{"title":"Uranium and strontium isotope study of late-stage speleothems from lava tube caves in El Malpais National Monument, New Mexico","authors":"Zachary LaPointe, V. Polyak, Y. Asmerom","doi":"10.56577/ffc-64.223","DOIUrl":"https://doi.org/10.56577/ffc-64.223","url":null,"abstract":"—Strontium isotope values measured for six calcite and opal speleothem samples from five lava tube caves, formed in three different >15,000 year-old basalt flows in El Malpais National Monument, western New Mexico, reveal a combined soil- and bedrock-related origin. All speleothem growth was several thousand years after the lava tube caves formed. Uranium-series ages of all six samples shows that speleothem growth likely coincided with wetter periods of the Holocene. Four of the six samples formed during the late Holocene between 4,000 and 1,000 years ago, consistent with previous recon- structions of a wetter Late Holocene in the southwestern United States. Growth of a middle Holocene sample is coincident with a brief wetter period in northern Mexico and central New Mexico defined by lacustrine sediment studies, and growth of an early Holocene sample crudely matches a wetter period defined by Carlsbad area stalagmite growth.","PeriodicalId":367315,"journal":{"name":"Geology of Route 66 Region: Flagstaff to Grants","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132097949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The Water Canyon/Timber Canyon fan complex on the southeast flank of Mount Taylor, New Mexico","authors":"P. Drakos, J. Riesterer","doi":"10.56577/ffc-64.175","DOIUrl":"https://doi.org/10.56577/ffc-64.175","url":null,"abstract":"—the Water–timber Canyon fan complex is an example of a highly dissected fan comprising predominantly early to middle Pleistocene fan deposits on the piedmont southeast of Mt. taylor. Deposition of the oldest, early Pleistocene fan unit (Qf0) records breaching of the Mt. Taylor amphitheater by erosion into the volcanic edifice. Deposition of multiple inset fan deposits (Qf1 through Qf3) was in response to episodic pulses of sediment, combined with regional incision, from early through middle Pleistocene time. Eruption of the 0.38 to 0.128 Ma Laguna basalt, which flowed along the Rio San Jose drainage, created a stable base level south of the Water–timber Canyon fan complex and has resulted in piedmont aggradation or minimal incision into middle Pleistocene Qf3 surfaces. Holocene fan deposits (Qf4) have prograded over Qf3 surfaces in proximal fan areas or are inset against Qf3 in some distal fan areas.","PeriodicalId":367315,"journal":{"name":"Geology of Route 66 Region: Flagstaff to Grants","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129821110","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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