Landslide hypothesis for the origin of Haleakala volcano's crater and great valleys, Hawaii

Active Haleakala volcano on the island of Maui is the second largest volcano in the Hawaiian Island chain. Prominently incised in Haleakala's slopes are four large (great) valleys. Haleakala Crater, a prominent summit depression, formed by coalescence of two of the great valleys. The great valleys and summit crater have long been attributed solely to fluvial erosion, but two significant enigmas exist in the theory. First, the great valleys of upper Keanae/Koolau Gap, Haleakala Crater, and Kaupo Gap are located in areas of relatively low annual rainfall. Second, the axes of some valley segments are oblique for long distances across the volcanic slopes. This study tested the prevailing erosional theory by reconstructing the volcano's topography just prior to valley incision. The reconstruction produces a belt along the volcano's east rift zone with a morphology that is inconsistent with volcanic aggradation alone, but it is readily explained if it is assumed the surface was displaced along scarps formed by a giant landslide on Haleakala's northeastern flank. Although the landslide head location is well defined, topographic evidence is lacking for the toe and lateral margins. Consequently, the slope failure is interpreted as a sackung-style landslide with a zone of deep-seated distributed shear and broad surface warping downslope of the failure head. Maximum downslope displacement was likely in the range of 400–800 m. Capture of runoff at the headscarps formed atypically large streams that carved Haleakala's great valleys and explains their existence in low-rainfall areas and their slope-oblique orientations. Sackung-style landslides may be more prevalent on Hawaiian volcanoes than previously recognized.

Determination of the Northwestern Extensions of the Bai Hassan Field (Daoud Culmination) and Its Geological Relationship with Ismail -1 Area, Northern Iraq

The Ismail-1 is located northwest of the Bai Hassan Field (Daoud Culmination), within the administrative boundaries of the provinces of Kirkuk and Erbil, which was later named Ismail Field. The objective of the research is to determine the geological relationship (structural and reservoir) of the well Ismail-1 with the Bai Hassan Field (Daoud Culmination). Based on geological and reservoir studies and seismic surveys of the region, the first basis of the research was based on the stratigraphy, structural, reservoir and morph structure aspects of this relationship.In the beginning, the serial sequence of the well was reviewed and compared with David's wells. Then, cross-sections and long sections were drawn through the wells of Ismail-1 and Daoud wells, as well as, the fluid levels dotted on such sections. After that, a structural contour map was drawn on top of Jeribe Formation for the area of well Ismail-1 which is currently known as Ismail Field and part of the Bai Hassan Field (Daoud Culmination), depending on the structural and reservoir data. It was found that the area of the well Ismail-1 is an asymmetrical convex fold, the southwestern flank is more inclined than the northeastern flank, and the Daoud Culmination and the Ismailfold is separated by a narrow saddle. However, depending on the structural contour map of the top of Jeribe Formation (-1325) meters from the mean sea level, the deeper levels of which surround the two Culminations together, the similarity of the reservoir properties and the different levels of fluid in the Daoud Culmination and the area of the Ismail-1, all confirm that they are two separate Culminations of one field. So the so-called Ismail Field can be considered a third Culmination called Ismail Culmination of the Bai Hassan Field.Using topographical maps and satellites data, the morph structure and geomorphological phenomena of the northwestern extensions of the Bai Hassan Field (the area of well Ismail-1) and towards the Quir Field, were studied and the northwestern aerial extensions of about 18 km length and 5 km width were delineated.Thus, the Bai Hassan Field is consisting of three Culminations (from the southeast to the northwest, Kithka, Daoud and Ismail Culminations) with a total length about 50 km.

THE FIRST EVIDENCE OF LATE DEVONIAN GRANITOID MAGMATISM IN THE NORTHEASTERN FLANK OF THE SOUTH MONGOLIA–KHINGAN OROGENIC BELT

The results of geochemical, U-Pb geochronological, Sm-Nd isotopic-geochemical studies of granites of the Medvedka Massif in the northern part of the Nora–Sukhotino terrane are presented. It has been found that these granites are of 378 ± 3 Ma in age. It was shown that these granites are characterized by the presence of ferruginous silicates, high iron index (FeO*/(FeO*+MgO)), low concentrations of Al2O3, CaO, MgO, high contents of Nb, Ga, Y, deficiency of Sr, Eu, positive values of εNd(t) (+3.0...+4.1), and high values of the ratio Y/Nb. In total, this indicates that the granites of the Medvedka massif are related to A2-type granites. The Late Devonian hastingsite-biotite granites of the Medvedka Massif most likely reflect evidence of the transform continental margin setting in the history of the formation of the South Mongolian – Khingan orogenic belt.

Seabed litter distribution in the high seas of the Flemish Pass area (NW Atlantic)

Seabed litter of the Flemish Pass area (NW Atlantic Ocean) was analysed and described using data from the EU-Spain groundfish survey (2006-2017 period). This study presents baseline information on seabed litter in this area. The Flemish Pass is located in areas beyond national jurisdiction within the Northwest Atlantic Fisheries Organization Regulatory Area Division 3L. A total of 1169 valid bottom trawl hauls were analysed (104-1478 m depth). Litter was found in 8.3% of the hauls, with mean densities of 1.4±0.2 items km–2 and 10.6±5.2 kg km–2. An increasing pattern with depth was found, the highest densities of seabed litter being identified in the deepest areas located in the Flemish Pass channel and down the northeastern flank of the Grand Bank. Fishing was found to be the main source of marine litter, and 61.9% of the hauls with litter presence showed litter included in the fisheries-related litter category. Whereas in most cases the litter was composed of small fragments of rope, in other cases it was composed of entire fishing gears such as traps. Plastics, metal and other anthropogenic litter were the next most abundant categories, accounting for 18.6%, 16.5% and 12.4% of the total, respectively.

The oldest turritelline gastropods: from the Oxfordian (Upper Jurassic) of Kutch, India

Turritellid gastropods are important components of many Cretaceous–Recent fossil marine faunas worldwide. Their shell is morphologically simple, making homoplasy widespread and phylogenetic analysis difficult, but fossil and living species can be recognized based on shell characters. For many decades, it has been the consensus that the oldest definite representatives of Turritellidae are from the Lower Cretaceous, and that pre-Cretaceous forms are homeomorphs. Some morphological characters of the present turritelline species resemble those of mathildoids, but many diagnostic characters clearly separate these two groups. We here describe and/or redescribe—based on examination of more than 2600 near complete specimens—four species from the Upper Jurassic Dhosa Oolite Member of the Chari Formation in Kutch, western India, and demonstrate that they are members of Turritellidae, subfamily Turritellinae, on the basis of diagnostic characters including apical sculptural ontogeny (obtained from SEM study), spiral sculpture, and growth line patterns. The four species are in order of abundance,Turritella jadavpuriensisMitra and Ghosh, 1979;Turritella amitavanew species;Turritella jhuraensisMitra and Ghosh, 1979, andTurritella dhosaensisnew species. The turritelline assemblages occur only on the northeastern flank of the Jhura dome (23°24’47.57”N, 69°36’09.26”E). Age of the Dhosa Oolite has recently been confirmed based on multiple ammonite species. All these points indicate that these fossils are the oldest record of the family Turritellidae—by almost 30 million years—in the world.