干旱区生态环境知识资源中心(Arid): Resurfaced paleodunes from the Botucatu erg amid Cretaceous Paran volcanics

Arid

DOI	10.1016/j.geomorph.2021.107702
	Resurfaced paleodunes from the Botucatu erg amid Cretaceous Paran volcanics
	Hartmann, Leo Afraneo; Cerva-Alves, Tiara
通讯作者	Hartmann, LA (corresponding author), Univ Fed Rio Grande do Sul, Inst Geociencias, Ave Bento Goncalves 9500, BR-91501970 Porto Alegre, RS, Brazil.
来源期刊	GEOMORPHOLOGY
ISSN	0169-555X
EISSN	1872-695X
出版年	2021
卷号	383
英文摘要	Extensive exposure of Cretaceous paleodunes partly covered by basaltic rocks is a rare surficial structure in the geomorphology of continents. The Parana Basin offers the opportunity in southernmost Brazil to study the rela-tionships between the major Botucatu paleoerg-turned into the Guarani Aquifer (1.2 million km(2)) and the over-lying, first flows from the Parana Volcanic Province (1 million km(2)). We describe the Inhandui Paleodune Field (IPDF; 15,000 km(2)) preserved by the first two (up to six) flows of the Parana Volcanic Province. The field was exposed by erosion of volcanic overburden in Fronteira Oeste of southernmost Brazil. A plan view of the field is examined in the extensive grasslands and rice crops of the pampas. Observational geology from satellite images was followed by field description, gammaspectrometry, petrography and whole-rock geochemistry. Results show that bedforms include thousands of varied individual and compound paleodunes, including crescentic (barchane), linear, circle (blowout), and complex forms. Cerro do Jarau was considered an impact crater, and is here characterized as a compound paleodune. The paleoerg sand was silicified and deformed by hot water from the Guarani aquifer and the explosion of vapor in IPDF. The active dunes were flooded with tholeiitic lavas; heating by residual heat from volcanism (raised geothermal gradient) led to sand injection into overlying volcanic rocks. Silicification accompanied and followed the injection process. The Botucatu Formation includes the paleodunes and was the source bed of the sand injectites (Novo Hamburgo Complex) into the overlying volcanic group. We thus uncovered the processes associated with the flooding of a major, active erg by lavas from a large volcanic province. Hyperdry climate prevailed in the sandy Botucatu desert and continued in the rocky Serra Geral desert. The studied geological relationships are unique in the geological records; their understanding fosters the correct description of geological evolution of other terrains where some of the parameters are present. (C) 2021 Elsevier B.V. All rights reserved.
英文关键词	Inhandui Paleodune Field Parana Volcanic Province Botucatu Formation Guarani Paleoaquifer Hydrothermal silicification Jarau paleodune
类型	Article
语种	英语
收录类别	SCI-E
WOS记录号	WOS:000640909900002
WOS关键词	PHREATIC ERUPTIONS ; SOUTH GREENLAND ; GARDAR PROVINCE ; AQUIFER SYSTEM ; AEOLIAN DUNES ; NORTE BASIN ; LAVA FLOWS ; BRAZIL ; STRATIGRAPHY ; DEFORMATION
WOS类目	Geography, Physical ; Geosciences, Multidisciplinary
WOS研究方向	Physical Geography ; Geology
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/350415
作者单位	[Hartmann, Leo Afraneo; Cerva-Alves, Tiara] Univ Fed Rio Grande do Sul, Inst Geociencias, Ave Bento Goncalves 9500, BR-91501970 Porto Alegre, RS, Brazil
推荐引用方式 GB/T 7714	Hartmann, Leo Afraneo,Cerva-Alves, Tiara. Resurfaced paleodunes from the Botucatu erg amid Cretaceous Paran volcanics[J],2021,383.
APA	Hartmann, Leo Afraneo,&Cerva-Alves, Tiara.(2021).Resurfaced paleodunes from the Botucatu erg amid Cretaceous Paran volcanics.GEOMORPHOLOGY,383.
MLA	Hartmann, Leo Afraneo,et al."Resurfaced paleodunes from the Botucatu erg amid Cretaceous Paran volcanics".GEOMORPHOLOGY 383(2021).