Tectonic, magmatic and hydrothermal evolution of ocean floor spreading at Macquarie Island

Macquarie Island offers a rare land-based cross-section through the deep ocean floor, which covers 60% of our Earth. It formed 11 million years ago as slow spreading crust, which has had minimal study compared to more common fastspreading crust. Does the difference in spreading speed produce different crustal geometry, composition, hydrothermal fluids, and cycling of sulfur between ocean and crust? To gain insights to these and related questions, we propose to study uplifted and eroded sections through a series of fault zones, spaced along the length of Macquarie Island, which were the last magmatic, structural and hydrothermal events to occur before shifting stresses drove the seafloor up to form the Macquarie Ridge mountain chain. This dataset is a summary of samples obtained by Mr Steve Lewis for the purposes of investigating hydrothermal alteration in oceanic crust on Macquarie Island. Samples derive from the major lake, Lusitania Bay, and Caroline Cove areas. Each sample consists of rock chips up to a maximum of 1 kg.Samples were all obtained by hand with a geological hammer.The fields in this dataset are:SampleEasting NorthingDateLocationTransectDetails

麦夸里岛（Macquarie Island）是罕见的陆上天然剖面，可直接观测覆盖地球表面积60%的深海洋壳。该岛形成于1100万年前，属于慢速扩张洋壳（slow spreading crust），相较于更为普遍的快速扩张洋壳（fastspreading crust），其研究程度极低。扩张速率的差异是否会导致洋壳的几何形态、组分、热液流体（hydrothermal fluids）以及洋壳与海洋间的硫循环产生差异？为解答此类及相关科学问题，我们计划沿麦夸里岛全长布设一系列断裂带，对其中抬升并受侵蚀的洋壳剖面展开研究——这些剖面记录了构造应力转变驱动洋底抬升形成麦夸里岭山脉链之前的最后一次岩浆、构造与热液活动。本数据集为史蒂夫·刘易斯（Steve Lewis）先生为研究麦夸里岛洋壳热液蚀变（hydrothermal alteration）所采集样品的汇总。样品采自卢西塔尼亚湾（Lusitania Bay）与卡罗琳湾（Caroline Cove）的主要区域。每件样品为最大重量不超过1千克的岩石碎屑，全部通过地质锤手工采集。本数据集包含以下字段：采样东坐标、采样北坐标、采集日期、采样点位、断面信息、详细说明。