Nunatak moraines as a repository of what lies beneath the East Antarctic ice sheet
Nunatak moraines as a repository of what lies beneath the East Antarctic ice sheet
复制标题
努纳塔克冰碛是南极东部冰盖下的宝库
DOI：
--
复制
发表时间：
2012
期刊：
影响因子：
--
通讯作者：
S. Hemming
中科院分区：
文献类型：
--
作者：
E. Palmer;K. Licht;R. Swope;S. Hemming
南极伯德冰川顶端孤狼冰原岛峰冰碛物的粒度和物源特征显示了冰下起源的证据，从而提供了东南极冰盖基岩的新信息。隆沃尔夫冰原岛峰冰芯冰碛的粒度数据显示，沿着下游位置的活性侧冰碛（<10%的细砂）中含有更多的粉砂和粘土（>50%的细砂），且25%的卵石有刻面和/或条纹。孤狼冰原岛峰冰碛中的沙子和鹅卵石混合了当地的灯塔超群岩石和外来的长英质火成岩和变质岩。隆沃尔夫冰原岛峰至今的碎屑锆石U/Pb年龄数据显示了重要的锆石年龄群体，包括约1000年的早期罗斯年龄和/或泛非年龄。565-610 Ma，格伦维尔时代（ca. 950-1270 Ma），几个元古代的高峰，和一个突出的晚太古代高峰在约。2700 Ma.碎屑角闪石和云母的40 Ar/ 39 Ar分析也显示罗斯和/或泛非年龄来自约1000年。500至580 Ma，与人口的Grenvilleage hornabellus颗粒约。1150-1250 Ma。这种地质年代学工具的组合可以用来识别回收与初级年龄人口的冰盖侵蚀，从而提供了年龄和分布的未映射，冰覆盖的基岩的限制。我们的数据表明，南极东部冰碛的岩石学和地质年代学特征可用于解决从新生代冰盖历史到前寒武纪基岩地质等地质问题。
The particle size and provenance signature of glacial till from the Lonewolf Nunataks at the head of Byrd Glacier, Antarctica, show evidence of subglacial origin and therefore provide new information about ice-covered bedrock of East Antarctica. Particle-size data from ice-cored moraines at Lonewolf Nunataks show more abundant silt and clay (>50% fi nes) than active lateral moraines along downstream sites (<10% fi nes), and 25% of pebbles are faceted and/or striated. Sand and pebbles from moraines at Lonewolf Nunataks are a mix of locally derived Beacon Supergroup rocks and exotic felsic igneous and metamorphic rocks. The U/Pb detrital zircon data from the Lonewolf Nunataks till show signifi cant populations of zircon ages, including early Ross and/or Pan-African ages of ca. 565–610 Ma, Grenville ages (ca. 950–1270 Ma), several Proterozoic peaks, and one prominent late Archean peak at ca. 2700 Ma. 40 Ar/ 39 Ar analyses of detrital hornblende and mica also show Ross and/or Pan-African ages from ca. 500 to 580 Ma, with a population of Grenvilleage hornblende grains of ca. 1150–1250 Ma. This combination of geochronological tools can be used to identify recycled versus primary age populations eroded by the ice sheet, and so provide constraints on the age and distribution of unmapped, icecovered bedrock. Our data show that petrologic and geochronologic signatures in East Antarctic till can be used to address geologic problems ranging from Cenozoic ice sheet history to Precambrian bedrock geology.
影响因子：
5.3
作者：
Jamieson, Stewart S. R.;Sugden, David E.;Hulton, Nicholas R. J.
通讯作者：
Hulton, Nicholas R. J.