sea-level rose fast. Erosional truncation and epidiagenetic karstification represent a falling relative sea-level. The relative sea-level fluctuation and antecedent palaeotopography control the development and distribution of reef complexes and unconformity karst zones. Currently, the composite zone of epidiagenetic karstic intervals and high-energy complexes of reefs and sand shoals with prograding configuration is an important oil and gas reservoir in the northern slope of the Tazhong carbonate platform.

Sequence stratigraphic framework of Proterozoic successions in eastern Brazil

First-order regional unconformities separate Proterozoic supracrustal rocks of the gas-bearing São Francisco craton and surrounding thrust-and-fold belts (eastern Brazil) into four genetic stratigraphic units, which constitute 1st-order basin-fill sequences (Espinhaço, Canastra–Paranoá–Vazante, Macaúbas and Bambuí sequences). The Espinhaço 1st-order sequence (ca. 1.73–1.50 Ga) records a stage of aborted lithospheric stretching of the São Francisco-Congo continental mass. The Espinhaço basin displays a “steer's-head” geometry, where four 2nd-order sequences are recognized (prerift, rift, transitional and flexural). Third-order rift-propagation unconformities allowed the definition of three 3rd-order synrift sequences within the rift 2nd-order sequence. The 2nd-order flexural sequence of the Espinhaço basin can be subdivided into three 3rd-order transgressive–regressive sequences. The Canastra–Paranoá–Vazante and Macaúbas 1st-order sequences (ca. 1200–630 Ma) comprise rift to drift successions deposited during the breakup of the supercontinent Rodinia and the opening of the Brazilide and Adamastor oceans, respectively, to the west and east of the São Francisco paleocontinent. According to seismic data, the passive-margin Canastra–Paranoá–Vazante 1st-order sequence can be divided into two 2nd-order sequences: rift and passive margin. The passive-margin 2nd-order sequence can be further subdivided into three 3rd-order sequences. The outcropping Canastra–Paranoá–Vazante sequence consists mainly of shallow-marine deposits, which contain black shales/marls with intervals showing high total organic carbon (TOC) contents, comprising one of the highest potential hydrocarbon source rocks of the São Francisco basin. The Bambuí foreland 1st-order sequence (ca. 750–550 Ma) formed as a consequence of thrust loading related to shortening in the Brasília fold belt on the western flank of the São Francisco craton, during the closing of the Brazilide ocean and the assembly of the West Gondwana supercontinent. The Bambuí sequence shows two distinct successions, which reflect the main basin paleogeographic settings: foredeep and flexural ramp. Three transgressive–progradational 2nd-order sequences can be recognized in the ramp succession of the Bambuí basin.

Perceived Facial Expressions of Emotion as Motivational Incentives: Evidence From a Differential Implicit Learning Paradigm.

Participants (N = 216) were administered a differential implicit learning task during which they were trained and tested on 3 maximally distinct 2nd-order visuomotor sequences, with sequence color serving as discriminative stimulus. During training, 1 sequence each was followed by an emotional face, a neutral face, and no face, using backward masking. Emotion (joy, surprise, anger), face gender, and exposure duration (12 ms, 209 ms) were varied between participants; implicit motives were assessed with a picture-story exercise. For power-motivated individuals, low-dominance facial expressions enhanced and high-dominance expressions impaired learning. For affiliation-motivated individuals, learning was impaired in the context of hostile faces. These findings did not depend on explicit learning of fixed sequences or on awareness of sequence-face contingencies.

Neogene stratigraphic architecture and tectonic evolution of Wanganui, King Country, and eastern Taranaki Basins, New Zealand

Analysis of the stratigraphic architecture of the fills of Wanganui, King Country, and eastern Taranaki Basins reveals the occurrence of five 2nd order Late Paleocene and Neogene sequences of tectonic origin. The oldest is the late Eocene‐Oligocene Te Kuiti Sequence, followed by the early‐early Miocene (Otaian) Mahoenui Sequence, followed by the late‐early Miocene (Altonian) Mokau Sequence, all three in King Country Basin. The fourth is the middle Miocene to early Pliocene Whangamomona Sequence, and the fifth is the middle Pliocene‐Pleistocene Rangitikei Sequence, both represented in the three basins. Higher order sequences (4th, 5th, 6th) with a eustatic origin occur particularly within the Whangamomona and Rangitikei Sequences, particularly those of 6th order with 41 000 yr periodicity. The base of each 2nd order sequence is marked by marine flooding and represents a discrete phase in basin development. The Te Kuiti Sequence accumulated in non‐marine and shelf environments, whereas the Mahoenui Sequence accumulated mostly at bathyal depths; no regressive deposits are evident, having been eroded during subsequent uplift. The Mokau Sequence comprises shoreface and non‐marine deposits including coal measures. The Whangamomona Sequence accumulated during extensive flooding of King Country Basin and collapse of the eastern margin of Taranaki Basin. It has a thin retrogressive part (Otunui Formation) and a thick progradational component (Mount Messenger to Matemateaonga Formations). The latter component represents the northward progradation of a continental margin wedge through Wanganui and King Country Basins. The Rangitikei Sequence is marked by extensive flooding at its base (Tangahoe Mudstone) and reflects the pull‐down of the main Wanganui Basin depocentre. This sequence comprises a second progradational margin wedge, which migrated on two fronts, one northward through Wanganui Basin into King Country Basin, and a second west of the Patea‐Tongaporutu High, through the Toru Trough into the Central and Northern Grabens of Taranaki Basin and on to the Western Platform as the Giant Foresets Formation, thereby building up the modern shelf and slope. All five sequences are erosionally truncated, with up to 2100 m of exhumation that affected much of central North Island. The Pliocene timing of the start of erosion, together with its pattern, point to long wavelength deformation of the crust driven from the upper mantle consequent upon migration of the late Miocene andesitic volcanic arc from northern Taranaki Basin into Taupo Volcanic Zone.

Three orders of regional sea-level changes control facies and stacking patterns of shallow platform carbonates in the Maestrat Basin (Tithonian-Berriasian, NE Spain)

Middle Tithonian-Berriasian shallow platform carbonates of the Maestrat Basin (Salzedella and Montanejos sections, NE Spain) are stacked in sequence stratigraphic units of different orders. Higher-order sequences (parasequences and subunits) have a shallowing or deepening-shallowing evolution. They have been related to the short-term eccentricity and precession cycles. Major facies changes and stacking pattern of parasequences reveal the presence of two 2nd-order sequences. The Lower Sequence is middle Tithonian-mid early Berriasian in age. The Upper Sequence extends up to the mid-late Berriasian. It is suggested that local subsidence changes along with regional sea-level changes controlled the long-term evolution of accommodation in the Maestrat Basin. Facies evolution, stacking pattern and sharp lithological changes have allowed the definition of five 3rd-order sequences in the Lower Sequence in Montanejos. The transgressive deposits are characterised by the progressive absence of the restricted lagoon facies, and the presence of deepening-upward intervals in the parasequences. The highstand deposits display an increase in siliciclastics and a progressive predominance of restricted lagoon facies. Some of the 3rd-order sequence boundaries match the sequence boundaries identified in other European basins and may be related to sea-level falls (induced by the long-term eccentricity cycle) enhanced during periods of long-term loss of accommodation.

ABSTRACT: 2nd-Order Sequence Stratigraphy of Late Middle to Late Ordovician Montoya Group, southern New Mexico and West Texas

ABSTRACT: 2nd-Order Sequence Stratigraphy of Late Middle to Late Ordovician Montoya Group, southern New Mexico and West Texas

The Turonian rudist-bearingcarbonate platforms of the Charentes and Perigord areas, Aquitaine basin (France)

One of the most favourable periods for the expansion of rudists on the northern rim of the Aquitainebasin took place during the middle and the late Turonian within the Charentes and Périgord areas. This major period of rudist congregation development benefited from highly favourable conditions during the end of the first early Cenomanian - Late Turonian 2nd order sequence or “transgressive-regressive” cycle of the Aquitaine Late Cretaceous: an almost permanent regressive trend, sea-level highst and prograding wedges, and different palaeoenvironments from inner shelf to shoreline. About twenty species of rudists, particularly Radiolitidae and some scarce. Hippuritidae contributed to the establishment of two successive extensive carbonate inner-shelves, conformably overlying Lower Turonian rocks without rudists. Their total thickness ranges from 35 m up to 70 m (northeastern Charentes area), and they extend over an area 100 km × 25 km. The organization and the geodynamic evolution of these rudist-bearing formations were conditioned by the opposing influences of the open-sea, littoral or distal shoals and siliciclastic supplies, surrounding the inner-shelf. The rudists adjusted to the major biotope variations by changing their specific associations three times. The different phases of ground colonization, then proliferation and finally desertion of rudist congregations reflect the successive sedimentary facies within a shallow-water inner-shelf, protected by a barrier, some 30 km wide at least, made up of high-energy grainstone facies, often located along structural highs. Siliciclastic supply within the Périgord Noir area generally disrupted the development of the rudist assemblages during the late Turonian; however Hippurites requieni persisted and built widespread biostromes while small isolated Praeradiolites lived in muddy biotopes.

Abstract :Uppermost Jurassic and Cretaceous 2nd Order Sequence Boundaries in Brazilian Marginal Basins: Correlations with some Andean Basins and Implications 

Abstract :Uppermost Jurassic and Cretaceous 2nd Order Sequence Boundaries in Brazilian Marginal Basins: Correlations with some Andean Basins and Implications 

Lower Jurassic Sequence Stratigraphy and Sedimentary Facies on the North Slope of Mount Qomolangma

Abstract The Lower Jurassic is subdivided in ascending order into the Wulong, Kangdui and Yongjia Formations on the north slope of Mount Qomolangma, with a total thickness of 1362 m. They are thought to have been deposited respectively in the environments of the carbonate ramp fault–bounded basins and carbonate platform, with six sedimentary facies and six sub–facies. During the Early Jurassic, the Qomolangma area experienced strong faulting and subsidence, and was of a matured rift basin. The Lower Jurassic consists of eleven 3rd–order sequences, which can be grouped into three 2nd–order sequences and form a large transgressive–regressive cycle. The 3rd–order sequences and the corresponding sea–level changes recognized in the area can be correlated quite well with those set up in the western Tethys, and may have been caused by the eustatic fluctuations, while the 2nd–order sequences seem to be more closely related to the basement subsidence and the variation in sedimentary influx, indicating the evolution of the eastern Neotethys and the movement of the plates on its two sides.