scholarly journals LITHOSTRATIGRAPHY OF THE NEWLY PROPOSED MIDDLE CRETACEOUS “BIBAI GROUP”, WESTERN SULAIMAN FOLD-THRUST BELT, PAKISTAN

2021 ◽  
Vol 5 (2) ◽  
pp. 34-39
Author(s):  
Kifayat Ullah Shah ◽  
Akhtar Muhammad Kassi ◽  
Aimal Khan Kasi
Keyword(s):  
North American ◽  
Volcanic Rocks ◽  
Thrust Belt ◽  
Volcanic Group ◽  
The North ◽  
Lithostratigraphic Units ◽  
The Status ◽  
Stratigraphic Nomenclature ◽  
Volcaniclastic Succession

The newly proposed Middle Cretaceous “Bibai Group”, named after the Bibai peak, is exposed in Kach-Ziarat, Spera Ragha-Chingun areas of the Western Sulaiman Fold-Thrust Belt, Pakistan. It comprises thick succession of the mafic volcanic rocks, volcanic conglomerate, mudstone and sandstone. The stratigraphic nomenclature proposed by previous workers was not clear enough, as they used different names for the succession, such as “Kahan Conglomerate Member” of the Mughal Kot Formation, “Parh-related volcanics” by considering it as part of the “Parh Group, “Bibai Formation” and “Bela Volcanic Group”, which were confusing and misleading. Also previous workers did not realize that the succession may be further classified into distinct mappable lithostratigraphic units and deserved the status of a “Group”. Therefore, we carefully examined and mapped the area and hereby propose the name “Bibai Group” for the overall volcanic and volcaniclastic succession of the Middle Cretaceous age. Based on distinct lithostratigraphic characters we further subdivided the “Group” into two lithostratigraphic units of formation rank, for which we propose the names “Chinjun Volcanics” and “Bibai Formation”. Also based on distinct lithostratigraphic characters we further propose to subdivide our “Babai Formation” into three lithostratigraphic units of member rank, which we named as the “Kahan Conglomerate Member”, “Ahmadun Member” and “Kach Mudstone Member”. In this paper we have defined and briefly described the Bibai Group, its constituent formations and their members. Also we examined and discussed the validity and status of the proposed subdivisions; e.g. formations and members, of the Bibai Group, and are fully satisfied that the proposed subdivisions are appropriate and comply with the Article 24 and 25 of the North American Stratigraphic Codes (2005) and that the previous nomenclatures are inconsistent, confusing and do not comply with the International Stratigraphic Codes.

The North American Allies of Hylobius piceus (De Geer) (Coleoptera: Curculionidae)

1957 ◽  
Vol 89 (1) ◽  
pp. 37-43 ◽  
Author(s):  
Stephen L. Wood
Keyword(s):  
North American ◽  
Distinct Species ◽  
Morphological Characters ◽  
North American Species ◽  
Winged Form ◽  
The North ◽  
The Status ◽  
Field Workers ◽  
Dimorphic Species ◽  
Biological Differences

While investigating the biology of the North American species of Hypomolyx, field workers in Manitoba found a vestigial, or short-winged, and a long-winged form under apparently identical conditions in about equal numbers. Although biological differences were nor then apparent, there was doubt as to whether they were dealing with one dimorphic species or with two distinct species, A search for morphological characters brought to light numerous differences between the two forms, supporting the view that two species were present. These differences, a description the previously unrecognized species, and notes concerning the status of the genera Hylobius and Hypomolyx are reported below.

scholarly journals A revised lithostratigraphy for the Palaeogene – lower Neogene of the Danish North Sea

2005 ◽  
Vol 7 ◽  
pp. 21-24
Author(s):  
Poul Schiøler ◽  
Jan Andsbjerg ◽  
Ole R. Clausen ◽  
Gregers Dam ◽  
Karen Dybkjær ◽  
...  
Keyword(s):  
North Sea ◽  
Energy Agency ◽  
Sequence Stratigraphic ◽  
Oil Companies ◽  
The North ◽  
Reference Sections ◽  
Stratigraphic Model ◽  
Lithostratigraphic Units ◽  
The North Sea ◽  
Stratigraphic Nomenclature

Intense drilling activity following the discovery of the Siri Field in 1995 has resulted in an improved understanding of the siliciclastic Palaeogene succession in the Danish North Sea sector (Fig. 1). Many of the new wells were drilled in the search for oil reservoirs in sand bodies of Paleocene–Eocene age. The existing lithostratigraphy was based on data from a generation of wells that were drilled with deeper stratigraphic targets, with little or no interest in the overlying Palaeogene sediments, and thus did not adequately consider the significance of the Palaeogene sandstone units in the Danish sector. In order to improve the understanding of the distribution, morphology and age of the Palaeogene sediments, in particular the economically important sandstone bodies, a detailed study of this succession in the Danish North Sea has recently been undertaken. An important aim of the project was to update the lithostratigraphic framework on the basis of the new data.The project was carried out at the Geological Survey of Denmark and Greenland (GEUS) with participants from the University of Aarhus, DONG E&P and Statoil Norway, and was supported by the Danish Energy Agency. Most scientific results cannot be released until September 2006, but a revised lithostratigraphic scheme may be published prior to that date. Formal definition of new units and revision of the lithostratigraphy are in preparation. All of the widespread Palaeogene mudstone units in the North Sea have previously been formally established in Norwegian or British wells, and no reference sections exist in the Danish sector. As the lithology of a stratigraphic unit may vary slightly from one area to another, Danish reference wells have been identified during the present project, and the lithological descriptions of the formations have been expanded to include the appearance of the units in the Danish sector. Many of the sandstone bodies recently discovered in the Danish sector have a limited spatial distribution and were sourced from other areas than their contemporaneous counterparts in the Norwegian and British sectors. These sandstone bodies are therefore defined as new lithostratigraphic units in the Danish sector, and are assigned Danish type and reference sections. There is a high degree of lithological similarity between the Palaeogene–Neogene mudstone succession from Danish offshore boreholes and that from onshore exposures and boreholes, and some of the mudstone units indeed seem identical. However, in order to acknowledge the traditional distinction between offshore and onshore stratigraphic nomenclature, the two sets of nomenclature are kept separate herein. In recent years oil companies operating in the North Sea have developed various in-house lithostratigraphic charts for the Paleocene–Eocene sand and mudstone successions in the Danish and Norwegian sectors. A number of informal lithostratigraphic units have been adopted and widely used. In the present project, these units have been formally defined and described, maintaining their original names whenever feasible, with the aim of providing an unequivocal nomenclature for the Palaeogene – lower Neogene succession in the Danish sector. It has not been the intention to establish a sequence stratigraphic model for this succession in the North Sea; the reader is referred to the comprehensive works of Michelsen (1993), Neal et al. (1994), Mudge & Bujak (1994, 1996a, b), Michelsen et al. (1995, 1998), Danielsen et al. (1997) and Rasmussen (2004).

Paleomagnetism of the Lawrenceton Formation volcanic rocks, Silurian Botwood Group, Change Islands, Newfoundland

1989 ◽  
Vol 26 (2) ◽  
pp. 296-304 ◽  
Author(s):  
Julie E. Gales ◽  
Ben A. van der Pluijm ◽  
Rob Van der Voo
Keyword(s):  
North American ◽  
Volcanic Rocks ◽  
Mobile Belt ◽  
Structural Mapping ◽  
Polar Wander ◽  
The North ◽  
Apparent Polar Wander Path ◽  
Paleomagnetic Study ◽  
North American Craton

Paleomagnetic sampling of the Lawrenceton Formation of the Silurian Botwood Group in northeastern Newfoundland was combined with detailed structural mapping of the area in order to determine the deformation history and make adequate structural corrections to the paleomagnetic data.Structural analysis indicates that the Lawrenceton Formation experienced at least two folding events: (i) a regional northeast–southwest-trending, Siluro-Devonian folding episode that produced a well-developed axial-plane cleavage; and (ii) an episode of local north-trending folding. Bedding – regional cleavage relationships indicate that the latter event is older than the regional folding.Thermal demagnetization of the Lawrenceton Formation yielded univectorial southerly and shallow directions (in situ). A fold test on an early mesoscale fold indicates that the magnetization of the Botwood postdates this folding event. However, our results, combined with an earlier paleomagnetic study of nearby Lawrenceton Formation rocks, demonstrate that the magnetization predates the regional folding. Therefore, we conclude that the magnetization occurred subsequent to the local folding but prior to the period of regional folding.While a tectonic origin for local folding cannot be entirely excluded, the subaerial nature of these volcanics, the isolated occurrence of these folds, and the absence of similar north-trending folds in other areas of eastern Notre Dame Bay suggest a syndepositional origin. Consequently, the magnetization may be nearly primary. Our study yields a characteristic direction of D = 175°, I = +43°, with a paleopole (16°N, 131 °E) that plots near the mid-Silurian track of the North American apparent polar wander path. This result is consistent with an early origin for the magnetization and supports the notion that the Central Mobile Belt of Newfoundland was adjacent to the North American craton, in its present-day position, since the Silurian.

Early Sevier orogenic deformation exerted principal control on changes in depositional environment recorded by the Cretaceous Newark Canyon Formation

2020 ◽  
Vol 90 (9) ◽  
pp. 1175-1197
Author(s):  
Anne C. Fetrow ◽  
Kathryn E. Snell ◽  
Russell V. Di Fiori ◽  
Sean P. Long ◽  
Joshua W. Bonde
Keyword(s):  
North American ◽  
Global Climate ◽  
Sedimentary Basins ◽  
River System ◽  
Structural Deformation ◽  
Braided River ◽  
Thrust Belt ◽  
North American Cordillera ◽  
The North

ABSTRACT Terrestrial sedimentary archives record critical information about environment and climate of the past, as well as provide insights into the style, timing, and magnitude of structural deformation in a region. The Cretaceous Newark Canyon Formation, located in central Nevada, USA, was deposited in the hinterland of the Sevier fold–thrust belt during the North American Cordilleran orogeny. While previous research has focused on the coarser-grained, fluvial components of the Newark Canyon Formation, the carbonate and finer-grained facies of this formation remain comparatively understudied. A more complete understanding of the Newark Canyon Formation provides insights into Cretaceous syndeformational deposition in the Central Nevada thrust belt, serves as a useful case study for deconvolving the influence of tectonic and climatic forces on sedimentation in both the North American Cordillera and other contractional orogens, and will provide a critical foundation upon which to build future paleoclimate and paleoaltimetry studies. We combine facies descriptions, stratigraphic measurements, and optical and cathodoluminescence petrography to develop a comprehensive depositional model for the Newark Canyon Formation. We identify six distinct facies that show that the Newark Canyon Formation evolved through four stages of deposition: 1) an anastomosing river system with palustrine interchannel areas, 2) a braided river system, 3) a balance-filled, carbonate-bearing lacustrine system, and 4) a second braided river system. Although climate undoubtedly played a role, we suggest that the deposition and coeval deformation of the synorogenic Newark Canyon Formation was in direct response to the construction of east-vergent contractional structures proximal to the type section. Comparison to other contemporary terrestrial sedimentary basins deposited in a variety of tectonic settings provides helpful insights into the influences of regional tectonics, regional and global climate, catchment characteristics, underlying lithologies, and subcrop geology in the preserved sedimentary record.

Revision of the North American species of the genus Entomacis (Hymenoptera: Diapriidae)

2004 ◽  
Vol 136 (3) ◽  
pp. 323-405 ◽  
Author(s):  
Matthew J. Yoder
Keyword(s):  
North America ◽  
North American ◽  
Species Group ◽  
North American Species ◽  
The North ◽  
The Status ◽  
Group Members ◽  
Character Complexes ◽  
Species Taxonomy ◽  
North America North

AbstractThe species of the genus Entomacis Foerster in North America north of Mexico are revised. Nineteen species (12 new), including 8 species of the Holarctic-wide perplexa species group, are keyed, described, and figured. These taxa are E. ambigua (Brues), E. apopkaensissp. nov., E. arcticasp. nov., E. cellariasp. nov., E. cepasp. nov., E. eorariasp. nov., E. floridana (Ashmead), E. grandiclavasp. nov., E. longii (Ashmead), E. mellipetiola (Ashmead), E. parambiguasp. nov., and perplexa group members E. californica (Ashmead), E. microbipunctatasp. nov., E. notioxerasp. nov., E. oulasp. nov., E. parvasp. nov., E. perplexa (Haliday), E. sapratasp. nov., and E. subemarginata (Ashmead). Hemilexodes canadensis (Harrington) is synonymized under Entomacis mellipetiola (Ashmead) (syn. nov.). The status of Entomacis latipennis (Ashmead), E. filiformis (Ashmead), and Hemilexis jessei Mann is reviewed. New character complexes, particularly chaetotaxy, are emphasized for Diapriidae species taxonomy.

Categorization of Korean Language Collections Level of North American Research Universities

Libri ◽  
2016 ◽  
Vol 66 (2) ◽  
Author(s):  
Jane Cho
Keyword(s):  
Statistical Analysis ◽  
North American ◽  
Research Universities ◽  
High Potential ◽  
Korean Language ◽  
The North ◽  
The Status ◽  
American Research ◽  
International Status ◽  
American Region

AbstractAs a result of increased interest in the international status and culture of Korea, Koreanology is growing among research universities in the North American region. Though the number of Korean language collections is increasing, it is still at a level of one-seventh and one-fourth of Sinology and Japanology, respectively. Taking the overall view of the status of Korean language collections operated by research universities in the North American region through statistical analysis, this study pinpointed the library clusters that the Korean government needs to support strategically by categorizing their advancement forms. As a result, it was found that there are universities which have a high potential for Koreanology to advance as the setup level of the major is high, but they have low library operation levels, and in such clusters there is no librarian specialized in Koreanology.

NORTH AMERICAN COMMISSION ON STRATIGRAPHIC NOMENCLATURE Report 14 - Revision of Articles 73, 81, 82 and Table 2 of the North American Stratigraphic Code to Formalize Subseries and Subepochs

Stratigraphy ◽  
2020 ◽  
pp. 315-316
Author(s):  
Marie-Pierre Aubry ◽  
Richard Fluegeman ◽  
Lucy Edwards ◽  
Brian R. Pratt ◽  
Carlton E. Brett
Keyword(s):  
Annual Meeting ◽  
North American ◽  
The North ◽  
Red Color ◽  
One Year ◽  
Stratigraphic Nomenclature

At the 75th Annual Meeting of the North American Commission on Stratigraphic Nomenclature, 22 October, 2020, in connection with GSA 2020 Connects Online, the Commission voted unanimously to accept the revision of Articles 73, 81 and 82 of the North American Stratigraphic Code (North American Commission on Stratigraphic Nomenclature, 2005 with subsequent updates), and concomitant changes to Table 2; specific revisions of the Code are indicated in red color. These replace all older versions of the specified Articles. An application for this revision (Aubry et al. 2019) was published in Stratigraphy more than one year prior to the meeting; thus, the vote on this application for revision follows Article 21 of the Code.

The separation of Carex disticha and Carex sartwellii and the status of Carex disticha in North America

1988 ◽  
Vol 66 (11) ◽  
pp. 2323-2330 ◽  
Author(s):  
P. M. Catling ◽  
A. A. Reznicek ◽  
B. S. Brookes
Keyword(s):  
North American ◽  
Principal Component ◽  
Small Region ◽  
Morphological Characters ◽  
Scatter Diagram ◽  
The North ◽  
The Status ◽  
Beak Length ◽  
The Relationship ◽  
Distinguishing Features

To clarify the relationship between the Eurasian Carex disticha and the North American Carex sartwellii, 38 morphological characters were measured in 30 specimens of each. Various qualitative features were also scored. Through analysis of variance (ANOVA), a reduced number of 10 important continuous characters was obtained and the sample of each taxon was increased to 50. ANOVA of these 10 characters revealed that perigynium length and perigynium beak length were the most important discriminating characters, but in a scatter diagram of these two, 15% of the sample occupied a region of overlap. Principal-component analysis and discriminant analysis using the 10 characters resulted in a separation of the two groups, but a small region of overlap existed in both cases. The two taxa are distinct by virtue of accumulation of small morphological and other differences in a number of characters, rather than by sharp differentiation in a few characters. Carex disticha has larger perigynia with beaks (0.8–)1–1.5(–2.3) mm long, whereas C. sartwellii has smaller perigynia with beaks 0.4–1(–1.2) mm long. All distinguishing features are discussed and a key is provided. Immature vouchers for the occurrence of C. disticha in southwestern Quebec are confirmed on the basis of features of the inflorescence. The only other North American station of C. disticha, discovered in Simcoe Co., Ontario, in 1972 and extant in 1986, is also confirmed in the numerical analyses.

Sign in / Sign up

Export Citation Format

Share Document