Stratigraphy and architecture of the Upper Triassic Ischigualasto Formation, Ischigualasto Provincial Park, San Juan, Argentina

2009 ◽  
Vol 27 (1) ◽  
pp. 74-87 ◽  
Author(s):  
Brian S. Currie ◽  
Carina E. Colombi ◽  
Neil J. Tabor ◽  
Todd C. Shipman ◽  
Isabel P. Montañez
Keyword(s):  
Upper Triassic ◽  
San Juan ◽  
Provincial Park

Systematics and taphonomy of fossil woods from a new locality in the Upper Triassic Carrizal Formation of the El Gigantillo area (Marayes-El Carrizal Basin), San Juan, Argentina

2019 ◽  
Vol 90 ◽  
pp. 94-106 ◽  
Author(s):  
Gustavo Correa ◽  
Josefina Bodnar ◽  
Carina Colombi ◽  
Paula Santi Malnis ◽  
Angel Praderio ◽  
...  
Keyword(s):  
Upper Triassic ◽  
San Juan

Fission-track dating of the tectonic development of the San Juan Islands, Washington

1986 ◽  
Vol 23 (9) ◽  
pp. 1318-1330 ◽  
Author(s):  
Samuel Y. Johnson ◽  
Robert A. Zimmermann ◽  
Charles W. Naeser ◽  
John T. Whetten
Keyword(s):  
Late Cretaceous ◽  
Lower Cretaceous ◽  
Fission Track ◽  
Frictional Heating ◽  
Geothermal Gradient ◽  
Upper Triassic ◽  
Detrital Zircons ◽  
San Juan ◽  
San Juan Islands ◽  
Zircon Fission Track

The San Juan Islands of Washington State form a geologically complex province located between the north Cascades, Vancouver Island, and the Olympic Peninsula. We have obtained 53 fission-track dates from the San Juan Islands province that help constrain its late Paleozoic to early Cenozoic tectonic and sedimentary history and its relationship to neighboring geologic terranes. The San Juan Islands can be divided into two main blocks separated by the Haro fault. South of the Haro fault, complexly deformed, metamorphosed, and probably exotic early Paleozoic to early Late Cretaceous rocks form four imbricate thrust plates separated by south- and east-dipping late Early to Late Cretaceous thrust faults. Reset zircon fission-track dates indicate that thrusting may have produced an upside-down geothermal gradient in the uppermost plate, the Decatur terrane. If present, this gradient was probably produced by conductive or frictional heating associated with a now-eroded overlying thrust fault and hot thrust plate. Cretaceous thrusting in the southern San Juan Islands was accompanied by uplift and resetting of apatite fission-track dates. In contrast to correlative rocks of the southern San Juan Islands, Upper Triassic to Lower Cretaceous rocks in and north of the Haro fault zone are essentially unmetamorphosed and only broadly folded. Apatite dates from the Upper Triassic Haro Formation and the Upper Jurassic and Lower Cretaceous Spieden Group indicate they did not participate in Late Cretaceous uplift of the southern San Juan Islands. Together with their basement (the Wrangellia terrane?), these rocks probably acted as a backstop to thrusting. The synorogenic Late Cretaceous Nanaimo basin formed north of the Haro fault in front of the advancing San Juan Islands thrust system. The age of Nanaimo deposition matches uplift (apatite) dates in the southern San Juan Islands, and detrital zircons from the Nanaimo Group yield dates consistent with southern San Juan Islands sources. Burial led to resetting of apatite dates in what is probably the deeper part of the Nanaimo basin.

FIRST ARGENTINE MICROFOSSIL BONEBED FROM THE UPPER TRIASSIC MARAYES—EL CARRIZAL BASIN, SAN JUAN PROVINCE

Palaios ◽  
2015 ◽  
Vol 30 (10) ◽  
pp. 743-757 ◽  
Author(s):  
CARINA E. COLOMBI ◽  
RICARDO N. MARTÍNEZ ◽  
GUSTAVO CORREA ◽  
ELIANA FERNáNDEZ ◽  
PAULA SANTI MALNIS ◽  
...  
Keyword(s):  
Upper Triassic ◽  
San Juan ◽  
Fluvial System ◽  
High Concentration ◽  
Fine Grained ◽  
Subaerial Exposure ◽  
Low Degree ◽  
Authigenic Mineral ◽  
Three Stages ◽  
Tooth Marks

Abstract The first Triassic microfossil bonebed found in Argentina is located 80 meters from the top of the Quebrada del Barro Formation in the Marayes-El Carrizal Basin, in the province of San Juan. It consists of specimens from at least 63 individuals from an anomalously high concentration of fossils distributed laterally and vertically in a meter-thick fine-grained deposit. Two new taxa from the genera Sphenodontia and Eucynodontia had previously not been found in Argentine Triassic quarries. The bonebed is preserved in a mudflow deposit interbedded with calcic-Argillisols in the medial-distal zone of a distributary fluvial system (DFS). The accumulation is characterized by small-sized skeletal fragments (skulls, jaws and vertebra; all less than 50 mm), low degree of articulation, variable degrees of subaerial exposure, tooth marks, surface dissolution, and an alkaline authigenic mineral suite. Detailed paleoenvironmental and taphonomic characterization indicate that this accumulation underwent three stages in its taphonomic history: (1) biogenic extrinsic concentration; (2) local transportation and re-deposition by a mudflow on a swampy floodplain; and (3) drying and pedogenesis. Additionally, the deposit highlights biogenic activity as a way to concentrate a paleofaunal assemblage that likely represents the original community, and mudflow deposits from crevasse splays in DFS as a potential facies for microfossil preservation.

scholarly journals Ant species (Hymenoptera: Formicidae) in the three forests of the Ischigualasto Provincial Park, a protected area of the Monte Desert, Argentina

2018 ◽  
Vol 19 (3) ◽  
pp. 831-839 ◽  
Author(s):  
EMILCE AMATTA ◽  
LUIS A. CALCATERRA ◽  
STELLA . M GIANNONI
Keyword(s):  
Protected Area ◽  
Animal Species ◽  
Sampling Methods ◽  
New Records ◽  
San Juan ◽  
Monte Desert ◽  
Desert Areas ◽  
Arid Desert ◽  
Ant Diversity ◽  
Provincial Park

Amatta E, Calcaterra LA, Giannoni SM. 2018. Ant species (Hymenoptera: Formicidae) in the three forests of the Ischigualasto Provincial Park, a protected area of the Monte Desert, Argentina. Biodiversitas 19: 831-839. Deforestation and overgrazing mediated by the humans have caused a serious process of desertification in the Argentine Monte Desert, which threats biodiversity of this ecosystem. Forests provide important resources and refuge for animal species, such as ants. The objective of this work was to survey the ant fauna of dryland forests of Ischigualasto Provincial Park, a protected area located in the hyper-arid Monte Desert ecoregion in the province of San Juan, Argentina. Ant species were surveyed in summer in three types of forests (Prosopis, Ramorinoa and Bulnesia forests), using a combination of sampling methods: pitfall-traps, baiting, and hand collection. A total of 33 ant species were collected, of which 17 are new records for the Monte Desert and Dry Chaco and 24 for the San Juan province. The species richness is within the range reported for other Argentine desert and semi-desert areas. Prosopis forest was the richest with 32 species (24 exclusive), followed by Ramorinoa and Bulnesia forests with 11 and 4 species, respectively. This study contributes to improve the knowledge of ant fauna in desert habitats of the world, especially those inhabiting Prosopis forests, which are the most important ant diversity hotspots within the hyper-arid desert.

A new species of Rhinella (Anura: Bufonidae) from Ischigualasto Provincial Park, San Juan, Argentina

Zootaxa ◽  
2010 ◽  
Vol 2396 (1) ◽  
pp. 50 ◽  
Author(s):  
EDUARDO SANABRIA ◽  
LORENA QUIROGA ◽  
FEDERICO ARIAS ◽  
RICARDO CORTEZ
Keyword(s):  
New Species ◽  
Natural History ◽  
Geographic Distribution ◽  
Related Species ◽  
Vertebral Column ◽  
High Elevation ◽  
San Juan ◽  
Closely Related Species ◽  
Provincial Park ◽  
A New Species

A new species of bufonid frog, Rhinella bernardoi sp. nov., belonging to the granulosa group, is described from moderately high elevation (1400 m) at Ischigualasto Provincial Park, San Juan, Argentina. The morphology of the new species is compared to and diagnosed from other closely related species of the same group (R. bergi, R. fernandezae, and R. granulosa). We also describe the osteology of the skull and the vertebral column of the new species and present data on its geographic distribution and natural history.

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