觀音(yin)山(shan)(Kuan-yin Mountain),舊稱新(xin)宜山(shan),別(bie)名八里坌(ben)山(shan)(淡(dan)(dan)水(shui)廳志載)。位于臺(tai)灣(wan)省新(xin)北市五股(gu)區、八里區交界(jie),海拔標高616米,由淡(dan)(dan)水(shui)河北岸(an)向南遙望,全區有十八連(lian)峰(feng),區內有多座古剎,更增添觀音(yin)山(shan)的(de)靈性,其中有數間供奉觀世音(yin)菩薩的(de)觀音(yin)寺。
觀(guan)音山,亦有不少納(na)骨塔(ta)及墓園錯(cuo)落(luo)其間,該山西臨臺灣海(hai)峽(xia),東北隔淡水(shui)河遠望關渡,昔日的“坌嶺(ling)吐霧”為淡水(shui)八大景之一,山頂又(you)稱“硬漢嶺(ling)”,全山屬北海(hai)岸(an)及觀(guan)音山風景區。
觀音山(shan)(shan)自(zi)古便有登山(shan)(shan)活動,目前八里登觀音山(shan)(shan)的路線共有四(si)條主(zhu)要(yao)路線,其(qi)中以乘車(che)至觀音山(shan)(shan)風景區管理(li)處,由凌云(yun)禪寺旁鐵(tie)漢步(bu)道(dao)經硬(ying)漢嶺(ling)(ling)拾階而(er)上登頂(ding)為最(zui)熱(re)門路線。硬(ying)漢嶺(ling)(ling)為1961年憲兵(bing)學(xue)(xue)校300名學(xue)(xue)員(yuan)開辟了一條直達山(shan)(shan)頂(ding)的登山(shan)(shan)步(bu)道(dao),為鼓勵學(xue)(xue)員(yuan)學(xue)(xue)硬(ying)漢而(er)來作硬(ying)漢而(er)去,而(er)名硬(ying)漢嶺(ling)(ling)。
硬漢嶺為(wei)火山(shan)碎屑巖(yan)與凝灰角礫巖(yan)所構成,1992,1993年(nian)來時有(you)豪(hao)雨山(shan)崩(beng)土石(shi)滑動,步(bu)道毀(hui)壞并危(wei)及(ji)凌云(yun)禪寺安(an)全。寄望能有(you)效妥當的維護整修以保持靈(ling)山(shan)古剎之原有(you)古樸韻味。
由(you)于季風吹(chui)來(lai)臺灣海峽的水汽,遇到觀音(yin)山嶺的阻擋,便降下化為(wei)云霧(wu),有(you)如(ru)飄綿滾(gun)絮、變幻無(wu)常,蔚為(wei)奇(qi)觀.被文人(ren)雅士命名(ming)為(wei)“坌嶺吐(tu)霧(wu)”,名(ming)列清代(dai)淡北八(ba)景之(zhi)一。同治年間(jian)大(da)龍峒舉人(ren)陳維英曾題詩贊曰:“坌嶺微茫八(ba)里間(jian),連朝吐(tu)霧(wu)罩鴉鬟,此中定有(you)深藏(zang)貌,未許分(fen)明見一斑”。
觀(guan)音山(shan)(shan)在淡(dan)水河(he)河(he)口南畔,東與(yu)大屯山(shan)(shan)群峰隔河(he)相峙,西南毗接林口臺(tai)地(di)。形(xing)似仰(yang)臥之觀(guan)音,山(shan)(shan)頂空曠怡(yi)人(ren),立足其(qi)上可(ke)俯瞰河(he)口及淡(dan)水鎮、臺(tai)北(bei)市郊景(jing)(jing)色,為(wei)淡(dan)水八景(jing)(jing)之一(yi)。凌(ling)云古(gu)剎(cha)坐落山(shan)(shan)腰,后另建新廟于古(gu)剎(cha)后方約數百公尺處(即(ji)觀(guan)音山(shan)(shan)腹),名曰凌(ling)云禪(chan)寺,是(shi)游人(ren)休憩處。
觀音山(shan)(shan)(shan)(shan)為一錐狀(zhuang)火山(shan)(shan)(shan)(shan),是大屯火山(shan)(shan)(shan)(shan)匯最西的(de)(de)一部分,其北側以(yi)火山(shan)(shan)(shan)(shan)熔巖為主(zhu),南側以(yi)火山(shan)(shan)(shan)(shan)碎(sui)(sui)屑流為主(zhu),火成巖以(yi)安(an)山(shan)(shan)(shan)(shan)巖為主(zhu),另(ling)外含(han)有一些(xie)早期(qi)噴(pen)發的(de)(de)玄武(wu)巖,越晚期(qi)的(de)(de)噴(pen)發則形(xing)(xing)成含(han)角閃石(shi)的(de)(de)安(an)山(shan)(shan)(shan)(shan)巖。淡水河沿著觀音山(shan)(shan)(shan)(shan)麓流入(ru)臺(tai)灣海峽,因兩側的(de)(de)火山(shan)(shan)(shan)(shan)熔巖與(yu)碎(sui)(sui)屑物漫流入(ru)海,而形(xing)(xing)成火山(shan)(shan)(shan)(shan)海岸。
山(shan)(shan)(shan)上(shang)(shang)坐落著不少名剎(cha)古寺,并可(ke)溯溪(xi)(xi)觀(guan)(guan)瀑、觀(guan)(guan)鷹賞鳥、眺望半個臺北(bei)和壯麗的(de)(de)(de)大(da)(da)屯(tun)山(shan)(shan)(shan)列,是(shi)一(yi)處豐(feng)富的(de)(de)(de)自(zi)然(ran)觀(guan)(guan)賞去處。觀(guan)(guan)音山(shan)(shan)(shan)上(shang)(shang)的(de)(de)(de)山(shan)(shan)(shan)徑(jing)溪(xi)(xi)谷(gu)四通八達,登(deng)山(shan)(shan)(shan)路線林林總總、難易不同,登(deng)山(shan)(shan)(shan)客(ke)可(ke)以(yi)揀挑適合自(zi)己體力(li)的(de)(de)(de)山(shan)(shan)(shan)徑(jing)上(shang)(shang)山(shan)(shan)(shan)。其中最(zui)大(da)(da)眾(zhong)化(hua)的(de)(de)(de)路線是(shi)從五股的(de)(de)(de)觀(guan)(guan)音山(shan)(shan)(shan)站牌出(chu)發,沿山(shan)(shan)(shan)階上(shang)(shang)登(deng)凌云禪寺,再由寺后的(de)(de)(de)牌樓往上(shang)(shang)走(zou),約1小時(shi)可(ke)抵硬漢嶺。在(zai)此登(deng)高眺覽,視野遼(liao)闊,整個臺北(bei)市(shi)(shi)自(zi)新(xin)光(guang)大(da)(da)樓以(yi)北(bei)的(de)(de)(de)市(shi)(shi)景都在(zai)眼下,而對面的(de)(de)(de)大(da)(da)屯(tun)山(shan)(shan)(shan)列及淡水河(he)口山(shan)(shan)(shan)海相映的(de)(de)(de)景象更是(shi)壯觀(guan)(guan)。
白天(tian)上觀(guan)音山(shan),可隔著門墻老樹感受楞(leng)嚴閣、開山(shan)院的古(gu)樸莊嚴,遠眺淡水(shui)(shui)八景(jing)之(zhi)一(yi)的“坌(ben)領(ling)吐霧”;傍晚時(shi)(shi)分坐觀(guan)落(luo)日晚霞,淡水(shui)(shui)暮(mu)色最令人(ren)心(xin)動;或于夜幕低垂時(shi)(shi)看淡水(shui)(shui)河畔夜景(jing),萬(wan)家燈火閃爍明滅,另(ling)有一(yi)番擾攘人(ren)間之(zhi)美。
在荷蘭人(ren)(ren)統(tong)治時代(dai),觀音山叫淡水(shui)山(出現在1654年荷蘭人(ren)(ren)‘淡水(shui)與其附近村社(she)暨(ji)雞籠島略圖(tu)’中編(bian)號37的(de)Tamswijse berch),但漢人(ren)(ren)習(xi)稱八里分(坌)山,系因山邊的(de)原住民(min)部落八里坌社(she)而得名。
康熙(xi)年(nian)間(jian),乃延(yan)用八(ba)里坌(ben)山(shan)(shan)的(de)地名(康熙(xi)二(er)十四年(nian)蔣(jiang)毓英“臺灣府志(zhi)”)。清朝雍正(zheng)年(nian)間(jian)(西元1710年(nian)代(dai))也曾(ceng)改為“興直山(shan)(shan)”,但在各(ge)地方(fang)史籍中仍以“八(ba)里坌(ben)山(shan)(shan)”稱之。后來改為觀(guan)音山(shan)(shan)的(de)說法有二(er):一說是乾隆(long)17年(nian)(西元1752年(nian))客家籍貢(gong)生胡(hu)焯猷(you)(福建汀(ting)州(zhou)永定人)在山(shan)(shan)路西云巖(yan)籌建大士(shi)觀(guan)(今五股區西云巖(yan)寺)而得(de)名,一說是由(you)于山(shan)(shan)棱起伏(fu)(fu)變化,從關渡一帶(dai)眺望時,山(shan)(shan)型起伏(fu)(fu)貌(mao)似觀(guan)音菩薩(sa)的(de)面容仰天(tian)的(de)側面而得(de)名。
據臺灣(wan)著名(ming)的地(di)名(ming)學者-陳國章教(jiao)授(shou)所著的臺灣(wan)地(di)名(ming)詞典(dian),認為該地(di)的地(di)名(ming)是因“形似觀音菩薩的山”而得名(ming)。
1937年12月(yue)(yue)27日,日本(ben)殖(zhi)民當局以臺(tai)灣寶島(dao)山水(shui)風光秀麗籌劃成立(li)大屯觀音山、次高山太(tai)魯閣和新(xin)高阿里(li)山三(san)座公(gong)園(yuan),并于1941年3月(yue)(yue)10日發(fa)行紀念(nian)郵票、小全(quan)張及臺(tai)灣公(gong)園(yuan)寫真集,可惜因戰(zhan)爭而(er)延宕。
二(er)次世界大戰(zhan)結(jie)束后,臺灣回歸中國,觀音(yin)山(shan)優良的(de)屏障(zhang)、視(shi)野的(de)寬闊好(hao)山(shan)好(hao)水,為(wei)國人所認為(wei)風水寶地,濫(lan)挖濫(lan)葬,一片零(ling)亂有礙視(shi)野觀瞻。相較之下,景觀資源(yuan)大不如往昔,已失去了(le)成為(wei)公園之基本要(yao)件(jian),十分可惜(xi)。
觀音(yin)山(shan)(shan)(shan)(shan)是(shi)臺灣北(bei)部(bu)火成巖區(qu)中(zhong)(zhong)最西(xi)北(bei)側之(zhi)(zhi)火山(shan)(shan)(shan)(shan)單元(yuan),以淡(dan)水河與(yu)大(da)屯火山(shan)(shan)(shan)(shan)群遙遙相(xiang)望,基本上為單一中(zhong)(zhong)心噴(pen)發的火山(shan)(shan)(shan)(shan)碎屑、凝灰巖與(yu)熔巖交(jiao)替組成之(zhi)(zhi)復式火山(shan)(shan)(shan)(shan)。觀音(yin)山(shan)(shan)(shan)(shan)火山(shan)(shan)(shan)(shan)之(zhi)(zhi)主(zhu)體(ti)可能是(shi)一中(zhong)(zhong)央(yang)噴(pen)發之(zhi)(zhi)錐(zhui)狀(zhuang)火山(shan)(shan)(shan)(shan),錐(zhui)體(ti)半徑約1~2公里,噴(pen)發中(zhong)(zhong)心在觀音(yin)山(shan)(shan)(shan)(shan)主(zhu)峰(feng)之(zhi)(zhi)東南方。在凌云山(shan)(shan)(shan)(shan)一帶之(zhi)(zhi)半環形(xing)之(zhi)(zhi)連峰(feng)可能是(shi)火山(shan)(shan)(shan)(shan)口壁之(zhi)(zhi)西(xi)側。
在此以東,于(yu)石(shi)(shi)(shi)(shi)壁坑附(fu)近(jin)之(zhi)(zhi)地形,呈(cheng)(cheng)馬蹄狀(zhuang)之(zhi)(zhi)半圓形凹陷可(ke)能(neng)是火(huo)(huo)(huo)山(shan)(shan)(shan)口所(suo)在,但火(huo)(huo)(huo)山(shan)(shan)(shan)口之(zhi)(zhi)東壁已(yi)經爆破或(huo)(huo)熔巖(yan)溢流巖(yan)漿庫匱(kui)空塌(ta)陷而崩塌(ta),其部分碎(sui)屑(xie)構成(cheng)分布于(yu)凌云山(shan)(shan)(shan)以東地區之(zhi)(zhi)集塊巖(yan)或(huo)(huo)原(yuan)先(xian)之(zhi)(zhi)火(huo)(huo)(huo)山(shan)(shan)(shan)碎(sui)屑(xie)流與(yu)火(huo)(huo)(huo)山(shan)(shan)(shan)礫巖(yan)。觀(guan)音山(shan)(shan)(shan)火(huo)(huo)(huo)山(shan)(shan)(shan)活(huo)動時可(ke)能(neng)不(bu)猛烈,因而出(chu)露之(zhi)(zhi)主體并未含有(you)可(ke)觀(guan)的(de)火(huo)(huo)(huo)山(shan)(shan)(shan)碎(sui)屑(xie)巖(yan),仍以厚層(ceng)的(de)巖(yan)流為主。觀(guan)音山(shan)(shan)(shan)噴出(chu)熔巖(yan)流也(ye)和(he)大屯火(huo)(huo)(huo)山(shan)(shan)(shan)群相似,均以安山(shan)(shan)(shan)巖(yan)為主。一(yi)般安山(shan)(shan)(shan)巖(yan)常呈(cheng)(cheng)灰(hui)或(huo)(huo)灰(hui)黑色(se),且(qie)多呈(cheng)(cheng)斑(ban)狀(zhuang)結構,由結晶(jing)(jing)較粗大之(zhi)(zhi)斑(ban)晶(jing)(jing)散布在石(shi)(shi)(shi)(shi)質細密之(zhi)(zhi)石(shi)(shi)(shi)(shi)基(ji)中。斑(ban)晶(jing)(jing)礦(kuang)(kuang)物以鎂(mei)(mei)鐵礦(kuang)(kuang)物為多,包括橄欖石(shi)(shi)(shi)(shi)、輝石(shi)(shi)(shi)(shi)、紫蘇輝石(shi)(shi)(shi)(shi)、角閃石(shi)(shi)(shi)(shi)、黑云母等礦(kuang)(kuang)物,此外還有(you)灰(hui)白色(se)的(de)斜長石(shi)(shi)(shi)(shi)。石(shi)(shi)(shi)(shi)基(ji)以斜長石(shi)(shi)(shi)(shi)和(he)一(yi)些鎂(mei)(mei)鐵礦(kuang)(kuang)物的(de)微晶(jing)(jing)(肉眼不(bu)能(neng)分辨的(de))和(he)無(wu)結晶(jing)(jing)的(de)火(huo)(huo)(huo)山(shan)(shan)(shan)玻璃所(suo)組(zu)成(cheng)。
本區安山巖熔巖依噴發之先后,由(you)下而上可分別為三層(ceng),各層(ceng)巖石在組織上和成分上都有多少不同。
底(di)層(或(huo)第(di)(di)一層)是(shi)粗粒普通輝(hui)石(shi)玄武巖(yan)(yan)(yan)或(huo)玄武巖(yan)(yan)(yan)質安山(shan)巖(yan)(yan)(yan)熔巖(yan)(yan)(yan)。主要(yao)露(lu)出(chu)于火山(shan)錐體之(zhi)(zhi)(zhi)中(zhong)(zhong)心地帶(dai),包括石(shi)壁坑及其東側(ce)之(zhi)(zhi)(zhi)米倉(cang)村(cun)、烏山(shan)頭,至(zhi)福隆山(shan)等地。安山(shan)巖(yan)(yan)(yan)顏色深灰(hui)(hui),呈斑狀結(jie)(jie)構有許多(duo)(duo)黑(hei)綠色之(zhi)(zhi)(zhi)普通輝(hui)石(shi)斑晶(jing),散(san)布在灰(hui)(hui)色細(xi)晶(jing)之(zhi)(zhi)(zhi)石(shi)基中(zhong)(zhong),斑晶(jing)大(da)者可達5公(gong)里左右。在顯微(wei)鏡(jing)下觀察巖(yan)(yan)(yan)石(shi)薄(bo)片,這些(xie)斑晶(jing)多(duo)(duo)成(cheng)(cheng)雙晶(jing)或(huo)叢晶(jing)(由數(shu)個晶(jing)體結(jie)(jie)集而成(cheng)(cheng)),輝(hui)石(shi)之(zhi)(zhi)(zhi)外(wai)還有多(duo)(duo)數(shu)斜(xie)長石(shi)和少數(shu)橄欖石(shi)。中(zhong)(zhong)層(或(huo)第(di)(di)二層)的熔巖(yan)(yan)(yan)是(shi)由兩(liang)輝(hui)安山(shan)巖(yan)(yan)(yan)構成(cheng)(cheng)。巖(yan)(yan)(yan)石(shi)外(wai)觀灰(hui)(hui)色,普通輝(hui)石(shi)之(zhi)(zhi)(zhi)斑晶(jing)雖粗大(da)易見但甚稀(xi)少,細(xi)長之(zhi)(zhi)(zhi)紫(zi)蘇(su)輝(hui)石(shi)晶(jing)體頗多(duo)(duo)但均細(xi)小。本巖(yan)(yan)(yan)石(shi)之(zhi)(zhi)(zhi)石(shi)基占量較多(duo)(duo),由斜(xie)長石(shi)和紫(zi)蘇(su)輝(hui)石(shi)細(xi)晶(jing)以及火山(shan)玻璃所組(zu)成(cheng)(cheng)。本層是(shi)觀音山(shan)中(zhong)(zhong)露(lu)出(chu)面積最廣的熔巖(yan)(yan)(yan),主要(yao)分布于觀音山(shan)主峰北側(ce)之(zhi)(zhi)(zhi)山(shan)坡。
第(di)二(er)層(ceng)(ceng)斑晶(jing)(jing)稀疏之(zhi)兩(liang)輝(hui)(hui)(hui)(hui)安(an)山(shan)(shan)(shan)(shan)巖(yan)(yan)(yan)(yan)(yan)(yan)(yan),常含(han)第(di)一層(ceng)(ceng)輝(hui)(hui)(hui)(hui)石(shi)(shi)(shi)(shi)(shi)(shi)斑晶(jing)(jing)多(duo)而聚集(ji)成叢的(de)(de)(de)(de)普通(tong)輝(hui)(hui)(hui)(hui)石(shi)(shi)(shi)(shi)(shi)(shi)安(an)山(shan)(shan)(shan)(shan)巖(yan)(yan)(yan)(yan)(yan)(yan)(yan)之(zhi)捕獲巖(yan)(yan)(yan)(yan)(yan)(yan)(yan)塊,根據(ju)(ju)年代對比(bi)的(de)(de)(de)(de)包裹定律,即可(ke)知其發生(sheng)之(zhi)先后順(shun)序,乃(nai)輝(hui)(hui)(hui)(hui)石(shi)(shi)(shi)(shi)(shi)(shi)安(an)山(shan)(shan)(shan)(shan)巖(yan)(yan)(yan)(yan)(yan)(yan)(yan)(第(di)一層(ceng)(ceng))早于(yu)兩(liang)輝(hui)(hui)(hui)(hui)安(an)山(shan)(shan)(shan)(shan)巖(yan)(yan)(yan)(yan)(yan)(yan)(yan)(第(di)二(er)層(ceng)(ceng))。頂(ding)層(ceng)(ceng)(第(di)三層(ceng)(ceng))紫蘇(su)(su)輝(hui)(hui)(hui)(hui)石(shi)(shi)(shi)(shi)(shi)(shi)安(an)山(shan)(shan)(shan)(shan)巖(yan)(yan)(yan)(yan)(yan)(yan)(yan)與(yu)一部(bu)分(fen)角閃(shan)石(shi)(shi)(shi)(shi)(shi)(shi)紫蘇(su)(su)安(an)山(shan)(shan)(shan)(shan)巖(yan)(yan)(yan)(yan)(yan)(yan)(yan)為(wei)(wei)其特征(zheng),顏色淡灰(hui)(hui)色或(huo)(huo)灰(hui)(hui)紫,斑晶(jing)(jing)細(xi)小(xiao)不(bu)顯(xian)著。有(you)(you)時可(ke)見有(you)(you)細(xi)長之(zhi)紫蘇(su)(su)輝(hui)(hui)(hui)(hui)石(shi)(shi)(shi)(shi)(shi)(shi)或(huo)(huo)角閃(shan)石(shi)(shi)(shi)(shi)(shi)(shi)之(zhi)小(xiao)晶(jing)(jing),石(shi)(shi)(shi)(shi)(shi)(shi)基(ji)較(jiao)多(duo)包含(han)微晶(jing)(jing)與(yu)玻璃質(zhi)(zhi)。本層(ceng)(ceng)主要分(fen)布在(zai)(zai)火山(shan)(shan)(shan)(shan)中央之(zhi)頂(ding)部(bu),由(you)(you)觀(guan)音(yin)山(shan)(shan)(shan)(shan)主峰至崩(beng)山(shan)(shan)(shan)(shan)一帶。在(zai)(zai)本地(di)區(qu)內除上述之(zhi)三層(ceng)(ceng)熔巖(yan)(yan)(yan)(yan)(yan)(yan)(yan)流之(zhi)外,還有(you)(you)兩(liang)處(chu)獨(du)立之(zhi)小(xiao)規模(mo)火山(shan)(shan)(shan)(shan)巖(yan)(yan)(yan)(yan)(yan)(yan)(yan)體,一是(shi)(shi)在(zai)(zai)觀(guan)音(yin)山(shan)(shan)(shan)(shan)站北側公路旁出露之(zhi)黑云母角閃(shan)安(an)山(shan)(shan)(shan)(shan)巖(yan)(yan)(yan)(yan)(yan)(yan)(yan)脈,為(wei)(wei)一厚約20~40公尺之(zhi)脈狀(zhuang)小(xiao)侵入體(或(huo)(huo)稱(cheng)觀(guan)音(yin)坑巖(yan)(yan)(yan)(yan)(yan)(yan)(yan)脈),穿入觀(guan)音(yin)山(shan)(shan)(shan)(shan)層(ceng)(ceng)之(zhi)粉砂巖(yan)(yan)(yan)(yan)(yan)(yan)(yan)之(zhi)中。另一處(chu)是(shi)(shi)突出于(yu)成子寮附近低(di)地(di)上之(zhi)萬(wan)年塔小(xiao)山(shan)(shan)(shan)(shan),巖(yan)(yan)(yan)(yan)(yan)(yan)(yan)石(shi)(shi)(shi)(shi)(shi)(shi)是(shi)(shi)橄欖(lan)(lan)石(shi)(shi)(shi)(shi)(shi)(shi)玄(xuan)(xuan)武巖(yan)(yan)(yan)(yan)(yan)(yan)(yan),可(ke)能是(shi)(shi)一火山(shan)(shan)(shan)(shan)側噴發之(zhi)巖(yan)(yan)(yan)(yan)(yan)(yan)(yan)體。萬(wan)年塔所產出者,其橄欖(lan)(lan)石(shi)(shi)(shi)(shi)(shi)(shi)含(han)量(liang)較(jiao)普通(tong)輝(hui)(hui)(hui)(hui)石(shi)(shi)(shi)(shi)(shi)(shi)為(wei)(wei)多(duo),與(yu)福隆山(shan)(shan)(shan)(shan)玄(xuan)(xuan)武巖(yan)(yan)(yan)(yan)(yan)(yan)(yan)略有(you)(you)不(bu)同。根據(ju)(ju)結晶(jing)(jing)分(fen)化的(de)(de)(de)(de)效應,玄(xuan)(xuan)武質(zhi)(zhi)巖(yan)(yan)(yan)(yan)(yan)(yan)(yan)漿(jiang)經(jing)由(you)(you)橄欖(lan)(lan)石(shi)(shi)(shi)(shi)(shi)(shi)、輝(hui)(hui)(hui)(hui)石(shi)(shi)(shi)(shi)(shi)(shi)與(yu)斜長石(shi)(shi)(shi)(shi)(shi)(shi)的(de)(de)(de)(de)結晶(jing)(jing)分(fen)化可(ke)以產生(sheng)安(an)山(shan)(shan)(shan)(shan)巖(yan)(yan)(yan)(yan)(yan)(yan)(yan)。同樣的(de)(de)(de)(de)由(you)(you)混(hun)染作(zuo)用,也就是(shi)(shi)由(you)(you)基(ji)性的(de)(de)(de)(de)巖(yan)(yan)(yan)(yan)(yan)(yan)(yan)漿(jiang)與(yu)酸性的(de)(de)(de)(de)巖(yan)(yan)(yan)(yan)(yan)(yan)(yan)漿(jiang)混(hun)合(he),或(huo)(huo)是(shi)(shi)由(you)(you)玄(xuan)(xuan)武質(zhi)(zhi)巖(yan)(yan)(yan)(yan)(yan)(yan)(yan)漿(jiang),混(hun)雜了(le)沈(shen)積(ji)物或(huo)(huo)地(di)殼物質(zhi)(zhi)都可(ke)能衍生(sheng)成安(an)山(shan)(shan)(shan)(shan)巖(yan)(yan)(yan)(yan)(yan)(yan)(yan)。在(zai)(zai)觀(guan)音(yin)山(shan)(shan)(shan)(shan)地(di)區(qu)安(an)山(shan)(shan)(shan)(shan)巖(yan)(yan)(yan)(yan)(yan)(yan)(yan)或(huo)(huo)玄(xuan)(xuan)武巖(yan)(yan)(yan)(yan)(yan)(yan)(yan)中,常含(han)有(you)(you)火山(shan)(shan)(shan)(shan)體基(ji)底的(de)(de)(de)(de)砂巖(yan)(yan)(yan)(yan)(yan)(yan)(yan)或(huo)(huo)硅質(zhi)(zhi)片巖(yan)(yan)(yan)(yan)(yan)(yan)(yan),顯(xian)示地(di)殼物質(zhi)(zhi)的(de)(de)(de)(de)混(hun)染作(zuo)用具有(you)(you)舉足輕重(zhong)的(de)(de)(de)(de)角色。
觀(guan)音山(shan)各火(huo)(huo)山(shan)體(ti)的(de)噴(pen)發時代,根據鉀(jia)-氬法定年(nian)的(de)結果來看(kan),觀(guan)音山(shan)火(huo)(huo)山(shan)之活動(dong)盛行于(yu)第(di)四(si)紀。由六(liu)十(shi)余(yu)萬年(nian)前開始(shi);接(jie)著(zhu)是五十(shi)余(yu)萬年(nian)前底層輝石玄(xuan)(xuan)武(wu)巖(yan)(yan)或(huo)玄(xuan)(xuan)武(wu)巖(yan)(yan)質(zhi)熔巖(yan)(yan)之噴(pen)發;其次(ci)(ci)則為(wei)四(si)十(shi)余(yu)萬年(nian)前,第(di)二層兩輝安(an)山(shan)巖(yan)(yan);再依次(ci)(ci)為(wei)三十(shi)余(yu)萬年(nian)前第(di)三層紫蘇輝石與紫蘇輝石角閃安(an)山(shan)巖(yan)(yan)之噴(pen)發;最后(hou)以二十(shi)余(yu)萬年(nian)前橄(gan)欖玄(xuan)(xuan)武(wu)巖(yan)(yan)落幕。由火(huo)(huo)山(shan)噴(pen)發年(nian)代與塌(ta)陷(xian)破火(huo)(huo)山(shan)口地貌(mao)看(kan)來,觀(guan)音山(shan)非為(wei)活火(huo)(huo)山(shan),有可能(neng)是座(zuo)休眠(mian)火(huo)(huo)山(shan)或(huo)死火(huo)(huo)山(shan)。
1937年(nian)12月27日(ri)成(cheng)(cheng)立(li)大屯公園,觀(guan)音山(shan)(shan)(shan)亦在其中。但戰后(hou)(hou)成(cheng)(cheng)立(li)的陽明(ming)山(shan)(shan)(shan)公園剔除觀(guan)音山(shan)(shan)(shan)(2002年(nian)方(fang)另成(cheng)(cheng)立(li)北海岸及(ji)觀(guan)音山(shan)(shan)(shan)風景區管理),以及(ji)民間認為此山(shan)(shan)(shan)為風水寶地,埋下日(ri)后(hou)(hou)濫(lan)(lan)墾濫(lan)(lan)葬及(ji)水土(tu)保(bao)持的問題。據估計目前山(shan)(shan)(shan)上非法墓計4萬處,成(cheng)(cheng)為發展阻礙。