scholarly journals Volutoderminae (Gastropoda: Volutidae) of Coniacian through Maastrichtian age from the North American Pacific Slope

2008 ◽  
Vol 82 (2) ◽  
pp. 213-237 ◽  
Author(s):  
Louella R. Saul ◽  
Richard L. Squires
Keyword(s):  
San Francisco ◽  
Late Cretaceous ◽  
Gulf Coast ◽  
Shallow Marine ◽  
The North ◽  
Rudist Bivalves ◽  
Pacific Slope ◽  
Warm Temperate ◽  
World Distribution ◽  
A New Species

Specimens of the large, shallow-marine, volutid gastropod Volutoderma Gabb, 1877, herein recognized only from strata of Late Cretaceous (Coniacian through early Maastrichtian) age in British Columbia, Washington, California, and Baja California have commonly been identified as Volutoderma averillii (Gabb, 1864). This review of available specimens assigns them to two genera: Volutoderma and Longoconcha Stephenson, 1941.Twelve species, nine of them new, comprise three morphologic lineages of Volutoderma, i.e., 1) “Typical” includes V. querna n. sp., V. averillii (Gabb), V. blakei n. sp., V. jalama n. sp., V. perissa n. sp., and possibly Volutoderma? n. sp.; 2) “Angelica” includes V. angelica n. sp., V. elderi n. sp., and V. ynezae n. sp.; and 3) “Magna” includes V. santana Packard, V. magna Packard, and perhaps V.? antherena n. sp. A new species of Longoconcha, L. eumeka, is the first Pacific Slope record of this genus, which has a Gulf Coast and Tethyan Old World distribution. A smaller volutid, Retipirula Dall, 1907 is endemic to the study area and was formerly known only from its type species R. crassitesta (Gabb, 1869) of Paleocene age. Two new Retipirula are reported: R. calidula of latest Maastrichtian age and R. pinguis of Paleocene age.Only the Volutoderma lineage containing V. averillii has been found north of San Francisco. Recovery of rudist bivalves from formations yielding Volutoderma suggests that these volutes were warm-temperate to subtropical gastropods. Co-occurrences of these gastropods and rudistids may aid in placing the warm-temperate/subtropical boundary during the Late Cretaceous.

Northeast Pacific Upper Cretaceous and Paleocene Glycymeridid Bivalves

2010 ◽  
Vol 84 (5) ◽  
pp. 895-917 ◽  
Author(s):  
Richard L. Squires
Keyword(s):  
Late Cretaceous ◽  
Upper Cretaceous ◽  
New Combination ◽  
Marine Waters ◽  
Shallow Marine ◽  
Fine Grained ◽  
Northeast Pacific ◽  
Siliciclastic Sediments ◽  
First Time ◽  
Warm Temperate

The Late Cretaceous to late Paleocene record of glycymeridid bivalves in the region extending from the Alaska Peninsula, southward to Baja California, Mexico is studied in detail for the first time. Glycymeris pacifica (Anderson, 1902), of late Cenomanian to late Turonian age, is the earliest known glycymeridid in the study area. Very locally, it is found with the middle to late Turonian Glycymeris yoloensis n. sp. The latter apparently represents some intermediate state between genus Glycymeris da Costa, 1778 and genus Glycymerita Finlay and Marwick, 1937. In the study area, Glycymerita is represented by Glycymerita veatchii (Gabb, 1864), middle to late Turonian to late Campanian; Glycymerita banosensis (Anderson, 1958) new combination, late Campanian to latest Maastrichtian; Glycymerita aleuta n. sp., known only from Alaska and of early Maastrichtian age; and Glycymerita major (Stanton, 1896) new combination, Selandian to Thanetian. All the studied species lived in warm-temperate, shallow-marine waters and were shallow burrowers in fine-grained siliciclastic sediments. Variability in morphology is common in sizeable populations of the various species, especially Glycymerita veatchii, which increased nearly fivefold in size during its 19.5 million-year-long range and culminated in shells up to 84 mm in length.

Upper plate deformation during blueschist exhumation, ancestral western California forearc basin, from stratigraphic and structural relationships at Mount Diablo and in the Rio Vista Basin

2021 ◽  
Author(s):  
Jeffrey Unruh
Keyword(s):  
San Francisco ◽  
Late Cretaceous ◽  
Normal Faults ◽  
Coast Range ◽  
Forearc Basin ◽  
Bay Area ◽  
The North ◽  
Early Tertiary ◽  
Local Equivalent ◽  
Structural Relief

ABSTRACT Late Cenozoic growth of the Mount Diablo anticline in the eastern San Francisco Bay area, California, USA, has produced unique 3D exposures of stratigraphic relationships and normal faults that record Late Cretaceous uplift and early Tertiary extension in the ancestral California forearc basin. Several early Tertiary normal faults on the northeast flank of Mount Diablo have been correlated with structures that accommodated Paleogene subsidence of the now-buried Rio Vista basin north of Mount Diablo. Stepwise restoration of deformation at Mount Diablo reveals that the normal faults probably root into the “Mount Diablo fault,” a structure that juxtaposes blueschist-facies rocks of the Franciscan accretionary complex with attenuated remnants of the ophiolitic forearc basement and relatively unmetamorphosed marine forearc sediments. This structure is the local equivalent of the Coast Range fault, which is the regional contact between high-pressure Franciscan rocks and structurally overlying forearc basement in the northern Coast Ranges and Diablo Range, and it is folded about the axis of the Mount Diablo anticline. Apatite fission-track analyses indicate that the Franciscan rocks at Mount Diablo were exhumed and cooled from depths of 20+ km in the subduction zone between ca. 70−50 Ma. Angular unconformities and growth relations in the Cretaceous and Paleogene stratigraphic sections on the northeast side of Mount Diablo, and in the Rio Vista basin to the north, indicate that wholesale uplift, eastward tilting, and extension of the western forearc basin were coeval with blueschist exhumation. Previous workers have interpreted the structural relief associated with this uplift and tilting, as well as the appearance of Franciscan blueschist detritus in Late Cretaceous and early Tertiary forearc strata, as evidence for an “ancestral Mount Diablo high,” an emergent Franciscan highland bordering the forearc basin to the west. This outer-arc high is here interpreted to be the uplifted footwall of Coast Range fault. The stratigraphic and structural relations exposed at Mount Diablo support models for exposure of Franciscan blueschists primarily through syn-subduction extension and attenuation of the overlying forearc crust in the hanging wall of the Coast Range fault, accompanied by (local?) uplift and erosion of the exhumed accretionary prism in the footwall.

Taxonomy and biostratigraphy of Coniacian through Maastrichtian Anchura (Gastropoda: Aporrhaiidae) of the North American Pacific Slope

1996 ◽  
Vol 70 (3) ◽  
pp. 381-399 ◽  
Author(s):  
William P. Elder ◽  
L. R. Saul
Keyword(s):  
New Species ◽  
Late Cretaceous ◽  
North American ◽  
Southern California ◽  
Northern California ◽  
The North ◽  
The Pacific ◽  
Slope Deposits ◽  
Pacific Slope

North American Pacific Slope deposits of Coniacian to Maastrichtian age have yielded eight biostratigraphically useful species of Anchura: A. (Helicaulax?) popenoei new species, Coniacian; A. halberdopsis new species, early Campanian; A. callosa Whiteaves, 1903, early Campanian; A. falciformis (Gabb, 1864), late early to middle Campanian; A. phaba new species, middle to late Campanian; A. ainikta new species, middle to late Campanian; A. gibbera Webster, 1983, late Campanian to early Maastrichtian; A. baptos new species, late Maastrichtian to early Danian. In addition, two other possible species are A. nanaimoensis (Whiteaves, 1879), middle to late Campanian, and Anchura? new species, late Maastrichtian. These species together with two additional Turonian species, A. (Helicaulax) tricosa Saul and Popenoe, 1993, and A. (H.) condoniana Anderson, 1902, allow the definition at least eight Late Cretaceous Anchura zones for the Pacific Slope. These zones have durations of 1.5 m.y. to 4 m.y.Anchura (H.?) popenoei from northern California appears most closely related to A. (Helicaulax) tricosa Saul and Popenoe, 1993, of Turonian age from southern California. Anchura callosa, A. falciformis, A. nanaimoensis, and A. phaba appear to be closely related based on sculptural elements, as does A. gibbera despite having an anterior spur on the wing. However, these species appear to belong to two latitudinally differentiated faunal provinces. Species having a northern range include A. callosa, A. falciformis, and A. nanaimoensis, whereas A. phaba and A. gibbera are from more southern deposits, as are also A. halberdopsis, A. ainikta, and A. baptos.

A new species of Bathynomus A. Milne-Edwards, 1879 (Malacostraca: Peracarida: Isopoda: Cirolanidae) from the upper Miocene of the Guadalquivir Basin (Spain)

Zootaxa ◽  
2020 ◽  
Vol 4819 (1) ◽  
pp. 159-169
Author(s):  
MATÚŠ HYŽNÝ ◽  
ILDEFONSO BAJO CAMPOS ◽  
JOAQUÍN CÁRDENAS CARRETERO
Keyword(s):  
New Species ◽  
East Atlantic ◽  
Environmental Preferences ◽  
Upper Miocene ◽  
North East ◽  
The North ◽  
Geological Past ◽  
The Mediterranean ◽  
Warm Temperate ◽  
A New Species

Today representatives of the giant cirolanid isopods of the genus Bathynomus inhabit tropical to warm-temperate waters of the West Atlantic and the Indo-West Pacific. In not so distant geological past, however, the genus was present also in the Mediterranean, as documented by numerous fossils from the Plio–Pleistocene of Italy. Herein, a somewhat older occurrence of the genus is reported, from the North-East Atlantic. Based on a single posterior moult from the upper Miocene (Tortonian) of southwestern Spain, a new species is described. Bathynomus civisi sp. nov. differs from its congeners by both uropod rami having the obtuse distolateral corner produced as a distinct tip and a wider gap between the second and third side distal spines than between others. The new species is so far known only from the type locality in close vicinity of Arroyo Trujillo, in the municipality of Cantillana (Seville, Spain), where the marls of the Écija Formation are exposed. At the time of deposition of these marls, the area represented a part of the Norbetic Strait, a corridor connecting the North-East Atlantic with the Mediterranean. The new occurrence reported herein further supports the environmental preferences of the genus throughout its geological past for deep-marine settings.

scholarly journals Stratigraphy and palaeontology of the lower Miocene Kiel Sand Member (Berchem Formation) in temporary exposures in Antwerp (northern Belgium)

2020 ◽  
Vol 23 (3-4) ◽  
Author(s):  
STIJN EVERAERT ◽  
DIRK K. MUNSTERMAN ◽  
PIETER J. DE SCHUTTER ◽  
MARK BOSSELAERS ◽  
JEROEN VAN BOECKEL ◽  
...  
Keyword(s):  
Depositional Environment ◽  
Depositional Environments ◽  
Shallow Marine ◽  
Lower Miocene ◽  
North East ◽  
The North ◽  
Stratigraphic Position ◽  
First Time ◽  
The City ◽  
Warm Temperate

The stratigraphic position of the lower Miocene Kiel Sand Member of the Berchem Formation in the Antwerp area (northern Belgium) is not well constrained and its depositional environments are poorly known. Due to a spatial limited decalcification front, the Kiel Sand Member is completely decalcified in southern Antwerp and gradually becomes fossiliferous to the north-east of the city. The stratigraphy and palaeontology of the fossiliferous sediments in three temporary exposures are presented. The dinoflagellate cyst analysis of fossiliferous horizons shows the relative progress of a transgression in the southern North Sea Basin during the early–middle Burdigalian, that probably initiated in the late Aquitanian. The Kiel Sand Member contains an important mollusc fauna, with several species reported for the first time from this member. The taphonomy and fauna of the shell beds indicate a shallow marine, high energetic depositional environment, strongly influenced by storms, currents, waves and a rather low sedimentation rate. The climate was warm-temperate to subtropical. In all studied sections, the Kiel Sand Member could be clearly distinguished from the Antwerpen Sand Member: similarities and differences are discussed. Moving to the north of Antwerp, the erosive base of the Antwerpen Sand Member cuts deeper into the Kiel Sand Member. The Early Miocene Unconformity (EMU) is suggested at this contact.

A new species of Coenothyris (Brachiopoda) from the Triassic (Upper Anisian-Ladinian) of Israel

2002 ◽  
Vol 76 (1) ◽  
pp. 34-42 ◽  
Author(s):  
Howard R. Feldman
Keyword(s):  
New Species ◽  
Middle Triassic ◽  
Shallow Marine ◽  
The North ◽  
Lower Member ◽  
A New Species

Coenothyris oweni new species is described from the Lower Member (Upper Anisian-Ladinian) of the Triassic Saharonim Formation (Upper Anisian–Lower Carnian) at Har Gevanim, Makhtesh Ramon, southern Israel. The Saharonim Formation was deposited under normal, calm, shallow marine conditions as part of the ingression of the Saharonim Sea. The presence of Coenothyris along with characteristic conodonts, ostracodes, foraminiferans, bivalves, cephalopods, gastropods, echinoderms and vertebrate remains is 1) indicative of the Sephardic Province; 2) diagnostic of the Middle Triassic series of Israel; and 3) important in differentiating the Sephardic Province from the Germanic Muschelkalk and Tethyan Realm faunas to the north and correlating the Triassic rocks in the Negev.

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