Geo- and thermochronology data for detrital minerals from Transantarctic Mountains till

Detrital minerals were isolated from glacial till samples from the heads of six outlet glaciers in the Transantarctic Mountains, the mouth of Scott Glacier, and beneath three West Antarctic ice streams to determine if East and West Antarctic sediment sources have distinct geochronologic tracers. Grains from the ubiquitous zircon U-Pb age population spanning the Ross/Pan-African Orogeny (480-545 Ma) were also dated by (U-Th)/He analysis (ZHe). ZHe ages on grains from East Antarctic tills can be subdivided into two populations of 115-180 Ma and 210-600 Ma. Grains in East Antarctic tills with a ZHe age of 115-180 Ma were recycled into the Beacon Supergroup and the ages reflect cooling within the Beacon basin during the Jurassic and Cretaceous. ZHe ages of three Beacon Supergroup sandstone clasts collected from moraines, and in situ sandstones at Shackleton Glacier all yielded ZHe ages between 110-180 Ma. Additional hornblende 40Ar/39Ar, apatite U-Pb and (U-Th)/He ages from sites in the north central Transantarctic Mountains record the time from the Ross/Pan-African orogeny through the latest Cretaceous, indicating cooling of the Granite Harbour Intrusives and exhumation to form the Kukri Peneplain. Detritus from West Antarctic tills also have a 115-200 Ma ZHe population and an older population with ages between 200 and 350 Ma and are presumed to reflect cooling signatures from sources in East Antarctica and Marie Byrd Land.

本研究从横贯南极山脉（Transantarctic Mountains）6条出口冰川源头、斯科特冰川（Scott Glacier）河口以及3条西南极冰流下方采集的冰碛物样品中分离碎屑矿物，旨在探究东南极与西南极沉积物源是否具备独特的地质年代学示踪指标。针对遍布罗斯/泛非造山带（Ross/Pan-African Orogeny，480~545 Ma）的锆石U-Pb年龄群颗粒，同步开展了（U-Th）/He热年代学分析（以下简称ZHe）。东南极冰碛物中的锆石ZHe年龄可划分为115~180 Ma与210~600 Ma两个年龄群体。其中ZHe年龄介于115~180 Ma的东南极冰碛物锆石颗粒，曾被再循环至比肯超群（Beacon Supergroup）中，其年龄值反映了侏罗纪至白垩纪时期比肯盆地内的冷却过程。从冰碛垄采集的3块比肯超群砂岩岩屑，以及沙克尔顿冰川（Shackleton Glacier）的原位砂岩样品，其锆石ZHe年龄均介于110~180 Ma之间。横贯南极山脉中北部地区的额外角闪石⁴⁰Ar/³⁹Ar、磷灰石U-Pb以及（U-Th）/He年龄数据，记录了从罗斯/泛非造山带至晚白垩世的演化时序，指示了格兰德港侵入体（Granite Harbour Intrusives）的冷却作用及剥露形成库克里准平原（Kukri Peneplain）的过程。西南极冰碛物的碎屑锆石同样存在115~200 Ma的ZHe年龄群，以及200~350 Ma的古老年龄群，推测其分别对应东南极与玛丽·伯德地（Marie Byrd Land）物源区的冷却信号。