Haizhu Stone - 海珠石 EarthCache

Introduction

Haizhu Stone(海珠石) is a huge reef in the Pearl River in Guangzhou. It is made of red gravel and is more than 100 metres long and about 50 metres wide. It is named after its rounded shape like a pearl because it has been washed by the river for a long time and appears and disappears on the river with the tide.

The stone is also known as the Three Stones of Guangzhou, together with Fuqiu Stone(浮丘石) and Haiyin Stone(海印石). Fuqiu Stone, located in the eastern section of Zhongshan Qi Road, was a red conglomerate mound in the Pearl River to the west of Guangzhou, and was named after its shape; Haiyin Stone, located at the intersection of Guangjiu Damalu and Guangjiu Sanmalu, was also a giant reef in the Pearl River in Guangzhou in ancient times, which was made up of red sandstone and sand conglomerate, and resembled a seal. Along the river at Oi Kwan Hotel(爱群大酒店) on West Yanjiang Road, it has been joined to the land.

Haizhu Stone has been a symbol of Guangzhou for centuries, and Haizhu District was named after it (although Haizhu Stone was not located in Haizhu District). The names of places within the current cultural core of Beijing Road, Yingzhu Street(迎珠街), Lianzhu Street(连珠街), Haizhu Square(海珠广场), Haizhu Bridge(海珠桥) and Haizhu Road(海珠路) are also derived from the Haizhu Stone. In addition, the International Centre for Asteroids (ICA), in its Bulletin No. 75550 of 2011, announced that asteroid 273836 was officially named "Hoijyusek" (the Cantonese transcription of "Haizhu Stone").

History

During the Song Dynasty, Haizhu Stone was still in the river, but later, due to sediment alluvium, it was connected to the land on the northern bank of the Pearl River and became a tourist attraction for many dynasties. Cidu Temple(慈度寺) was built on Haizhu Stone in Song Dynasty, and during Tongzhi Emperor period in Qing Dynasty, a fortress was built on the site.

In 1928, Haizhu Park was built on Haizhu Stone. And in 1931, when the new embankment was built (today's West Yanjiang Road), the government funded the destruction of the Haizhu Stone with dynamites, and the Haizhu Park was filled in to form a flat area with the north bank, on which roads and buildings were built. Since the most prosperous area along the river was the most expensive, the narrow river branch between Haizhu Stone and the river bank was filled in, and the section of the long embankment that curved into it was straightened out and a new embankment was built from the Oi Kwan Mansion(爱群大厦) to the Tianzi Pier(天字码头).

In 2000, during the renovation of the sewerage pipes on West Yanjiang Road, the remnants of the roots of the bombed-out Haizhu Stone were accidentally discovered. The government had planned to protect the exposed part and to recreate Haizhu Stone by paving a tourist path with transparent tempered glass on top of the site. However, the plan did not materialise, and the site was converted into a high-rise residential development, Canton View Bay, with part of the stone being crushed underneath the high-rise building and the remaining part being buried on the West Yanjiang Road. The Government later adopted a compromise approach by excavating the remaining stones from the ground and placing them in the vicinity of the original Haizhu Stone. In this way, the heritage was protected and a new attraction was added to Yanjiang Road.

Geological Time

Geological time is a unit of time used to describe events in the history of the Earth, usually in geology and archaeology. The geological time scale (GTS) is a scale that divides important geological events in the Earth's history into a number of stages.

Geological time is divided into six units of time. Listed from the largest to the smallest, they are Eon, Era, Period, Epoch, Age and Chron.

The entire geological chronology can be divided into 4 Eons according to the Eon scale.

• the Hadean Eon: the period when the phenomenon of life began
• the Archean Eon: the period of the first organisms
• the Proterozoic Eon: the emergence of multicellular organisms as individuals visible to the naked eye
• the Phanerozoic Eon: the period when modern life existed

The Precambrian is the unofficial collective name for the geological time before the Phanerozoic Eon, originally formally known as the Cryptozoic Eon, but later split into three Eons: the Hadean Eon, the Archaean Eon and the Proterozoic Eon. It began about 4.5 billion years ago during the formation of the Earth and ended about 542 million years ago with the birth of a large number of crustaceans visible to the naked eye.

Although the Precambrian period accounts for about seven eighths of the Earth's history, it is rather poorly understood. This is because there are few fossil records from the Precambrian and most of them, such as stromatolites, are only suitable for biostratigraphic studies. In addition, many Precambrian rocks have been severely metamorphosed, rendering their origin obscure. Others have either eroded and destroyed or are still buried beneath the strata of the Phanerozoic Eon.

Around 4.5 billion years ago, the primordial Earth was assembled from material orbiting the Sun. Soon afterwards, the Moon was separated, probably by the impact of an asteroid (the size of Mars) (see the Great Collision theory). The Earth's surface was initially covered with magma, and a solid crust emerged around 4.4 billion years ago. The oldest known rock was found in western Australia, and radiometric analysis shows that this zircon crystallisation is about 4.44 billion years old.

The fossil record is relatively extensive and better researched for the Phanerozoic Eon, where modern organisms began to exist. Within the Phanerozoic Eon, there are three Eras, and the three Eras are divided into 12 Periods:

• the Paleozoic Era: the period of ancient life
  • the Cambrian Period: Named for Cambria, a latinised form of the Welsh name for Wales, Cymru.
  • the Ordovician Period: Named after the Celtic tribe, Ordovices.
  • the Silurian Period: Named after the Celtic tribe, the Silures.
  • the Devonian Period: Named after Devon, England.
  • the Carboniferous Period: Means 'coal-bearing', from the Latin carbō (coal) and ferō (to bear, carry).
  • the Permian Period: Named after the historical region of Perm, Russian Empire.
• the Mesozoic Era: a period of moderately evolved organisms
  • the Triassic Period: From the Trias of Friedrich August von Alberti in reference to a trio of formations widespread in southern Germany.
  • the Jurassic Period: Named after the Jura Mountains. 
  • the Cretaceous Period: Derived from Terrain Crétacé used in 1822 by Jean d'Omalius d'Halloy in reference to extensive beds of chalk within the Paris Basin. Ultimately derived from the Latin crēta meaning (chalk).
• the Cenozoic Era: the period of modern life
  • the Neogene Period: Derived from the Greek words νέος (néos) meaning 'new', and γενεά (geneá) meaining 'genesis' or 'birth'.
  • the Paleogene Period: Derived from the Greek words παλιός (palaiós) meaning 'old', and γενεά (geneá) meaining 'genesis' or 'birth'.
  • the Quaternary Period

The Cenozoic Era was originally divided into four Periods: the Primary Period, the Secondary Period, the Tertiary Period and the Quaternary Period. The Quaternary Period is the period of human existence; the Tertiary Period is the period of the emergence of mammals; the Secondary Period is the epoch of reptiles, and the Primary Period includes the period before the emergence of reptiles. Later the Primary Period and the Secondary Period were dropped in the 19th century. The Tertiary was also later withdrawn and divided into the Palaeocene Period and the Neocene Period.

Earthcache

To log this Earthcache, please complete the following questions and tasks and send me a message (no need to wait for my reply).

1. Please look for the scattered parts of Haizhu Stone along Yanjiang Road and read the introduction signs nearby. According to the signs, in which "Period" was Haizhu Stone formed (you can search on the Internet in case the signs are removed)?
2. According to the "Period" you answer in Question 1, to which "Eon" and which "Era" does that "Period" belong?
3. Upload a photo in the log with the word "海珠石" along West Yanjiang Road or near the GZ and include your Trackables or Handheld GPS or Geocaching Apps or anything that identifies you as a Geocacher.

简介

海珠石指古时广州珠江中的一块巨型礁石，又名海珠岛、走珠石和海珠洲。由红色砂砾岩构成，长 100 多米，宽约 50 米，因长期被江水冲刷而浑圆如珠，随潮汐变化浮沉海上（广州人称较宽的江河为“海”）而得名。

海珠石与浮丘石、海印石并称为羊城三石。其中浮丘石位于今中山七路的东段，是古时广州城西珠江中浮露出水面的一个红色砾岩小丘，并按其形状取名为浮丘石；海印石位于今广九大马路与广九三马路相交处，也是古时广州珠江中的一块巨型礁石，它是由红色砂岩和砂砾岩构成的海蚀平台地貌，形似印章而得名海印石；而海珠石在今沿江西路爱群大酒店江边，已与陆地连成一片。

海珠石在数个世纪以来一直被当作广州的象征之一，海珠区即得名于海珠石（尽管海珠石并不位于海珠区）。现今北京路文化核心区范围内，迎珠街、连珠街、海珠广场、海珠桥、海珠路等地名也均来源于海珠石。除此以外，国际小行星中心也在 2011 年发布的第 75550 号公报中，宣布第 273836 号小行星正式命名为 Hoijyusek（即“海珠石”的粤拼转写）。

历史

宋朝时海珠石仍在江中，后由于泥沙冲积，海珠石与珠江北岸陆地相连，成为了历代的游览胜地。宋代时石上建有慈度寺，清朝同治时曾在此建炮台。

1928 年在此建成海珠公园。1931 年，当时因为修筑新堤（即今天的沿江西路），政府出资炸毁了海珠石，并将海珠公园填为平地与北岸连成一片，在上面修路建楼宇。因沿河最繁华地区地价最高，又把海珠石和河岸相隔的狭窄汊道填平，把长堤弯入的一段拉直，筑新堤由爱群大厦直到天字码头，于是海珠岛的南缘变成了新堤的一段，并在新填地段建起了十五层的爱群大厦等建筑。

2000 年，在沿江西路排污管道改造工程中，意外发现了海珠石巨礁被炸后的残余石根。市政府曾规划将显露部分保护起来，在海珠石的遗址上面用透明钢化玻璃铺砌观光道，重现海珠石风采。不过计划最终并没有实现，该处被发展商改建为高层的住宅楼盘“爱群荟景湾”，海珠石的一部分就是高楼大厦压在底下，而剩余部分则被继续掩埋在沿江西路上。后来，政府采取了一个折衷的办法，把残留于地下的海珠石挖出来，分散摆放在原海珠石附近。如此既保护了文物，又为沿江路增加了一处新景点。

地质年代

地质年代（geological age），又称地质时期、地质时间、地史时期，是用来描述地球历史事件的时间单位，通常在地质学、考古学中使用。依地球历史发生的重要地质事件作分界，将其划为若干阶段而制作的标度，称作地质年代表或地质年表（geologic time scale, GTS）。

地质年代共分为六个时间单位，从大到小依次是宙/元（eon）、代（era）、纪（period）、世（epoch）、期（age）、时 （chron）。

按照宙级划分，整个地质年代表可以分为 4 个宙：

• 冥古宙：生命现象开始的时期
• 太古宙：初始生物的时期
• 元古宙：肉眼可见个体的多细胞生物出现
• 显生宙：现代生物存在的时期

其中前寒武纪（Precambrian）是地质年代中，对于显生宙之前数个宙的非正式涵盖统称，原本正式的名称是隐生宙或隐生元（Cryptozoic eon），但后来拆分成冥古宙、太古宙与元古宙三个宙。开始于大约 45 亿年前的地球形成时期，结束于约 5 亿 4200 万年前大量肉眼可见的硬壳动物诞生之时。

尽管前寒武纪占了地球历史中大约八分之七的时间，但人们对这段时期的了解相当少。这是因为前寒武纪少有化石纪录，且其中多数的化石，如叠层石，只适合用来作生物地层学研究。此外，许多前寒武纪时期的岩石已经严重变质，使其起源变得晦涩不明。而其它的要么已经腐蚀毁坏，要么还埋藏在显生宙地层底下。

大约在 45 亿年前左右，原始的地球从环绕太阳的物质之中聚集而成。不久之后可能又因为小行星（大小如火星）的撞击，而分离出月球（参见大碰撞说）。一开始地球表面皆为岩浆覆盖，稳固地壳则大约出现于 44 亿年前。目前已知最古老的岩石发现于澳洲西部，放射性分析显示这块锆石结晶已有大约 44 亿 400 万年历史。

对于现代生物开始存在的显生宙，化石纪录相对增多，人们的研究也较为详细。在显生宙中按照代级划分，可以分为 3 个代，代级以下共划分为 12 个纪：

• 古生代：古代生物的时期
  • 寒武纪（Cambrian）：名称来自拉丁文 Cambria ，即威尔士的古名 Cymru
  • 奥陶纪（Ordovician）：名称来自大不列颠凯尔特人的古老部落（奥陶部落）
  • 志留纪（Silurian）：名称来自大不列颠凯尔特人的古老部落（志留部落）
  • 泥盆纪（Devonian）：名称来自英国德文郡（Devonshire）
  • 石炭纪（Carboniferous）：名称来自大不列颠群岛的含煤的岩石
  • 二叠纪（Permian）：名称来自俄罗斯的彼尔姆州（Perm），二叠纪一词来自日本，因为德国的此地层分为两层
• 中生代：中等进化生物的时期
  • 三叠纪（Triassic）：名称来自拉丁文“三”（Trias），因为最初发现的地层明显分为三层
  • 侏罗纪（Jurassic）：名称来自法国与瑞士之间的汝拉山（Jura Mountain）
  • 白垩纪（Cretaceous）：名称来自拉丁文 Creta，意指白垩
• 新生代：现代生物的时期
  • 古近纪（Neogene）
  • 新近纪（Paleogene）
  • 第四纪（Quaternary）

地质年代在早期将新生代划分为第一纪、第二纪、第三纪和第四纪四个时期。第四纪是人类存在的纪；第三纪是哺乳动物出现的纪；第二纪是爬虫类动物时代，第一纪包括爬行动物出现以前时代。后来在 19 世纪时就取消了第一纪和第二纪这两个名称。而后来第三纪也被撤销，并将第三纪分为古近纪和新近纪。

地质藏点

在此地质藏点记录 log 前，请完成以下问题和任务，并发信给我（无须等待我的回复）：

1. 请在沿江路一带寻找分散摆放的海珠石，并阅读附近的简介标示牌，从中找到并回答海珠石形成于哪一个“纪”（万一标示牌被移除，可以从互联网搜索答案）。
2. 问题 1 答案的“纪”，属于哪一个“宙”和“代”？
3. 在 log 中上传一张在沿江西路一带或 GZ 附近带有“海珠石”字样的照片，照片中需要包含 Trackables/手持 GPS/Geocaching 相关软件，或任何可以表明你是寻宝者的物品。