{"title":"中新世Macaronichnus痕迹化石的新浅海高纬度记录,重新加工的三角洲前斜形,Punta Basílica,火地岛,阿根廷","authors":"E. Olivero, M. L. López Cabrera","doi":"10.1080/10420940.2020.1755854","DOIUrl":null,"url":null,"abstract":"Abstract A new high-latitude record of the trace fossil Macaronichnus segregatis degiberti is documented from the lower Miocene Punta Basílica beds, Tierra del Fuego, which were previously considered to be deep-marine channel and levee deposits. Based on a combined ichnological and sedimentological study, however, these beds are herein re-interpreted as shallow-marine, delta-front clinoform deposits. Macaronichnus-bearing beds in the stratigraphically older clinoforms are characterized by: (1) sandstones with wave ripples and wave-ripple cross-lamination; (2) cross-stratified sandstones forming large compound dunes and tidal bars; and (3) intervening heterolithic mudstone-sandstone couplets with current and wave ripples. The sedimentary facies preserving M. s. degiberti were deposited during the onset of transgression, indicated by wave and tide reworking of underlying steeply dipping, delta-front clinoforms deposits. The master bedding surfaces of compound tidal bars are characterized by a dense, monospecific fabric of M. s. degiberti. Compared with other Macaronichnus ichnofabrics, reported elsewhere as characterizing short colonization windows on foresets of tidal dunes or bars, the Punta Basílica ichnofabric represents a longer colonization window, associated with episodic reworking and redeposition of loose, nutrient-rich sand grains just above the master bedding surfaces. The record of M. s. degiberti in Tierra del Fuego supports the previous interpretations that restrain its producer to high-latitude, shallow-marine cold waters.","PeriodicalId":51057,"journal":{"name":"Ichnos-An International Journal for Plant and Animal Traces","volume":null,"pages":null},"PeriodicalIF":0.8000,"publicationDate":"2020-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"2","resultStr":"{\"title\":\"A new shallow-marine, high-latitude record of the trace fossil Macaronichnus in Miocene, reworked delta-front clinoforms, Punta Basílica, Tierra Del Fuego, Argentina\",\"authors\":\"E. Olivero, M. L. López Cabrera\",\"doi\":\"10.1080/10420940.2020.1755854\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"Abstract A new high-latitude record of the trace fossil Macaronichnus segregatis degiberti is documented from the lower Miocene Punta Basílica beds, Tierra del Fuego, which were previously considered to be deep-marine channel and levee deposits. Based on a combined ichnological and sedimentological study, however, these beds are herein re-interpreted as shallow-marine, delta-front clinoform deposits. Macaronichnus-bearing beds in the stratigraphically older clinoforms are characterized by: (1) sandstones with wave ripples and wave-ripple cross-lamination; (2) cross-stratified sandstones forming large compound dunes and tidal bars; and (3) intervening heterolithic mudstone-sandstone couplets with current and wave ripples. The sedimentary facies preserving M. s. degiberti were deposited during the onset of transgression, indicated by wave and tide reworking of underlying steeply dipping, delta-front clinoforms deposits. The master bedding surfaces of compound tidal bars are characterized by a dense, monospecific fabric of M. s. degiberti. Compared with other Macaronichnus ichnofabrics, reported elsewhere as characterizing short colonization windows on foresets of tidal dunes or bars, the Punta Basílica ichnofabric represents a longer colonization window, associated with episodic reworking and redeposition of loose, nutrient-rich sand grains just above the master bedding surfaces. The record of M. s. degiberti in Tierra del Fuego supports the previous interpretations that restrain its producer to high-latitude, shallow-marine cold waters.\",\"PeriodicalId\":51057,\"journal\":{\"name\":\"Ichnos-An International Journal for Plant and Animal Traces\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":0.8000,\"publicationDate\":\"2020-04-24\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"2\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Ichnos-An International Journal for Plant and Animal Traces\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://doi.org/10.1080/10420940.2020.1755854\",\"RegionNum\":4,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q4\",\"JCRName\":\"PALEONTOLOGY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Ichnos-An International Journal for Plant and Animal Traces","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.1080/10420940.2020.1755854","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"PALEONTOLOGY","Score":null,"Total":0}
A new shallow-marine, high-latitude record of the trace fossil Macaronichnus in Miocene, reworked delta-front clinoforms, Punta Basílica, Tierra Del Fuego, Argentina
Abstract A new high-latitude record of the trace fossil Macaronichnus segregatis degiberti is documented from the lower Miocene Punta Basílica beds, Tierra del Fuego, which were previously considered to be deep-marine channel and levee deposits. Based on a combined ichnological and sedimentological study, however, these beds are herein re-interpreted as shallow-marine, delta-front clinoform deposits. Macaronichnus-bearing beds in the stratigraphically older clinoforms are characterized by: (1) sandstones with wave ripples and wave-ripple cross-lamination; (2) cross-stratified sandstones forming large compound dunes and tidal bars; and (3) intervening heterolithic mudstone-sandstone couplets with current and wave ripples. The sedimentary facies preserving M. s. degiberti were deposited during the onset of transgression, indicated by wave and tide reworking of underlying steeply dipping, delta-front clinoforms deposits. The master bedding surfaces of compound tidal bars are characterized by a dense, monospecific fabric of M. s. degiberti. Compared with other Macaronichnus ichnofabrics, reported elsewhere as characterizing short colonization windows on foresets of tidal dunes or bars, the Punta Basílica ichnofabric represents a longer colonization window, associated with episodic reworking and redeposition of loose, nutrient-rich sand grains just above the master bedding surfaces. The record of M. s. degiberti in Tierra del Fuego supports the previous interpretations that restrain its producer to high-latitude, shallow-marine cold waters.
期刊介绍:
The foremost aim of Ichnos is to promote excellence in ichnologic research. Primary emphases center upon the ethologic and ecologic significance of tracemaking organisms; organism-substrate interrelationships; and the role of biogenic processes in environmental reconstruction, sediment dynamics, sequence or event stratigraphy, biogeochemistry, and sedimentary diagenesis. Each contribution rests upon a firm taxonomic foundation, although papers dealing solely with systematics and nomenclature may have less priority than those dealing with conceptual and interpretive aspects of ichnology. Contributions from biologists and geologists are equally welcome.
The format for Ichnos is designed to accommodate several types of manuscripts, including Research Articles (comprehensive articles dealing with original, fundamental research in ichnology), and Short Communications (short, succinct papers treating certain aspects of the history of ichnology, book reviews, news and notes, or invited comments dealing with current or contentious issues). The large page size and two-column format lend flexibility to the design of tables and illustrations. Thorough but timely reviews and rapid publication of manuscripts are integral parts of the process.